Page 1 ECH630-ECH749, CH735, CH26, CH745 Service Manual IMPORTANT: Read all safety precautions and instructions carefully before operating equipment. Refer to operating instruction of equipment that this engine powers. Ensure engine is stopped and level before performing any maintenance or service. Safety Maintenance Speciﬁ...
Page 2 Safety SAFETY PRECAUTIONS WARNING: A hazard that could result in death, serious injury, or substantial property damage. CAUTION: A hazard that could result in minor personal injury or property damage. NOTE: is used to notify people of important installation, operation, or maintenance information. CAUTION WARNING WARNING...
Page 3 PRO oil and PRO filter. ® REPAIRS/SERVICE PARTS Kohler genuine service parts can be purchased from Kohler authorized dealers. To ﬁ nd a local Kohler authorized dealer visit KohlerEngines.com or call 1-800-544-2444 (U.S. and Canada). 24 690 01 Rev. S...
Page 4 KOHLER PRO Extended Life Oil Filter. Alternative full-synthetic oil). Remove spark plug(s) and pour engine oils and oil ﬁ lters may be used with KOHLER about 1 oz. of engine oil into cylinder(s). Replace engines but require 100-Hour oil and 200-Hour oil ﬁ lter spark plug(s) and crank engine slowly to distribute change intervals for proper maintenance.
Page 5 Speciﬁ cations Engine Dimensions with Heavy-Duty Air Cleaner-Flywheel Side 342.52 mm Valve Cover 451.16 mm (17.762 in.) Fuel Pump (13.485 in.) 88.28 mm 298.93 mm 230.20 mm (9.063 in.) 130.0 mm (5.118 in.) (3.475 in.) (11.769 in.) 77.17 mm 67.19 mm 277.22 mm (10.914 in.) 135.0 mm (5.315 in.) (3.038 in.) Spark Plug...
Page 6 Speciﬁ cations Engine Dimensions with Heavy-Duty Air Cleaner-Oil Filter Side 30.0 mm (1.181 in.) 371.44 mm 209.88 mm (8.263 in.) 52.43 mm (2.064 in.) Spark Plug Center (14.624 in.) Line 32.00 mm (1.260 in.) Oil Fill Dipstick 101.38 mm (3.992 in.) Exhaust Port #2 7/16-20 UNF-2B in.
Page 7 Speciﬁ cations Engine Dimensions with Heavy-Duty Air Cleaner-PTO Side 65.0 mm (2.559 in.) 335.04 mm (13.19 in.) 122.10 mm (4.807 in.) 75.42 mm (2.969 in.) Muﬄ er Mounting 50.00 mm (1.969 in.) Lift Strap Oil Fill Location 30° Exhaust Port #2 5/16-24 UNC-2B in.
Page 8 Speciﬁ cations Engine Dimensions with Heavy-Duty Air Cleaner-Starter Side 50.0 mm (1.969 in.) 67.50 mm (2.657 in.) 12.0 mm (0.472 in.) Center Line Spark Muﬄ er Mounting Dipstick Exhaust Port #1 Plug Bosses 432.58 mm Engine Mounting Center Line Mounting 89.0 mm (3.504 in.) (17.031 in.) Surface...
Page 9 Speciﬁ cations Engine Dimensions with Low-Proﬁ le Air Cleaner-Flywheel Side 451.16 mm (17.762 in.) 298.93 mm (11.769 in.) Valve Cover 12.95 mm (0.510 in.) 67.19 mm 77.17 mm 37.15 mm 473.43 mm (2.645 in.) Spark (3.038 in.) Spark (1.463 in.) Spark (18.639 in.) Plug Boot Removal Plug Removal...
Page 10 Speciﬁ cations Engine Dimensions with Low-Proﬁ le Air Cleaner-Oil Filter Side 30.0 mm (1.181 in.) 371.44 mm Spark Plug Center Fuel Pump Oil Fill (14.624 in.) Line 85.50 mm (3.366 in.) Dipstick 101.38 mm (3.992 in.) 1/4 in. Square Keyway Keyway 7/16-20 UNF 2B in.
Page 11 Speciﬁ cations Engine Dimensions with Low-Proﬁ le Air Cleaner-PTO Side 65.0 mm (2.559 in.) 335.04 mm (13.19 in.) 122.10 mm (4.807 in.) 75.42 mm (2.969 in.) Muﬄ er Mounting 50.00 mm (1.969 in.) Lift Strap Oil Fill Location 30° Exhaust Port #2 5/16-24 UNC-2B in.
Page 12 Speciﬁ cations Engine Dimensions with Low-Proﬁ le Air Cleaner-Starter Side 50.0 mm (1.969 in.) 12.0 mm (0.472 in.) 32.0 mm (1.260 in.) Center Line Spark Dipstick Exhaust Port #1 Exhaust Port #2 Plug 67.50 mm (2.657 in.) 432.58 mm Engine Mounting Center Line Mounting Muﬄ...
Page 13 Lubricate threads with engine oil prior to assembly. Any and all horsepower (hp) references by Kohler are Certiﬁ ed Power Ratings and per SAE J1940 & J1995 hp standards. Details on Certiﬁ ed Power Ratings can be found at KohlerEngines.com.
Page 14 Speciﬁ cations TORQUE SPECIFICATIONS ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 Crankcase Breather Cover Fastener 11.3 N·m (100 in. lb.) into new holes 7.3 N·m (65 in. lb.) into used holes Engine Temperature Sensor (into 7.3 N·m (65 in. lb.) breather cover) Oil Sentry (into breather cover) 4.5 N·m (40 in.
Page 15 Speciﬁ cations TORQUE SPECIFICATIONS ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 Ignition (continued) Rectiﬁ er-Regulator Fastener (Standard 1.4 N·m (12.6 in. lb.) Charging System) Rectiﬁ er-Regulator Power Studs/Nuts 4.0 N·m (35 in. lb.) (High Output Charging System) Rectiﬁ er-Regulator Terminal Block 2.8 N·m (25 in. lb.) Cover Fastener (High Output Charging System) Rectiﬁ...
Page 16 Speciﬁ cations TORQUE SPECIFICATIONS ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 Muﬄ er Retaining Nut 27.8 N·m (246 in. lb.) 24.4 N·m (216 in. lb.) Oxygen Sensor smaller 14 mm 18 N·m (159 in. lb.) (9/16 in.) wrench size Oxygen Sensor larger 22 mm (7/8 in.) 50.1 N·m (37 ft .
Page 17 Speciﬁ cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Camshaft End Play (with shim) 0.101/0.406 mm (0.0040/0.0160 in.) 0.076/0.127 mm (0.0030/0.0050 in.) Running Clearance 0.025/0.105 mm (0.001/0.004 in.) 0.025/0.063 mm (0.0010/0.0025 in.) Bore I.D. 20.000/20.025 mm (0.7874/0.7884 in.) 20.000/20.025 mm (0.7874/0.7884 in.) Max.
Page 18 Speciﬁ cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Crankshaft (continued) Crankshaft Bore (In Closure Plate)-to-Crankshaft Running Clearance 0.039/0.074 mm (0.0015/0.0029 in.) 0.039/0.087 mm (0.0015/0.0034 in.) Flywheel End Main Bearing Journal O.D. - New 40.913/40.935 mm (1.6107/1.6116 in.) 40.913/40.935 mm (1.6107/1.6116 in.) O.D.
Page 19 Speciﬁ cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Governor (if equipped) Governor Cross Shaft -to- Crankcase Running Clearance 0.025/0.126 mm (0.0009/0.0049 in.) 6 mm Shaft 0.013/0.075 mm (0.0005/0.0030 in.) 8 mm Shaft 0.025/0.126 mm (0.0009/0.0049 in.) Cross Shaft O.D. 7.949/8.000 mm (0.3129/0.3149 in.) Max.
Page 20 Speciﬁ cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Piston Style A (continued) Thrust Face O.D. 79.943/79.961 mm 82.949/82.967 mm (3.2657/3.2664 in.) (3.1473/3.1480 in.) Max. Wear Limit 79.816 mm 82.822 mm (3.2606 in.) (3.1423 in.) Piston Thrust Face-to Cylinder Bore Running Clearance 0.039/0.082 mm (0.0015/0.0032 in.) Piston Style B...
