Kohler Command PRO ECV630 Service Manual page 74

EFI SYSTEM-BOSCH
Code 52 "32 Pin" (MSE 1.1) Plastic-Cased ECU only.
Component: Injector #2 circuit open, shorted to
ground, or shorted to battery.
Fault: Injector #2 is not functioning because
circuit is open, shorted to ground, or
shorted to battery.
Condition: Engine will run very poorly with only one
cylinder functioning.
Conclusion: Injector Related
● Injector coil shorted or opened.
Engine Wiring Harness Related
● Broken or shorted wire in harness.
ECU pin 15 to injector pin 2. ECU pin
28 to fuel pump relay pin 86. Note:
after key-off then key-on code 56
would be set also. Fuel pump relay pin
87 to injector pin 1.
● Opened main fuse F1.
Fuel Pump Relay Related
● Bad fuel pump relay.
Primary side functional, but pin 30
to pin 87 remains open.
Primary side pin 85 to pin 86 is
open or shorted during engine
operation. Note: after key-off then
key-on code 56 would be set also.
ECU Related
● Circuit controlling injector #2 damaged.
● Circuit controlling fuel pump relay
damaged.
Code 55 "32 Pin" (MSE 1.1) Plastic-Cased ECU only.
Component: MIL (Diagnostic lamp) circuit open,
shorted to ground, or shorted to battery.
Fault: MIL is not functioning because circuit is
open, shorted to ground, or shorted to
battery.
Condition: Engine will run normally if no other errors
are present.
Conclusion: MIL (diagnostic lamp) Related
● MIL element opened or element
shorted to ground.
● Lamp missing.
Engine Wiring Harness Related
● Broken or shorted wire in harness.
ECU pin 29 to lamp open or
shorted.
Vehicle Wiring Harness Related
● Broken or shorted wire in harness.
Power lead to MIL open or shorted.
ECU Related
● Circuit controlling lamp damaged.
74
Code 56 "32 Pin" (MSE 1.1) Plastic-Cased ECU only.
Component: Fuel pump relay circuit open, shorted to
Fault:
Condition:
Conclusion: Fuel Pump Relay Related
Code 61
Component:
Fault:
Condition:
Conclusion:
Troubleshooting Flow Chart
Following flow 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 after 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 in Metal-Cased ECU systems is an LED.
MIL in Plastic-Cased ECU systems must be a
1/4 watt incandescent lamp.
Possible causes:
● Battery
● Main system fuse
● MIL light bulb burned out
● MIL electrical circuit problem
"24 Pin" (MSE 1.0) Plastic-Cased ECU: Pin circuits
19 and 84.
"32 Pin" (MSE 1.1) Plastic-Cased ECU: Pin circuits
29 and 84.
KohlerEngines.com
ground, or shorted to battery.
Fuel pump, ignition coils, and fuel
injectors will not function because fuel
pump relay circuit is either open, shorted
to ground, or may be "on" continuously if
shorted to battery.
Engine will not run, or fuel pump will
continue to run when switch is off.
● Bad fuel pump relay.
Primary side open or shorted.
Fuel Pump Related
● Fuel pump open or shorted internally.
Engine Wiring Harness Related
● Fuel pump fuse F1 open.
● Broken or shorted wire in harness.
ECU pin 28 to fuel pump relay pin
86.
Ignition switch to fuel pump relay
pin 85.
ECU Related
● Circuit controlling fuel pump relay
damaged.
Denotes end of fault codes. If signaled
first, no other fault codes are present.
24 690 02 Rev. D