Kohler Command Pro EFI ECH940 Service Manual page 39

6. A special "dry to touch" anti-seize compound is applied to all new oxygen sensors at factory. If recommended
mounting thread sizes are used, this material provides excellent anti-seize capabilities and no additional anti-seize
is needed. If sensor is removed from engine and reinstalled, anti-seize compound should be reapplied. Use an
oxygen sensor safe type anti-seize compound. It should be applied according to directions on label.
Troubleshooting-Oxygen Sensor (O
Condition
Low voltage output.
High voltage output.
Open circuit, no activity from sensor.
Slow time response.
62 690 13 Rev. A
)
2
Possible Cause
Shorted sensor or sensor circuit.
Shorted lead wire.
Wiring shorted to ground.
Contamination of air reference.
Air leak at sensor or gasket, sensor
upper shield damage.
Silica poisoning.
Contaminated gasoline.
Engine problem; misfi re.
Excessive rich air/fuel ratio.
Wiring shorted to voltage.
Broken element .
Sensor dropped.
Hard blow to engine or exhaust
system.
Defective sensor.
Thermal shock.
Open heater circuit.
Improper handling.
Carbon deposits.
Improper fueling.
Incorrect or contaminated fuel.
Excessive engine oil consumption
causing exhaust contamination or
other exhaust side contamination.
Heater circuit open/shorted or out of
specifi cation.
KohlerEngines.com
EFI SYSTEM
Conclusion
Replace sensor or repair wiring.
Remove source of external
contamination, protect air reference
area.
Use recommended torque at
installation, replace gasket or sensor.
Revise application exhaust.
Shield sensor from damage.
Replace sensor.
Use high quality fuel.
Correct cause of misfi re.
Check for high fuel pressure
Leaking injector
Liquid fuel in vent line
Repair wiring.
Replace sensor.
Replace sensor.
Correct fueling.
Use high quality fuel.
Correct engine condition.
Repair short in harness wires, replace
sensor.
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