Page 21 Speciﬁ cations CLEARANCE ECH630-ECH680 ECH730-ECH749 CH26 CH735 CH745 SPECIFICATIONS Valves and Valve Lifters Hydraulic Lifter to Crankcase 0.011/0.048 mm (0.0004/0.0019 in.) 0.0241/0.0501 mm (0.0009/0.0020 in.) Running Clearance Intake Valve Stem-to-Valve 0.040/0.078 mm (0.0016/0.0031 in.) 0.038/0.076 mm (0.0015/0.0030 in.) Guide Running Clearance Exhaust Valve Stem-to-Valve 0.052/0.090 mm (0.0020/0.0035 in.) 0.050/0.088 mm (0.0020/0.0035 in.)
Page 22 Speciﬁ cations GENERAL TORQUE VALUES English Fastener Torque Recommendations for Standard Applications Bolts, Screws, Nuts and Fasteners Assembled Into Cast Iron or Steel Grade 2 or 5 Fasteners Into Aluminum Size Grade 2 Grade 5 Grade 8 Tightening Torque: N·m (in. lb.) ± 20% 8-32 2.3 (20) 2.8 (25)
Page 23 Shrader Valve Adapter Hose DTI-037 Wire Probe Set (2 pieces regular wire with clip; 1 piece fused wire) DTI-031 Hose Removal Tool, Dual Size/End (also sold as individual Kohler tool) DTI-033 K-Line Adapter Jumper Lead Wiring Harness Kohler 25 176 23-S...
Page 24 Source/Part No. Mobile KDS Gen 2 (Wireless) Module (New CAN bus/ETB capable) Kohler 25 761 55-S Replaces the previous Kohler 25 761 45-S for mobile Android or iOS EFI diagnostics. Components of 25 761 55-S 7 Pin to DB9 Cable...
Page 25 Source/Part No. Camshaft Lubricant (Valspar ZZ613) Kohler 25 357 14-S Dielectric Grease Loctite 51360 ® Kohler Electric Starter Drive Lubricant (Inertia Drive) Kohler 52 357 01-S P80 Emulsion Lubricant Kohler 25 357 80-S RTV Silicone Sealant Loctite 5900 Heavy Body in 4 oz. aerosol dispenser.
Page 26 Troubleshooting TROUBLESHOOTING GUIDE When troubles occur, be sure to check simple causes which, at ﬁ rst, may seem too obvious to be considered. For example, a starting problem could be caused by an empty fuel tank. Some general common causes of EFI engine troubles are listed below and vary by engine speciﬁ cation. Use these to locate causing factors.
Page 27 Troubleshooting Sludge is a natural by-product of combustion; a small Engine Loses Power accumulation is normal. Excessive sludge formation ● Dirty air cleaner element. could indicate over rich fuel settings, weak ignition, ● Engine overheated. overextended oil change interval or wrong weight or ●...
Page 28 Troubleshooting CRANKCASE VACUUM TEST WARNING WARNING Carbon Monoxide can cause severe nausea, Rotating Parts can cause severe injury. fainting or death. Stay away while engine is in operation. Avoid inhaling exhaust fumes. Never run engine indoors or in enclosed spaces. Keep hands, feet, hair, and clothing away from all Engine exhaust gases contain poisonous carbon moving parts to prevent injury.
Page 29 Troubleshooting COMPRESSION TEST NOTE: On engines with electronic throttle body (ETB), use Compression test within KOHLER Diagnostic System ® (KDS) Gen 2. See instructions within help (?) area of compression test. A compression test is best performed on a warm engine. Clean any dirt or debris away from base of spark plugs before removing them.
Page 30 Troubleshooting Test Pressure Chart for Dual Gauge Tool Left Gauge Regulated Pressure Selection Right Gauge Reading in PSI 80 PSI Recommended for engines over 200 cc or those exhibiting high leakage at 35 PSI setting. 35 PSI Recommended for single cylinder 31.5 24.5 17.5...
Page 31 Air Cleaner/Intake AIR CLEANER Low-Proﬁ le These systems are CARB/EPA certiﬁ ed and components Loosen knob(s) and remove air cleaner cover. should not be altered or modiﬁ ed in any way. Precleaner Low-Proﬁ le Air Cleaner 1. Remove precleaner from paper element. 2.
Page 32 ● Oxygen sensor has warmed suﬃ ciently to provide a signal (minimum 400°C, 752°F). FUEL LINE ● Engine operation is at a steady state (not starting, Low permeation fuel line must be installed on all Kohler warming up, accelerating, etc.). Co. engines to maintain EPA and CARB regulatory compliance.
Page 33 A technician can started. Sensor must be properly connected at all times. access stored fault code using a blink code diagnosis If sensor becomes disconnected for any reason, engine ﬂ ashed out through MIL or use KOHLER Diagnostic will quit running. ®...
Page 34 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Purpose of sensing air temperature is to help ECU A high-voltage, solid-state, battery ignition system is calculate air density. Higher air temperature less dense used with EFI system. ECU controls ignition output and air becomes. As air becomes less dense ECU knows timing through transistorized control of primary current that it needs to lessen fuel ﬂ...
Page 35 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH High pressure fuel line is an assembly of hoses, injector IMPORTANT NOTES! caps and a fuel connector to fuel pump module. High ● Cleanliness is essential and must be maintained at all pressure fuel line feeds fuel to top of injectors through times when servicing or working on EFI system.
Page 36 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH ELECTRICAL COMPONENTS Grey Connector Side Electronic Control Unit (ECU) Pin # Description Pinout of ECU Not Used Black Connector Side Not Used Pin # Description Malfunction Indicator Light (MIL) Ground Ignition Coil #1 Ground Not Used Battery Ground Not Used...
Page 37 1. Turn key/ignition OFF. void if case is opened or tampered with in any way. 2. Install Green colored wire jumper from Kohler EFI All operating and control functions within ECU are service kit on to diagnostic port (or connect white preset.
Page 38 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH KohlerEngines.com 24 690 01 Rev. S...
Page 39 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH ETB EFI Wiring Harness 20 Amp Detail Stator Rectiﬁ er-Regulator Purple 30A Fuse Battery Black Red/Black Pink Fuel Pump Module Red/White White 8-Terminal Connector Red/Yellow Green/White Dark Blue Starter Motor Dark Green Oil Pressure Switch Yellow/Black 10A Fuse Grey Connector...
Page 40 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH KohlerEngines.com 24 690 01 Rev. S...
Page 41 (approx. 3900 RPM). If speed DOES increase, problem is with OEM control system. Consult OEM service information for OEM diagnostics. If speed DOES NOT increase, problem is with engine ETB system. This can be tested using KOHLER Diagnostic ®...
Page 42 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH KohlerEngines.com 24 690 01 Rev. S...
Page 43 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH ETB EFI Wiring Harness High Output Charging System Detail Rectiﬁ er-Regulator Purple Kohler 60A Fuse* Black Stator Battery Red/Black Pink Fuel Pump Module Red/White White 8-Terminal Connector Red/Yellow Green/White Dark Blue Starter Motor Dark Green...
Page 44 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH If only a volt meter is available 5. Unplug sensor from wire harness and check sensor resistance separately across two pins. Resistance Measure voltage supply to sensor from ECU. This value should again be 9800-10200 Ω. voltage should be 5.00 +/- 0.20 volts.
Page 45 Pin D Sensor Ground sensor problems in ﬁ eld. 14 mm or 9/16 in. 12 mm x 1.25 Using KOHLER Diagnostic System (KDS) Gen 2, see Wrench Size Thread Size ® Tools and Aids, connected to ECU is a useful technique Installation Torque 18 N·m (159 in.
Page 46 1. Look for a damaged or disconnected sensor-to- 1. With sensor connected and using KOHLER ® engine harness connection. Diagnostic System (KDS) Gen 2, see Tools and Aids, start engine to observe O2 sensor activity. Run 2.
Page 47 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Sensor Removal Inspection NOTE: Apply anti-seize compound only to threads. Anti-seize compound will aﬀ ect sensor performance if it gets into lower shield of sensor. 1. If sensor has heavy deposits on lower shield, engine, oil, or fuel may be source. 2.
Page 48 Perform repairs as necessary. Cold engine. Engine temperature Normal operation, or engine operated below 150°F (66°C) as displayed by in an excessively cold environment. KOHLER Diagnostic System (KDS) ® Gen 2, see Tools and Aids. Rich biased sensor failure. Replace sensor.
