Removal Inspection - Kohler Command Pro ECV850 Service Manual

Removal Inspection

NOTE: Apply anti-seize compound only to threads.
Anti-seize compound will affect sensor
performance if it gets into lower shield of
sensor.
1. If sensor has heavy deposits on lower shield,
engine, oil, or fuel may be source.
2. If heavy carbon deposits are observed, incorrect
engine fuel control may be occurring.
3. If sensor is at room temperature, measure between
signal leads, black wire (Pin C) and grey wire (Pin D)
attached to sensor. If resistance is less than one
megohm, sensor has an internal short.
Troublshooting-Oxygen Sensor (O
Condition
Low voltage output.
High voltage output.
Open circuit, no activity from sensor.
Slow time response.
19 690 01 Rev. --
)
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
4. With sensor at room temperature measure heater
circuit resistance, purple wire (Pin A) and white wire
(Pin B), resistance should be 8.1-11.1 Ω.
5. If a damaged sensor is found, identify root cause,
which may be elsewhere in application. Refer to
Troubleshooting-Oxygen Sensor (O
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.
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.
EFI SYSTEM
) table.
2
Conclusion
35