Kohler Command PRO ECH630 Service Manual page 47

Oxygen Sensor Symptoms and Corrections
CONDITION
Low voltage output
High voltage output
Open circuit, no activity from
sensor
Slow time response
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
Section 5
EFI Fuel System
CORRECTION
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
Correct air/fuel ratio
Repair wiring
Replace sensor
Replace sensor
Correct fueling
Use high quality fuel
Correct engine condition
Repair short in harness wires,
replace sensor
5
5.15