Page 49 10.5 N·m (93 in. lb.). An ECU Reset will need to be on one cylinder) or a change in injector noise or completed. vibration. 3. Using KOHLER Diagnostic System (KDS) Gen 2, ® see Tools and Aids, perform Adjust Injector Timing 24 690 01 Rev.
Page 50 Using an ohmmeter set on Rx1 scale, check resistance high pressure fuel line. Insert pressure test jumper in circuits as follows: (from Kohler EFI Service Kit) between high pressure fuel line and FPM. 1. To check cylinder coil 1 (starter side), disconnect Black connector from ECU and test between Black 2.
Page 51 Please note vent hose routing and replicate after service or component replacement to prevent pinching or abrasion of vent hoses. Only Kohler replacement parts can be used because ﬁ tting is speciﬁ c to system and must be maintained. Visit KohlerEngines.com for recommended Kohler replacement parts.
Page 52 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Troubleshooting Guide Condition Possible Cause Faulty spark plugs. Fuel pump not running. Fuel pressure low. Insuﬃ cient fuel delivery. Engine Starts Hard TPS set incorrect (ECU Reset). or Fails to Start Crankshaft position sensor loose or faulty. When Hot.
Page 53 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Function Test Fault Codes Example of Diagnostic Display WARNING High Pressure Fluids can puncture skin and cause severe injury or death. One second pause Do not work on fuel system without proper Fault training or safety equipment. Code One second pause Fluid puncture injuries are highly toxic and hazardous.
Page 54 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code Summary SAE J1939 Fault Codes Fault Code MIL Blinks Connection or Failure Description P2119 1/5/2/11 Throttle Actuator Stuck 5419 P2100 1/5/2/11 Throttle Actuator Control Motor Circuit Open (Low Current Fault) 5419 P0171 1/10/8/13 Maximum Adaptation Limit Exceeded 4237...
Page 55 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH MIL may not be provided with engine. If equipment manufacturer has not added a MIL to equipment, one can be added easily for quick diagnostics. Main engine to vehicle connection will have a tan wire which is ground for MIL. Either incandescent or LED type bulbs can be used for MIL as long as they do not draw more than 0.1 amps.
Page 56 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code MIL Blinks Fault Code MIL Blinks Code P0112 10/10/6/9 Code P0117 10/10/6/14 Component: Intake Air Temperature (TMAP) Component: Engine Temperature Sensor Fault: Intake Air Temperature Sensor Circuit Fault: Engine Temperature Sensor Circuit Low Low Voltage Voltage Condition:...
Page 57 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code MIL Blinks Fault Code MIL Blinks Code P0122 10/10/3/3 Code P0131 10/11/15/10 3056 Component: Throttle Position Sensor (TPS) Component: Oxygen Sensor Fault: TPS Circuit Low Voltage or Open Fault: O2S 1 Circuit Low Voltage Condition: Open connection, broken wire or faulty Condition:...
Page 58 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code MIL Blinks Fault Code MIL Blinks Code P0171 1/10/8/13 4237 Code P0172 1/10/8/13 4237 Component: Fuel System Component: Fuel System Fault: Maximum adaptation limit exceeded Fault: Minimum adaptation limit exceeded Condition: Fuel inlet screen/ﬁ lter plugged, low Condition: Too high pressure at high pressure fuel pressure at high pressure fuel line, TPS...
Page 59 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code MIL Blinks Fault Code MIL Blinks Code P0174 1/10/8/13 4237 Code P0202 10/2/8/11 Component: Fuel Injector Component: Fuel System Fault: Injector 2 Circuit Malfunction Fault: Lean fuel condition Condition: Injector damaged or faulty, shorted or Condition: Fuel inlet screen/ﬁ...
Page 60 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code MIL Blinks Fault Code MIL Blinks Code P0230 10/5/4/3 1347 Code P0337 10/2/7/12 NOTE: If fault code P0337 is present and engine does Component: Fuel Pump not start/run, proceed to step 1 of Crankshaft Fault: Circuit Low Voltage or Open Position Sensor earlier in this section.
Page 61 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Fault Code MIL Blinks Fault Code MIL Blinks Code P0351 10/4/15/4 1268 Code P0563 10/10/6/8 Component: Ignition Coil Component: System Voltage Fault: Cylinder 1 Ignition Coil Malfunction Fault: System Voltage High Condition: Broken/shorted wire in harness (may not Condition: Faulty voltage regulator or shorted be visible), shorted connection or faulty...
Page 62 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH EFI Diagnostic Flow Diagram START OF TEST PROCEED TO START OF TEST FOR RETEST KEY ON ETB AND FUEL PUMP CYCLE? REFER TO DIAGNOSTIC AID #1 MALFUNCTION INDICATOR SYSTEM POWER LIGHT ON? REFER TO ARE FAULT CODES FAULT (P) CODE SUMMARY PRESENT?
Page 63 ● Plug wire supply to bulb will be part of vehicle wire ● Coil harness. Kohler key switch model will have MIL ● Coil circuit(s), pin circuits Grey 10 and Black 1. on engine with 12V supply to bulb. ● ECU grounds Conclusion ●...
Page 64 EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB) ECH Diagnostic Aid #11 SPEED CONTROL-CAN Communications (engine speed does not change when requested) Condition ● Speed request from OEM CAN controller is not being received by engine. Consult OEM service information for OEM diagnostics. ●...
Page 65 These adaptive values are maintained as long as ECU is not reset. Low permeation fuel line must be installed on all Kohler Co. engines to maintain EPA and CARB regulatory During certain operating periods such as cold starts, compliance.
Page 66 EFI SYSTEM-ECH WITH OXYGEN SENSOR ECU compares input signals to programmed maps in Crankshaft Position Sensor Bracket its memory to determine appropriate fuel and spark requirements for immediate operating conditions. ECU then sends output signals to set injector duration and ignition timing.
Page 67 EFI SYSTEM-ECH WITH OXYGEN SENSOR Earlier engines have a separate intake air temperature Fuel injectors mount into intake manifold, and high (IAT) sensor (located in throttle body) and a manifold pressure fuel line attaches to them at top end. absolute pressure (MAP) sensor. Later engines have Replaceable O-rings on both ends of injector prevent a combined temperature/manifold absolute pressure external fuel leakage and also insulate it from heat and...
Page 68 EFI SYSTEM-ECH WITH OXYGEN SENSOR Fuel pump module is rated for a minimum output of 13.5 For starting and warm up, ECU will adjust fuel and liters per hour and regulated at 270 kilopascals (39 psi). ignition timing, based upon ambient temperature, engine temperature, and loads present.
Page 69 EFI SYSTEM-ECH WITH OXYGEN SENSOR ELECTRICAL COMPONENTS Grey Connector Side Electronic Control Unit (ECU) Pin # Description Pinout of ECU Not Used Black Connector Side Not Used Pin # Function Malfunction Indicator Light (MIL) Ground Ignition Coil #1 Ground Not Used Battery Ground Not Used Diagnostic Communication Line...
Page 70 ECU Reset Procedure 1. Turn key/ignition OFF. 2. Install Red wire jumper from Kohler EFI service kit on to service port (connect white wire to black wire in 4 way diagnostic port). 3. Turn key/ignition ON, then OFF and count 10 seconds.
Page 71 EFI SYSTEM-ECH WITH OXYGEN SENSOR 24 690 01 Rev. S KohlerEngines.com...
Page 72 EFI SYSTEM-ECH WITH OXYGEN SENSOR KohlerEngines.com 24 690 01 Rev. S...
Page 73 EFI SYSTEM-ECH WITH OXYGEN SENSOR 24 690 01 Rev. S KohlerEngines.com...
Page 74 EFI SYSTEM-ECH WITH OXYGEN SENSOR KohlerEngines.com 24 690 01 Rev. S...
Page 75 EFI SYSTEM-ECH WITH OXYGEN SENSOR Contacting (Brush) Type TPS Crankshaft Position Sensor Resistance Table Throttle Between Resistance Continuity Position Terminal Value (Ω) Closed A & C 1400-1800 Full with A & C 3200-4100 Stop Pin Full without A & C 4600-5200 Stop Pin A &...
Page 76 EFI SYSTEM-ECH WITH OXYGEN SENSOR 7. Remove two mounting screws from TPS. Save Replace Magnet Assembly screws for reuse. Remove and discard faulty TPS. Install replacement TPS and secure with original mounting screws. a. Reconnect Black and TPS connector plugs. b.
