Kohler command pro ECH749 Service Manual page 88

EFI SYSTEM-BOSCH
Code 51 "32 Pin" (MSE 1.1) Plastic-Cased ECU only.
Component: Injector #1 circuit open, shorted to
ground, or shorted to battery.
Fault: Injector #1 is not functioning because
the 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 14 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.
● Open 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 either open, or
shorted during engine operation.
Note: after key-off then key-on code
56 would be set also.
ECU Related
● Circuit controlling injector #1 damaged.
● Circuit controlling fuel pump relay
damaged.
88
Code 52 "32 Pin" (MSE 1.1) Plastic-Cased ECU only.
Component: Injector #2 circuit open, shorted to
Fault:
Condition:
Conclusion: Injector Related
Code 55 "32 Pin" (MSE 1.1) Plastic-Cased ECU only.
Component: MIL (Diagnostic lamp) circuit open,
Fault:
Condition:
Conclusion: MIL (diagnostic lamp) Related
KohlerEngines.com
ground, or shorted to battery.
Injector #2 is not functioning because
circuit is open, shorted to ground, or
shorted to battery.
Engine will run very poorly with only one
cylinder functioning.
● 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.
shorted to ground, or shorted to battery.
MIL is not functioning because circuit is
open, shorted to ground, or shorted to
battery.
Engine will run normally if no other errors
are present.
● 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.
24 690 01 Rev. K