Heated Exhaust Gas Oxygen (Hego) Sensor Troubleshooting - Kohler KG2204 Service

4.7. Heated Exhaust Gas Oxygen
(HEGO) Sensor
Troubleshooting
Figure 4-14 HEGO Sensor
WARNING
Hot parts can cause severe burns.
Do not touch engine while operating or just after
stopping.
Never operate engine with heat shields or guards
removed.
Servicing the exhaust system. Hot parts can cause
severe injury or death.
Do not touch hot engine parts. The engine and exhaust
system components become extremely hot during
operation.
TP-6903 5/16a
WARNING
Risk of Fire. Can cause severe injury or death.
Do not smoke or permit flames or sparks near fuels or the
fuel system.
Troubleshooting and/or repairing the sensors or the
ECM. A backfire due to an open fuel shut-off valve can
cause severe injury or death. If power is supplied to the
shut-off valve during ECM or sensor troubleshooting, fuel
may enter the air intake manifold or the air cleaner and
cause a backfire. Make sure that the fuel supply is turned
OFF and that the
DISCONNECTED from the power source BEFORE
turning the ECM power on.
Power from
the controller
70K
1
2
HEGO sensor
51A
3
4
51B
To CT sensor
Figure 4-15 HEGO Sensor Wiring Diagram
Refer to Figure 4-15 and follow the steps in the
troubleshooting chart to verify that:

The HEGO sensor is working correctly and is
not damaged.

The sensor leads have continuity (no open
circuits).

The sensor leads are not shorted.
Important: Silicone sprays or inappropriate RTV
(room temperature
contaminate the HEGO sensor. Contaminated HEGO
sensors can produce false or high readings resulting in
poor fuel mixtures and severe performance problems.
Always verify that the sealer is safe to use with the
HEGO sensor before using.
Electrical System and Sensor Troubleshooting
fuel shut-off valves
70J
P26-65, Sensor power
82
P27-82, O2 heater
51
P26-51, Ground
18
P26-18, O2 signal
ECM
vulcanization) sealers
are
can
69