Page 77 EFI SYSTEM-ECH WITH OXYGEN SENSOR Engine Temperature Sensor Manifold Absolute Pressure Sensor (MAP) A sealed, non-serviceable assembly. A faulty sensor A sealed, non-serviceable assembly. A faulty sensor must be replaced. If a blink code indicates a problem must be replaced. If a blink code indicates a problem with temperature sensor, it can be tested as follows: with manifold absolute pressure sensor, it can be tested as follows:...
Page 78 EFI SYSTEM-ECH WITH OXYGEN SENSOR 6. Check circuits (input, ground), from main harness Cutaway Oxygen Sensor Components (O connector to sensor plug for continuity, damage, etc. Connect one ohmmeter lead to Black pin 8 in main harness connector (as in step 4). Connect other lead to terminal #3 in sensor plug.
Page 79 EFI SYSTEM-ECH WITH OXYGEN SENSOR Sensor Signal Observation Removal Inspection NOTE: Do not cut into or pierce sensor or engine NOTE: Apply anti-seize compound only to threads. wiring to make this connection. Sensor Anti-seize compound will aﬀ ect sensor produces a very small signal. Corrosion or performance if it gets into lower shield of damage to wiring could lead to an incorrect sensor.
Page 80 EFI SYSTEM-ECH WITH OXYGEN SENSOR Troubleshooting-Oxygen Sensor (O Condition Possible Cause Conclusion Low voltage output. Shorted sensor or sensor circuit. Replace sensor or repair wiring. Shorted lead wire. Wiring shorted to ground. Contamination of air reference. Remove source of external contamination, protect air reference area.
Page 81 EFI SYSTEM-ECH WITH OXYGEN SENSOR 1. With engine running at idle, listen for a buzzing or Fuel Injectors clicking sound. 2. Disconnect electrical connector from an injector and WARNING listen for a change in idle performance (only running Explosive Fuel can cause ﬁ res and severe on one cylinder) or a change in injector noise or burns.
Page 82 NOTE: If ignition coil(s) are disabled and an ignition pump module and insert pressure test jumper (from fault is registered, system will automatically Kohler EFI Service Kit) between high pressure fuel disable corresponding fuel injector drive line and fuel pump module.
Page 83 Please note vent hose routing and replicate after service or component replacement to prevent pinching or abrasion of vent hoses. Only Kohler replacement parts can be used because ﬁ tting is speciﬁ c to system and must be maintained. Visit KohlerEngines.com for recommended Kohler replacement parts.
Page 84 EFI SYSTEM-ECH WITH OXYGEN SENSOR Troubleshooting Guide Condition Possible Cause Faulty spark plugs. Fuel pump not running. Fuel pressure low. Insuﬃ cient fuel delivery. Engine Starts Hard or Fails to Start TPS set incorrect (ECU Reset and TPS Initialization). When Hot. Crankshaft position sensor loose or faulty.
Page 85 EFI SYSTEM-ECH WITH OXYGEN SENSOR Function Test Fault Codes Example of Diagnostic Display WARNING High Pressure Fluids can puncture skin and cause severe injury or death. One second pause Do not work on fuel system without proper Fault training or safety equipment. Code One second pause Fluid puncture injuries are highly toxic and hazardous.
Page 86 EFI SYSTEM-ECH WITH OXYGEN SENSOR 0230 Fuel Pump Module Circuit Low Voltage or Open 0232 Fuel Pump Module Circuit High Voltage 0336 Crankshaft Position Sensor Noisy Signal 0337 Crankshaft Position Sensor No Signal 0351 Cylinder 1 Ignition Coil Malfunction 0352 Cylinder 2 Ignition Coil Malfunction 0562 System Voltage Low...
Page 87 EFI SYSTEM-ECH WITH OXYGEN SENSOR Code 0107 Code 0113 Component: Manifold Absolute Pressure (MAP or Component: Intake Air Temperature (IAT or TMAP) Sensor TMAP) Sensor Fault: Intake Air Temperature (IAT or TMAP) Fault: MAP or TMAP Circuit Low Voltage or Sensor Circuit High Voltage or Open Open Condition:...
Page 88 EFI SYSTEM-ECH WITH OXYGEN SENSOR Code 0122 Code 0131 Component: Throttle Position Sensor (TPS) Component: Oxygen Sensor Fault: TPS Circuit Low Voltage or Open Fault: O2S 1 Circuit Low Voltage Condition: Open connection, broken wire or faulty Condition: Open connection, broken wire or faulty sensor.
Page 89 EFI SYSTEM-ECH WITH OXYGEN SENSOR Code 0171 Code 0172 Component: Fuel System Component: Fuel System Fault: Maximum adaptation limit exceeded Fault: Minimum adaptation limit exceeded Condition: Fuel inlet screen/ﬁ lter plugged, low Condition: Too high pressure at high pressure fuel pressure at high pressure fuel line, TPS line, TPS malfunction, shorted malfunction, shorted connection, faulty...
Page 90 EFI SYSTEM-ECH WITH OXYGEN SENSOR Code 0174 Code 0202 Component: Fuel System Component: Fuel Injector Fault: Lean fuel condition Fault: Injector 2 Circuit Malfunction Condition: Fuel inlet screen/ﬁ lter plugged, low Condition: Injector damaged or faulty, shorted or pressure at high pressure fuel line, TPS open connection.
Page 91 EFI SYSTEM-ECH WITH OXYGEN SENSOR Code 0336 Code 0352 Component: Crankshaft Position Sensor Component: Ignition Coil Fault: Crankshaft Position Sensor Noisy Signal Fault: Cylinder 2 Ignition Coil Malfunction Condition: Air gap incorrect, loose sensor, faulty/bad Condition: Broken wire in harness (may not be battery, shorted or faulty connection, visible), shorted connection or faulty faulty sensor or faulty sensor grounding.
Page 92 NOTE: MIL is installed by vehicle OEM. Twelve volt (no fuel delivery) supply to bulb will be part of vehicle wire Condition harness. Kohler key switch model will have MIL ● No fuel on engine with 12V supply to bulb. ● Air in high pressure fuel line Conclusion ●...
Page 93 EFI SYSTEM-ECH WITH OXYGEN SENSOR EFI Diagnostic Flow Diagram START OF TEST PROCEED TO START OF TEST FOR RETEST KEY ON MALFUNCTION REFER TO DIAGNOSTIC AID #1 INDICATOR LIGHT SYSTEM POWER REFER TO ARE FAULT CODES DIAGNOSTIC FAULT CODE SUMMARY PRESENT? CLEAR CODES REFER TO DIAGNOSTIC AID #3...
Page 94 FUEL LINE Light (MIL) (if equipped) on equipment control panel, Low permeation fuel line must be installed on all Kohler store fault code in its fault memory, and go into a default Co. engines to maintain EPA and CARB regulatory operating mode.
Page 95 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Wiring harness used in EFI system connects electrical Crankshaft position sensor is essential to engine components, providing current and ground paths for operation; constantly monitoring rotation and speed system to operate. All input and output signaling occurs (RPM) of crankshaft.
Page 96 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Temperature/Manifold Absolute Pressure (TMAP) A high-voltage, solid-state, battery ignition system is sensor is an integrated sensor that checks both intake used with EFI system. ECU controls ignition output and air temperature (IAT) and manifold absolute pressure timing through transistorized control of primary current (MAP).
Page 97 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR High pressure fuel line is an assembly of hoses, injector IMPORTANT NOTES! caps and a fuel connector to fuel pump module. High ● Cleanliness is essential and must be maintained at all pressure fuel line feeds fuel to top of injectors through times when servicing or working on EFI system.
Page 98 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR ELECTRICAL COMPONENTS Grey Connector Side Electronic Control Unit (ECU) Pin # Description Pinout of ECU Not Used Black Connector Side Not Used Pin # Function Malfunction Indicator Light (MIL) Ground Ignition Coil #1 Ground Not Used Battery Ground Not Used Diagnostic Communication Line...
Page 99 ECU Reset Procedure 1. Turn key/ignition OFF. 2. Install Red wire jumper from Kohler EFI service kit on to service port (connect white wire to black wire in 4 way diagnostic port). 3. Turn key/ignition ON, then OFF and count 10 seconds.
Page 100 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR KohlerEngines.com 24 690 01 Rev. S...
