Kohler KG2204 Service page 70

Action
 Check the air-fuel mixer for vacuum leaks.
 Check that air can flow through the air intake duct and that the air
intake duct is undamaged and unrestricted.
 Check that the air filter is clean and undamaged.
 Check that the HEGO sensor is installed securely and that the leads
are not damaged, corroded, or contacting the exhaust manifold or
secondary ignition leads.
 Check that the ECM grounds are clean and tight.
 Inspect the ECM, HEGO sensor, and wire harness connection pins
for damage, corrosion, or contamination.
 Inspect the HEGO sensor for silicon contamination. On the tip of the
sensor that was exposed to the exhaust, check for a white powdery
coating.
 Use Spectrum to check the ECM for additional diagnostic
troubleshooting codes (DTCs).
 Diagnose any other DTCs before proceeding with this chart. Always
repair existing codes starting with the lowest numerical code set first.
Did you find a problem?
 Turn the ECM power OFF.
 Using a DVOM, measure the resistance of the HEGO heater (sensor
side) between pins 1 and 2.
Does the DVOM show a resistance value less than 5 Ohms or greater
than 25 Ohms (resistance should be between 5 and 25 Ohms)?
 Disconnect the wire harness from the ECM
 With the ECM power OFF, check for continuity between the
following:
o P26-18 and HEGO connector pin 4.
o P27-82 and HEGO connector pin 2.
o P26-51 and HEGO connector pin 3.
o P26-65 and HEGO connector pin 1.
Does the DVOM show continuity?
 Connect the wire harness to the ECM.
 With the ECM power turned OFF, disconnect the wire harness from
the HEGO sensor.
 Check for continuity between HEGO connector pin 4 and engine
ground.
Does the DVOM show continuity?
 Turn off the fuel supply and disconnect the power leads to the fuel
shut-off valves to prevent fuel from inadvertently entering the intake
manifold.
 Turn the ECM power ON.
 Check for voltage between HEGO connector pins 3 and 4.
Does Spectrum now show HEGO voltage at less than 0.1 V?
 With the ECM power on and the wire harness disconnected from the
HEGO sensor, check for voltage at the HEGO connector pin 4 and
engine ground
Does the DVOM show above 0.5 V?
 With the ECM power ON, check for voltage between HEGO
connector pins 1 and 2.
Does the DVOM show voltage?
 With the ECM power ON, check for voltage between the HEGO
connector pin 1 and engine ground.
Does the DVOM show voltage?
 With the ECM power ON, check for voltage between the HEGO
connector pin 2 and battery positive.
Does the DVOM show voltage?
70 Electrical System and Sensor Troubleshooting
Yes No
Repair or replace any
damaged Go to the next step.
components.
Replace the HEGO
Go to the next step.
sensor.
Repair any open
circuits as necessary.
Go to the next step.
Repair the signal
shorted to ground Go to the next step.
circuit.
Replace the HEGO
Go to the next step.
sensor.
Repair the circuit short
to voltage as Go to the next step.
necessary.
Verify that the HEGO
sensor is working
Go to the next step.
properly (skip to the
last step).
Repair any open
Go to the next step.
circuits as necessary.
Repair the HEGO
heater ground shorted Go to the next step.
to voltage.
TP-6903 5/16a