Kohler command pro ECH749 Service Manual page 86

EFI SYSTEM-BOSCH
Code 33
Component: Oxygen Sensor/Fuel System
Fault: System too rich. Temporary fuel
adaptation control is at upper limit.
Condition: Fuel Supply Related (nothing lean–only
rich)
● Restricted return line causing
excessive fuel pressure.
● Fuel inlet screen plugged (in-tank fuel
pump only).
● Incorrect fuel pressure at fuel rail.
Oxygen Sensor Related
● Sensor connector or wiring problem.
● Sensor contaminated or damaged.
● Exhaust leak.
● Poor ground path.
● Pin circuit wiring or connectors.
Pin 10 for "35 Pin" (MA 1.7)
Metal-Cased ECU.
Pin 11 for "24 Pin" (MSE 1.0)
Plastic-Cased ECU.
Pin 20 for "32 Pin" (MSE 1.1)
Plastic-Cased ECU.
TPS Sensor Related
● Throttle plate position incorrectly set or
registered during Initialization.
● TPS problem or malfunction.
Engine Wiring Harness Related
● Difference in voltage between sensed
voltage (pin circuit 17 for metal-cased
ECU, pin circuit 2 for plastic-cased
ECU) and actual injector voltage
(circuit 45/45A).
Systems Related
● Ignition (spark plug, plug wire, ignition
coil.
● Fuel (fuel type/quality, injector, fuel
pump, fuel pressure.
● Combustion air (air cleaner dirty/
restricted, intake leak, throttle bores).
● Base engine problem (rings, valves).
● Exhaust system leak.
● Fuel in crankcase oil.
● Blocked or restricted fuel return circuit
to tank.
ECU/Harness Related
● ECU-to-harness connection problem.
86
Code 34
Component: Oxygen Sensor/Fuel System
Fault:
Condition:
Conclusion: Oxygen Sensor Related
KohlerEngines.com
Components
Long term fuel adaptation control is at
upper or lower limit.
System operates closed loop. No
appreciable performance loss as long
as temporary adaptation can provide
suffi cient compensation.
● Sensor connector or wiring problem.
● Sensor contaminated or damaged.
● Exhaust leak.
● Poor ground path.
● Pin circuit wiring or connectors.
Pin 10 for "35 Pin" (MA 1.7)
Metal-Cased ECU.
Pin 11 for "24 Pin" (MSE 1.0)
Plastic-Cased ECU.
Pin 20 for "32 Pin" (MSE 1.1)
Plastic-Cased ECU.
TPS Sensor Related
● Throttle plate position incorrect during
Initialization procedure.
● TPS problem or malfunction.
Engine Wiring Harness Related
● Difference in voltage between sensed
voltage (pin circuit 17 for metal-cased
ECU, pin circuit 2 for plastic-cased
ECU) and actual injector voltage
(circuit 45/45A).
● Problem in wiring harness.
● ECU-to-harness connection problem.
Systems Related
● Ignition (spark plug, plug wire, ignition
coil.
● Fuel (fuel type/quality, injector, fuel
pressure, fuel pump).
● Combustion air (air cleaner dirty/
restricted, intake leak, throttle bores).
● Base engine problem (rings, valves).
● Exhaust system leak (muffl er, fl ange,
oxygen sensor mounting boss, etc.).
● Fuel in crankcase oil.
● Altitude.
● Blocked or restricted fuel return circuit
to tank.
24 690 01 Rev. K