Page 101 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR If a computer with diagnostic software is available Crankshaft Position Sensor Observe throttle percent and raw TPS values through A sealed, non-serviceable assembly. If Fault Code diagnostic software. With diagnostic software diagnosis indicates a problem within this area, test and communicating to ECU and key ON engine not running, correct as follows.
Page 102 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR 3. When replacing magnet assembly, alignment is 5. Unplug sensor from wire harness and check sensor critical. There is a D-shaped drive feature on end of resistance separately across pin. Resistance value shaft and a matching pocket in magnet assembly. should again be 1850-2450 Ω.
Page 103 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR If an injector is not operating, it can indicate either a bad Fuel Injectors injector, or a wiring/electrical connection problem. Check as follows: WARNING 1. Disconnect electrical connector from both injectors. Explosive Fuel can cause ﬁ res and severe Plug a 12 volt noid light into one connector.
Page 104 (from disable corresponding fuel injector drive Kohler EFI Service Kit) between high pressure fuel signal. Fault must be corrected to ignition coil line and fuel pump module.
Page 105 Please note vent hose routing and replicate after service or component replacement to prevent pinching or abrasion of vent hoses. Only Kohler replacement parts can be used because ﬁ tting is speciﬁ c to system and must be maintained. Visit KohlerEngines.com for recommended Kohler replacement parts.
Page 106 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Troubleshooting Guide Condition Possible Cause Faulty spark plugs. Fuel pump not running. Fuel pressure low. Insuﬃ cient fuel delivery. Engine Starts Hard or Fails to Start TPS set incorrect (ECU Reset and TPS Initialization). When Hot. Crankshaft position sensor loose or faulty.
Page 107 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Function Test Fault Codes Example of Diagnostic Display WARNING High Pressure Fluids can puncture skin and cause severe injury or death. One second pause Do not work on fuel system without proper Fault training or safety equipment. Code One second pause Fluid puncture injuries are highly toxic and hazardous.
Page 108 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Diagnostic Fault Code Summary Fault Code Connection or Failure Description 0107 Manifold Absolute Pressure (TMAP) Sensor Circuit Low Voltage or Open 0108 Manifold Absolute Pressure (TMAP) Sensor Circuit High Voltage 0112 Intake Air Temperature (TMAP) Sensor Circuit Low Voltage 0113 Intake Air Temperature (TMAP) Sensor Circuit High Voltage or Open 0117...
Page 109 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Diagnostic Code Summary Code 0112 Component: Intake Air Temperature (TMAP) Sensor Code 0107 Fault: Intake Air Temperature (TMAP) Sensor Component: Manifold Absolute Pressure (TMAP) Circuit Low Voltage Sensor Condition: Shorted connection, faulty sensor or Fault: TMAP Circuit Low Voltage or Open shorted wire.
Page 110 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Code 0117 Code 0122 Component: Engine Temperature Sensor Component: Throttle Position Sensor (TPS) Fault: Engine Temperature Sensor Circuit Low Fault: TPS Circuit Low Voltage or Open Voltage Condition: Open connection, broken wire or faulty Condition: Shorted connection, faulty sensor or sensor.
Page 111 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Code 0201 Code 0230 Component: Fuel Injector Component: Fuel Pump Fault: Injector 1 Circuit Malfunction Fault: Circuit Low Voltage or Open Condition: Injector damaged or faulty, shorted or Condition: Shorted or open connection. open connection. Conclusion: Fuel Pump Related Conclusion: Injector Related ●...
Page 112 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR Code 0336 Code 0352 Component: Crankshaft Position Sensor Component: Ignition Coil Fault: Crankshaft Position Sensor Noisy Signal Fault: Cylinder 2 Ignition Coil Malfunction Condition: Air gap incorrect, loose sensor, faulty/bad Condition: Broken wire in harness (may not be battery, shorted or faulty connection, visible), shorted connection or faulty faulty sensor or faulty sensor grounding.
Page 113 NOTE: MIL is installed by vehicle OEM. Twelve volt (no fuel delivery) supply to bulb will be part of vehicle wire Condition harness. Kohler key switch model will have MIL ● No fuel on engine with 12V supply to bulb. ● Air in high pressure fuel line Conclusion ●...
Page 114 EFI SYSTEM-ECH WITHOUT OXYGEN SENSOR EFI Diagnostic Flow Diagram START OF TEST PROCEED TO START OF TEST FOR RETEST KEY ON MALFUNCTION REFER TO DIAGNOSTIC AID #1 INDICATOR LIGHT SYSTEM POWER REFER TO ARE FAULT CODES DIAGNOSTIC FAULT CODE SUMMARY PRESENT? CLEAR CODES REFER TO DIAGNOSTIC AID #3...
Page 115 EFI SYSTEM-BOSCH Gasoline is extremely ﬂ ammable and its vapors can WARNING explode if ignited. Store gasoline only in approved Explosive Fuel can cause ﬁ res and severe containers, in well ventilated, unoccupied buildings, away burns. from sparks or ﬂ ames. Spilled fuel could ignite if it comes in contact with hot parts or sparks from ignition.
Page 116 80°C (176°F) to properly adapt. These adaptive values are maintained as Low permeation fuel line must be installed on all Kohler long as ECU is not reset. Co. engines to maintain EPA and CARB regulatory compliance.
Page 117 EFI SYSTEM-BOSCH ECU requires a minimum of 7.0 volts to operate. Tip of sensor, protruding into exhaust gas, is hollow. Adaptive memory in ECU is operational whenever Outer portion of tip is surrounded by exhaust gas, with required voltage is present, however adapted values inner portion exposed to ambient air.
Page 118 EFI SYSTEM-BOSCH A high-voltage, solid-state, battery ignition system is For starting and warm up, ECU will adjust fuel and used with EFI system. ECU controls ignition output and ignition timing, based upon ambient temperature, engine timing through transistorized control of primary current temperature, and loads present.
Page 119 EFI SYSTEM-BOSCH 2. For plastic-cased ECU’s below 24 584 28-S, system 3. Make sure engine has resistor type spark plugs. can be primed by manually cycling fuel pump. 4. Disconnect main harness connector from ECU. a. Turn key switch to “ON/RUN” position. Fuel pump 5.
Page 120 EFI SYSTEM-BOSCH Throttle Position Sensor (TPS) Throttle Between Resistance Continuity Position Terminals Value (Ω) Closed 2 & 3 800-1200 Closed 1 & 3 1800-3000 Full 2 & 3 1800-3000 Full 1 & 3 800-1200 1 & 2 1600-2500 If resistance values in steps 3, 4, and 5 are within speciﬁ...
Page 121 EFI SYSTEM-BOSCH 7. Locate service connector plug in wiring harness. 6. Run engine at full throttle (above 3000 RPM), to warm up engine and initiate O sensor function in “35 Pin” (MA 1.7) Metal-Cased ECU: Connect a “closed-loop” operation. jumper wire from TPS initialization pin #8 (gray wire) to ground pin (black wire), or use jumper 7.
Page 122 EFI SYSTEM-BOSCH 5. Unplug sensor connector and check sensor b. If voltage is not in speciﬁ ed range, reconnect resistance separately. Resistance value should oxygen sensor lead. With lead connected, probe again be 2375-2625 . or connect sensor connection with red VOA meter lead.
Page 123 EFI SYSTEM-BOSCH 5. With oxygen sensor disconnected and engine not a. Clean connection and check wiring if circuit was running, disconnect main harness connector from not completed. ECU and set meter to Rx1 scale. Check circuit 3. Set meter for DC voltage. Touch red tester lead to continuity as follows.
Page 124 EFI SYSTEM-BOSCH 2. Make sure all safety switch requirements are met. Fuel Injector Details Crank engine and check for ﬂ ashing of test light. Repeat test at other connector. a. If ﬂ ashing occurs, use an ohmmeter (Rx1 scale) and check resistance of each injector across two terminals.
Page 125 EFI SYSTEM-BOSCH 16. Reverse appropriate procedures to install new Injector Inspection Points injector(s) and reassemble engine. Use new O-Rings any time an injector is removed (new replacement injectors include new O-Rings). Lubricate O-Rings lightly with oil. Torque fuel rail and blower housing mounting screws to 3.9 N·m (35 in.
Page 126 EFI SYSTEM-BOSCH 3. Disconnect secondary lead from spark plug. a. If there was no continuity between pump Connect an ohmmeter set on Rx10K scale terminals, replace fuel pump. between spark plug boot terminal and red b. If voltage was below 7, test wiring harness and primary terminal.
