Troubleshooting Flow Chart - Kohler ECV940 Service Manual

Troubleshooting Flow Chart

Following fl ow chart provides an alternative method
of troubleshooting EFI system. Chart will enable you
to review entire system in about 10-15 minutes. Using
chart, accompanying diagnostic aids (listed chart), and
any signaled fault codes, you should be able to quickly
locate any problems within system.
Flow Chart Diagnostic Aids
Diagnostic Aid #1 SYSTEM POWER
(MIL does not illuminate when key is turned ON)
NOTE: MIL is installed by vehicle OEM. Twelve volt
supply to bulb will be part of vehicle wire
harness. Kohler key switch model will have MIL
on engine with 12V supply to bulb.
Conclusion
● Battery
● Main system fuse
● MIL light bulb burned out
● MIL electrical circuit problem
Pin circuits Grey 3.
● Ignition switch
● Permanent ECU power circuit problem
Pin circuit Black 18.
● Switched ECU power circuit problem
Pin circuit Black 15.
● ECU grounds
● ECU
Diagnostic Aid #2 FAULT CODES
Refer to Diagnostic Fault Code Summary.
Diagnostic Aid #3 RUN/ON
(MIL remains ON while engine is running)*
Condition
NOTE: Either incandescent or LED type bulbs can be
used for MIL as long as they do not draw more
than 0.1 amps. Bulb needs to be rated at 1.4
Watts or less, or needs to have a total resistance
of 140 Ω or more. LEDs typically draw less than
0.03 amps.
All current fault codes will turn on MIL when engine is
running.
Diagnostic Aid #4 CRANKSHAFT POSITION SENSOR
(MIL does not turn off during cranking)
Condition
● Crankshaft position sensor
● Crankshaft position sensor circuit problem, pin circuits
Black 4 and Black 13.
● Crankshaft position sensor/toothed wheel air gap
● Toothed wheel
● Flywheel key sheared
● ECU
Diagnostic Aid #5 FUEL PUMP
(fuel pump not turning on)
Condition
● Main fuse
● Fuel pump circuit problem, pin circuits Black 9 and
Grey 17.
● Fuel pump module
62 690 05 Rev. --
Diagnostic Aid #6 IGNITION SYSTEM
(no spark)
Condition
● Spark plug
● Plug wire
● Coil
● Coil circuit(s), pin circuits Grey 10 and Black 1.
● ECU grounds
● ECU
● Vehicle safety interlocks, ground signal on safety wire.
Diagnostic Aid #7 FUEL SYSTEM ELECTRICAL
(no fuel delivery)
Condition
● No fuel
● Air in high pressure fuel line
● Fuel valve shut OFF
● Fuel fi lter/line plugged
● Injector circuit(s), pin circuits Black 5 and Black 6
● Injector
● ECU grounds
● ECU
● Lift pump not working
Diagnostic Aid #8 FUEL SYSTEM
(fuel pressure)
Low Fuel Pressure-Condition
● Low fuel
● Fuel fi lter plugged
● Fuel supply line plugged
● Lift fuel pump - insuffi cient fuel supply
● Fuel pump (lift or module) - internally plugged
Low Fuel Pressure-Condition
● Pressure regulator not functioning properly inside fuel
pump module.
Diagnostic Aid #9 BASIC ENGINE
(cranks but will not run)
Condition
● Refer to basic engine troubleshooting charts within
Troubleshooting, Electronic Fuel Injection System and
Electrical System.
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EFI SYSTEM
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