Kohler Command PRO ECV630 Service Manual page 71

Conclusion: Engine Speed Sensor Related
● Sensor connector or wiring.
● Sensor loose or air gap incorrect.
Speed Sensor Wheel Related
● Damaged teeth.
● Gap section not registering.
Engine Wiring Harness Related
Pin(s) 9 and/or 10 for "24 Pin" (MSE
1.0) Plastic-Cased ECU.
Pin(s) 9 and/or 10 for "32 Pin" (MSE
1.1) Plastic-Cased ECU.
ECU/Harness Related
● ECU-to-harness connection problem.
Code 31
Component: Fuel Mixture or Oxygen Sensor
Fault: System too lean. Oxygen sensor not
sending expected voltage to ECU.
Condition: System operates under open loop control
only. Until fault is detected and registered
by ECU, engine will run rich if oxygen
sensor is shorted to ground or lean if
it is shorted to battery voltage. After
fault is detected, performance can vary,
depending on cause. If performance is
pretty good, problem is probably with
oxygen sensor, wiring, or connectors. If
engine is still running rich (laboring, short
on power) or lean (popping or misfiring),
fuel mixture is suspect, probably incorrect
TPS initialization or low fuel pressure.
TPS Initialization Incorrect
● Lean condition (check oxygen sensor
signal with VOA and see Oxygen
Sensor section).
Engine Wiring Harness Related
● Pin circuit wiring or connectors.
Pin 11 for "24 Pin" (MSE 1.0)
Plastic-Cased ECU.
Pin 20 for "32 Pin" (MSE 1.1)
Plastic-Cased ECU.
Low Fuel Pressure
Oxygen Sensor Related
● Sensor connector or wiring problem.
● Exhaust leak.
● Poor ground path to engine (sensor is
case grounded).
Poor system ground from ECU to engine,
causing rich running while indicating lean.
24 690 02 Rev. D
Code 32
Component: Oxygen Sensor
Fault:
Condition:
Conclusion: Engine Wiring Harness Related
KohlerEngines.com
EFI SYSTEM-BOSCH
No change in sensor output signal.
Open loop operation only, may cause
a drop in system performance and fuel
efficiency.
● Pin circuit wiring or connectors.
Pin 11 for "24 Pin" (MSE 1.0)
Plastic-Cased ECU.
Pin 20 for "32 Pin" (MSE 1.1)
Plastic-Cased ECU.
Oxygen Sensor Related
● Sensor connector or wiring problem.
● Sensor contaminated or damaged.
● Sensor below minimum operating
temperature (375°C, 709°F).
● Poor ground path from sensor to
engine (sensor grounds through shell,
see Oxygen Sensor section).
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