Page 127 EFI SYSTEM-BOSCH Internal (In-Tank) Regulator- Idle Speed Screw Dampening Spring Remove screws securing retaining ring and Idle Speed Screw Details regulator in base/holder assembly. Grasp and pull regulator out of base/holder. 5. Always use new O-Rings and hose clamps when installing a regulator.
Page 128 EFI SYSTEM-BOSCH If governor/throttle components are all intact, but you think there may be a problem with adjustment, follow Procedure A to check setting. If governor lever was loosened or removed, go immediately to Procedure B to perform initial adjustment. A.
Page 129 EFI SYSTEM-BOSCH Faulty spark plugs. Fuel pump not running. Fuel pressure low. Insuﬃ cient fuel delivery. Engine starts hard or fails to start TPS oﬀ set incorrect (Initialization). when hot Speed sensor loose or faulty. TPS faulty. Engine temperature sensor faulty. Faulty injectors.
Page 130 EFI SYSTEM-BOSCH “35 Pin” (MA 1.7) Metal-Cased ECU Systems Pin # Component Ignition Coil #1 Not used Engine Speed Sensor ECU Production Test Terminal Not Used Not Used Not Used TPS Initialization Terminal Engine Ground O2 Sensor Not Used Throttle Position Sensor Not Used Oil Temperature Sensor Not Used...
Page 131 EFI SYSTEM-BOSCH 24 690 01 Rev. S KohlerEngines.com...
Page 132 EFI SYSTEM-BOSCH “24 Pin” (MSE 1.0) Plastic-Cased ECU Systems Pin # Component Permanent Battery Voltage Switched Ignition Voltage Safety Switch Throttle Position Sensor (TPS) and Temperature Sensor Ground Not Used Oil Temperature Sensor Input Not Used Throttle Position Sensor (TPS) Input Speed Sensor Input Speed Sensor Ground Oxygen Sensor Input...
Page 133 EFI SYSTEM-BOSCH 24 690 01 Rev. S KohlerEngines.com...
Page 134 EFI SYSTEM-BOSCH “32 Pin” (MSE 1.1) Plastic-Cased ECU Systems Pin # Component Permanent Battery Voltage Switched Battery Voltage TPS Set; “Auto-Learn” Initialization Terminal Throttle Position Sensor (TPS) and Temperature Sensor Ground Not Used Oil Temperature Sensor Input Not Used Throttle Position Sensor (TPS) Input Speed Sensor Input (+) Speed Sensor Ground (-) Not Used...
Page 135 EFI SYSTEM-BOSCH 24 690 01 Rev. S KohlerEngines.com...
Page 136 EFI SYSTEM-BOSCH Fuel System Fault Codes ECU continuously monitors engine operation against preset performance limits. If operation is outside limits, WARNING: Fuel System Under Pressure! ECU activates MIL and stores a diagnostic code in its Fuel system operates under high pressure. System fault memory.
Page 137 EFI SYSTEM-BOSCH Example of Diagnostic Display 1. Diagnostic display initiated through ignition key sequencing. Long Pause Short Pauses Code 32 Long Pause Code 61 Long Pause Light remains on at end of transmission After the problem has been corrected, fault codes may be cleared as follows. 1.
Page 138 EFI SYSTEM-BOSCH "32 Pin" OBD2 "35 Pin" "24 Pin" (MSE P-Code Ap- (MA 1.7) (MSE 1.0) Blink 1.1) plicable to: Connection or Failure Description Metal- Plastic- Note Code Plastic- "32 Pin" (MSE Cased Cased Cased 1.1) ECU/Sys- ECU/ ECU/Sys- ECU/ tem Only System System...
Page 139 EFI SYSTEM-BOSCH "32 Pin" OBD2 "35 Pin" "24 Pin" (MSE P-Code Ap- (MA 1.7) (MSE 1.0) Blink 1.1) plicable to: Connection or Failure Description Metal- Plastic- Code Plastic- Note "32 Pin" (MSE Cased Cased Cased 1.1) ECU/Sys- ECU/ ECU/Sys- ECU/ tem Only System System...
Page 140 EFI SYSTEM-BOSCH Code 22 Code 23 Component: Throttle Position Sensor (TPS) Component: ECU Fault: Unrecognizable signal is being sent from Fault: ECU is unable to recognize or process sensor (too high, too low, inconsistent). signals from its memory. Condition: A “limp-home” operating mode occurs, Condition: Engine will not run.
Page 141 EFI SYSTEM-BOSCH Code 31 Code 32 Component: Fuel Mixture or Oxygen Sensor Component: Oxygen Sensor Fault: System too lean. Oxygen sensor not Fault: No change in sensor output signal. sending expected voltage to ECU. Condition: Open loop operation only, may cause Condition: System operates under “open loop”...
Page 142 EFI SYSTEM-BOSCH Code 33 Code 34 Component: Oxygen Sensor/Fuel System Component: Oxygen Sensor/Fuel System Components Fault: System too rich. Temporary fuel adaptation control is at upper limit. Fault: Long term fuel adaptation control is at upper or lower limit. Condition: Fuel Supply Related (nothing lean–only rich) Condition:...
Page 143 EFI SYSTEM-BOSCH Code 42 Code 43 and 44 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. Component: Engine (Oil) Temperature Sensor Component: TPS “Auto-Learn” initialization function Fault: Not sending proper signal to ECU. failed, throttle angle out of learning range. Condition: Engine may be hard to start because Fault: While performing TPS “Auto-Learn”...
Page 144 EFI SYSTEM-BOSCH Code 51 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. Code 52 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. Component: Injector #1 circuit open, shorted to Component: Injector #2 circuit open, shorted to ground, or shorted to battery. ground, or shorted to battery. Fault: Injector #1 is not functioning because Fault:...
Page 145 EFI SYSTEM-BOSCH Code 56 "32 Pin" (MSE 1.1) Plastic-Cased ECU only. “32 Pin” (MSE 1.1) Plastic-Cased ECU: Pin circuits 29 and 84. Component: Fuel pump relay circuit open, shorted to ground, or shorted to battery. ● Ignition switch Fault: Fuel pump, ignition coils, and fuel ●...
Page 146 EFI SYSTEM-BOSCH ● Code 51-Injector 1, "32 Pin" (MSE 1.1) Plastic- “32 Pin” (MSE 1.1) Plastic-Cased ECU: Circuits Cased ECU only. 28,85, 30, and 87. ● Code 52-Injector 2, "32 Pin" (MSE 1.1) Plastic- ● Relay Cased ECU only. ● ECU grounds ●...
Page 147 EFI SYSTEM-BOSCH 24 690 01 Rev. S KohlerEngines.com...
Page 148 Lubrication System This engine uses a full pressure lubrication system which delivers oil under pressure to crankshaft, camshaft, connecting rod bearing surfaces, and hydraulic valve lifters. A high-eﬃ ciency gerotor oil pump maintains high oil ﬂ ow and oil pressure, even at low speeds and high operating temperatures.
Page 149 Lubrication System CHANGE OIL AND FILTER Testing Change oil while engine is warm. Compressed air, a pressure regulator, pressure gauge, 1. Clean area around oil ﬁ ll cap/dipstick and drain plug. and a continuity tester are required to test switch. Remove drain plug and oil ﬁ...
Page 150 Electrical System BATTERY CHARGING SYSTEM ● Disconnect rectiﬁ er-regulator plug (20/25 amp) or ring terminals (optional high output) and/or wiring harness plug before doing any electric welding on equipment CAUTION powered by engine. Also, disconnect all other Electrical Shock can cause injury. electrical accessories in common ground with engine.
Page 151 Electrical System Condition Conclusion 20/25 amp OK (green) light comes on and stays steady. Disconnect tester black lead attached to 1 AC terminal and reconnect it to other AC terminal. Repeat test. If OK (green) light comes on again, part is good and may be used.
Page 152 Electrical System FUSES 4. Inspect fuse for a solid fusible link or a broken fusible link. Replace fuse if fusible link is broken. If you are This engine has 3 blade type automotive fuses. not sure if fusible link is broken, replace fuse. Replacement fuses must have same rating as blown fuse.
Page 153 Electrical System 40/50 Amp High Output Regulated Charging System Battery Starter Kohler 60-Amp Fuse Rectiﬁ er-Regulator Flywheel Stator 4 Cooling Holes in Stator Wires Assembly Flywheel Stator Stator is mounted on crankcase behind ﬂ ywheel. Follow procedures in Disassembly/Inspection and Service and Reassembly if stator replacement is necessary.
Page 154 Condition Conclusion High Output Charging System adds Voltage is 17 volts AC or Stator is OK. In separate wiring harness Kohler 60-amp Fuse more. Fuse Replacement Voltage is less than 17 Stator is faulty. Continue volts AC. with steps 7 and 8).
Page 155 Electrical System IGNITION SYSTEM Inspection Spark Plug Inspect each spark plug as it is removed from cylinder Spark Plug Component and Details head. Deposits on tip are an indication of general condition of piston rings, valves, and carburetor. Normal and fouled plugs are shown in following photos: Normal Plug taken from an engine operating under normal conditions will have light tan or gray colored deposits.
Page 156 Electrical System Carbon Fouled BATTERY A 12-volt battery with 400 cold cranking amps (cca) is generally recommended for starting in all conditions. A smaller capacity battery is often suﬃ cient if an application is started only in warmer temperatures. Refer to following table for minimum capacities based on anticipated ambient temperatures.
Page 157 Starter System NOTE: Do not crank engine continuously for more than 10 seconds. Allow a 60 second cool down period between starting attempts. Failure to follow these guidelines can burn out starter motor. NOTE: If engine develops suﬃ cient speed to disengage starter but does not keep running (a false start), engine rotation must be allowed to come to a complete stop before attempting to restart engine.
Page 158 Starter System SOLENOID SHIFT ELECTRIC STARTERS Starter Disassembly Solenoid Shift Starter Components NOTE: Do not reuse old retainer. NOTE: Do not soak armature or use solvent when cleaning. Wipe clean using a soft cloth, or use compressed air. 1. Remove nut and disconnect positive (+) brush lead/ bracket from solenoid terminal.
Page 159 Mounting screw 4 brushes and springs are serviced as a set. Use a new Kohler brush and spring kit if replacement is necessary. holes in metal clips must be up/out. Slide brush holder assembly down into place around 1.
Page 160 Starter System b. Position brushes back in their slots so they are ﬂ ush with I.D. of brush holder assembly. Insert brush installation tool (with extension), or use tube described above from a prior brush installation, through brush holder assembly, so holes in metal mounting clips are up/out. c.
Page 161 Disassembly/Inspection and Service WARNING Before working on engine or equipment, disable engine as Accidental Starts can cause severe injury or follows: 1) Disconnect spark plug lead(s). 2) Disconnect death. negative (–) battery cable from battery. Disconnect and ground spark plug lead(s) before servicing.
Page 162 Disassembly/Inspection and Service Clean all parts thoroughly as engine is disassembled. Remove Air Cleaner Assembly (if equipped) Only clean parts can be accurately inspected Heavy Duty Air Cleaner and gauged for wear or damage. There are many 1. Remove nuts securing air cleaner assembly to commercially available cleaners that will quickly remove throttle body.
Page 163 Disassembly/Inspection and Service External Governor Control (ECH EFI) (if equipped) Speed Control Throttle Actuator Cable Clamp Screw Bracket Lever (bottom) Throttle Control Lever Spring Washer Flat Washer (top) Return Spring Remove External Governor Controls (if equipped) 1. Disconnect governor spring attaching governor lever to throttle actuator lever. 2.
Page 164 Disassembly/Inspection and Service Gasoline is extremely ﬂ ammable and its vapors can WARNING explode if ignited. Store gasoline only in approved Explosive Fuel can cause ﬁ res and severe containers, in well ventilated, unoccupied buildings, away burns. from sparks or ﬂ ames. Spilled fuel could ignite if it comes Do not ﬁ...
Page 165 Disassembly/Inspection and Service Remove Fuel Pump Module (ETB ECH EFI & ECH EFI) 1. Remove screws securing fuel pump module to baﬄ e. 2. If engine has a lift fuel pump, inlet fuel line should have been removed from fuel pump, keeping it attached at fuel pump module.
Page 166 Disassembly/Inspection and Service 5. Slide throttle body oﬀ intake manifold. 2. Remove screws securing bracket with fuse and diagnostic caps. Electronic Throttle Body Components (ETB ECH EFI) On oil ﬁ lter side of certain engines, screw closest to exhaust port may also secure engine temperature sensor lead between bracket and baﬄ...
Page 167 Disassembly/Inspection and Service 4. Remove nuts securing rectiﬁ er-regulator bracket and ETB; remove screws securing bracket to engine. Some engines also have a dipstick tube support bracket secured with this bracket on #1 side. Remove screw and clamp securing tube to support bracket.
Page 168 Disassembly/Inspection and Service Engine Temperature Sensor Lead Remove Outer Baﬄ es and Blower Housing NOTE: Some engines may have 2 fuses mounted to a bracket above ECU, and a third in-line fuse by rectiﬁ er-regulator. 1. Disconnect plug from rectiﬁ er-regulator (standard charging system).
Page 169 Disassembly/Inspection and Service Intake Manifold Components (ETB ECH EFI & ECH EFI) MAP or TMAP Fuel Injector Fuel Rail Metal Retaining Clip Sensor Crankshaft Position Crankshaft Position Intake Manifold Sensor (Earlier Sensor (Later ETB Intake Manifold Design Bracket Design Bracket) 1.
Page 170 Disassembly/Inspection and Service Cylinder Head Components Valve Cover Valve Cover Gasket Hex Flange Screw Rocker Arm Pivot Rocker Arm Push Rod Hydraulic Lifter Valve Cap Valve Spring Valve Keeper Valve Spring Valve Seal Retainer Cylinder Head Cylinder Head Valve Dowel Pin Gasket Remove Valve Covers 1.
Page 171 If lifters need to be replaced, apply a liberal and exhaust valves. Use a new seal whenever coating of Kohler lubricant (see Tools and Aids) to base valve is removed or if seal is deteriorated or of each new lifter before it is installed.
Page 172 Disassembly/Inspection and Service After cleaning, check ﬂ atness of cylinder head and Lapping Valves corresponding top surface of crankcase, using a NOTE: Exhaust valves that are black in color cannot be surface plate or precision straight edge and feeler ground and do not require lapping. gauge.
Page 173 Disassembly/Inspection and Service Flywheel Components Flywheel Fan Flywheel Stator Backing Plate 4 Cooling Holes in High Output High Output High Output Charging High Output Charging System Charging System Shim Charging System Flywheel System Stator Baﬄ e Flywheel UP Stamp Remove Fan and Flywheel NOTE: Always use a ﬂ...
Page 174 ﬂ ywheel, crankshaft, and key if ﬂ ywheel key is sheared or keyway is damaged. Inspect ring gear for cracks or damage. Kohler does not provide ring gear as a serviceable part. Replace ﬂ ywheel if ring gear is damaged.
Page 175 Disassembly/Inspection and Service Oil Pump Assembly (Style A) Oil Pump Assembly (Style B) Oil Pump (Style A) Torque Sequence Oil pump is mounted inside closure plate. If service is required, continue with Disassembly, Inspection, and Reassembly. Disassembly 1. Remove screws. 2.
Page 176 Disassembly/Inspection and Service Crankcase Components Closure Plate Gerotor Gears Oil Pump Assembly Closure Plate Seal (Style A) (Style A) (Style A) Governor Shaft Governor Washer Governor Gear Governor Cup Camshaft Connecting Rod Crankshaft Piston (Style B) Piston Pin Retainer Governor Cross Piston Pin Crankcase Clip...
Page 177 Disassembly/Inspection and Service Governor Cross Shaft Oil Seal (if equipped) Piston and Rings Cross Shaft Oil Seal Details Inspection Piston and Rings Components and Details Style A Style B Top Compression Piston Ring Middle Compression Rails Ring 2.0 mm (0.0787 in.) Oil Control Ring Expander Governor Cross Shaft Seal...
Page 178 Disassembly/Inspection and Service speciﬁ c area of piston. Detonation generally occurs from 80 mm bore engines: Top compression ring end gap using low octane fuels. is 0.100/0.279 mm (0.0039/0.0110 in.). Middle compression ring end gap is 1.400/1.679 mm Preignition or ignition of fuel charge before timed spark (0.0551/0.0661 in.).
Page 179 Disassembly/Inspection and Service NOTE: If crankpin is reground, visually check to ensure Connecting Rods ﬁ llet blends smoothly with crankpin surface. Oﬀ set, stepped-cap connecting rods are used in all NOTE: To prevent repeat failures, camshaft and these engines. crankshaft should always be replaced as a set. Inspection and Service Inspect gear teeth of crankshaft.
Page 180 23°-33° Crosshatch NOTE: Kohler pistons are custom-machined to exacting tolerances. When oversizing a cylinder, it should be machined exactly 0.25 mm (0.010 in.) or 0.50 mm (0.020 in.) over new diameter...
Page 181 Disassembly/Inspection and Service Measuring Piston-to-Bore Clearance Piston Detail Style A Style B Model Dimension A Dimension B ECH630-ECH680 6 mm (0.2362 in.) 13 mm (0.5118 in.) ECH730-ECH749 6 mm (0.2362 in.) 6 mm (0.2362 in.) CH26/CH735/ 6 mm (0.2362 in.) 6 mm (0.2362 in.) CH745 NOTE: Do not use a feeler gauge to measure piston-to- bore clearance –...
Page 182 Reassembly Crankcase Components Closure Plate Gerotor Gears Oil Pump Assembly Closure Plate Seal (Style A) (Style A) (Style A) Governor Shaft Governor Washer Governor Gear Governor Cup Camshaft Connecting Rod Crankshaft Piston (Style B) Piston Pin Retainer Governor Cross Piston Pin Crankcase Clip Shaft...
Page 183 Reassembly NOTE: Align chamfer of connecting rod with chamfer of Install Flywheel End Oil Seal its mating end cap. When installed, ﬂ at faces of Oil Seal Detail connecting rods should face each other. Faces with raised rib should be toward outside. 1.
Page 184 Reassembly Clearance Speciﬁ cations-Crankshaft End Play Shims Governor Gear Assembly (if equipped) Green 0.8366-0.9127 mm Governor gear assembly is located inside closure plate. (0.8750 mm/0.034 in. Nominal) If service was required, and governor was removed, Yellow 1.0652-1.1414 mm refer to assembly procedures under Governor Gear (1.1033 mm/0.043 in.
Page 185 Reassembly Install Closure Plate Assembly Install Stator and Backing Plate (ETB ECH EFI & ECH EFI) RTV Must Be All Around O-ring Groove. RTV sealant is used as a gasket between closure plate and crankcase. Refer to Tools and Aids for a listing of approved sealants.
Page 186 Reassembly Install Flywheel CAUTION Using improper procedures can lead to broken fragments. Broken fragments could be thrown from engine. Always Damaging Crankshaft and Flywheel Can observe and use precautions and procedures when cause personal injury. installing ﬂ ywheel. Flywheel Components Flywheel Fan Flywheel Stator...
Page 187 Reassembly 4. Use a ﬂ ywheel strap wrench or holding tool to hold 1. See Servicing Hydraulic Lifters in Disassembly/ ﬂ ywheel. Torque screw securing ﬂ ywheel to Inspection and Service. crankshaft to 71.6 N·m (52.8 ft. lb.). 2. Apply camshaft lubricant to bottom surface of each lifter.
Page 188 Reassembly c. Remove nuts and repeat procedure as required. Valve Stem Seals 4. Check dowel pins are in place and install a new These engines use valve stem seals on intake valves cylinder head gasket (part number facing up). and on exhaust valves. Always use a new seal whenever valve is removed or if seal is deteriorated or damaged in 5.
Page 189 Reassembly Intake Manifold Components (ETB ECH EFI & ECH EFI) MAP or TMAP Fuel Injector Fuel Rail Metal Retaining Clip Sensor Crankshaft Position Crankshaft Position Intake Manifold Sensor (Earlier Sensor (Later ETB Intake Manifold Design Bracket Design Bracket) Install Intake Manifold Install Fuel Injectors NOTE: Ensure all parts are clean, undamaged and free Torque Sequence...
Page 190 Reassembly Install Manifold Absolute Pressure (MAP) Sensor or Install Valve Covers Temperature/Manifold Absolute Pressure (TMAP) Torque Sequence Sensor NOTE: Ensure all parts are clean, undamaged and free of debris and make sure electrical connector has seal in place. 1. Lightly oil MAP or TMAP sensor O-ring and push sensor into bore in intake manifold.
Page 191 Reassembly External Engine Components Debris Screen Blower Housing Outer Baﬄ e Breather Cover Oil Temperature Oil Sentry Inner Baﬄ e Debris Screen Guard Sensor 4. Install inner baﬄ es using remaining screws and Install Breather Cover and Inner Baﬄ es ﬁ...
Page 192 Reassembly Engine Temperature Sensor (Breather Cover) 7. ETB ECH EFI engines with standard charging NOTE: Ensure part is clean, undamaged and free of system, install fuses and diagnostic connector into debris and make sure electrical connector has bracket. seal in place. Install Rectiﬁ...
Page 193 Reassembly Install Metal Debris Screen (if equipped) Install Plastic Debris Screen (if equipped) Place plastic grass screen on fan and secure with hex Spring Washer Details screws. Torque screws to 4.0 N·m (35 in. lb.). Install Debris Screen Guard (if equipped) Position guard on blower housing and secure with screws (and spacers).
Page 194 Reassembly ETB ECH EFI engines with high output charging Install Throttle Body system have black ground lead ring terminal and lock Throttle Body Components (ECH EFI) washer on lower starter screw. Rear Starter Bracket Closure Plate Screw 3. ETB ECH EFI engines equipped with rear starter bracket, secure bracket to closure plate.
Page 195 Reassembly Electronic Throttle Body Components (ETB ECH EFI) Connect Fuses and Install ETB LPAC Support Bracket Diagnostic Fuses Electronic Throttle Connector TPS/ETB Connector Body (ETB) LPAC Support Bracket Screw Vent Hose Breather Hose NOTE: On oil ﬁ lter side of certain engines, screw closest NOTE: Ensure all parts are clean, undamaged and free to exhaust port may also secure engine of debris and make sure electrical connector has...
Page 196 Reassembly Install High Output Charging System Rectiﬁ er- Regulator and Electronic Throttle Body Components (ETB ECH EFI) Wire Tie ETB Rib Retention Teeth 2. Connect TPS/ETB connector. Carefully bend up retention teeth in edge ﬁ xed wire tie and secure to ETB rib.
Page 197 Reassembly Gasoline is extremely ﬂ ammable and its vapors can WARNING explode if ignited. Store gasoline only in approved Explosive Fuel can cause ﬁ res and severe containers, in well ventilated, unoccupied buildings, away burns. from sparks or ﬂ ames. Spilled fuel could ignite if it comes Do not ﬁ...
Page 198 Reassembly ETB ECH EFI ECH EFI 1. Connect electrical connector to ignition coil. 1. Install lift fuel pump (pulse or mechanical) and lines as an assembly. Connect pulse line to crankcase 2. Install fuel pump module baﬄ e to crankcase using vacuum ﬁ...
Page 199 Reassembly Install External Governor Control (ECH EFI) (if equipped) Speed Control Throttle Actuator Cable Clamp Screw Bracket Lever (bottom) Throttle Control Lever Spring Washer Flat Washer (top) Return Spring 1. Install governor lever onto governor cross shaft. 2. Make sure throttle linkage, linkage spring, and black linkage bushing are connected to governor lever and to throttle lever on throttle body.
Page 200 Reassembly WARNING Before working on engine or equipment, disable engine as Accidental Starts can cause severe injury or follows: 1) Disconnect spark plug lead(s). 2) Disconnect death. negative (–) battery cable from battery. Disconnect and ground spark plug lead(s) before servicing. External Engine Components Heavy-Duty Air Low-Proﬁ...
Page 201 Reassembly Install Throttle Control Panel (if equipped) Setting Initial Governor Adjustment (if equipped) NOTE: To identify various parts and assembly of throttle ECH EFI control panel, refer to External Governor Control 1. Move governor lever toward throttle body as far as it Components.
Page 202 Reassembly Install Oil Cooler (if equipped) Sensitivity Adjustment (if equipped) 1. Secure adapter to closure plate with oil ﬁ lter nipple. Torque oil ﬁ lter nipple to 28.5 N·m (21 ft. lb.). 2. Verify all fuel and vent hoses are routed properly and not pinched.
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Kohler Command PRO EFI Service Manual

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