Test Step 4 - O2 Sensor Test
- Turn the ignition off.
NOTE:
Check for contaminants that may cause improper O2 sensor operation, such as contaminated fuel, unapproved silicone, or evidence of oil or coolant.
- Disconnect the O2 sensor harness connector.
- Turn the ignition on.
- With a scan tool, monitor the O2 sensor voltage.
NOTE:
The voltage should be approximately 5.0 volts with the connector disconnected.
- Connect a jumper wire between the signal circuit and the return circuit in the O2 sensor harness connector.
NOTE:
The voltage should drop from 5.0 volts to 2.5 volts with the jumper wire in place.
Is the O2 sensor voltage displayed on the scan tool as described?
Yes
- Replace the O2 sensor. Refer to FOR ENGINE CJRA - REMOVAL AND INSTALLATION , FOR ENGINE CGVA - REMOVAL AND INSTALLATION or FOR ENGINE CGUA - REMOVAL AND INSTALLATION .
- Perform the PCM Verification Test. Refer to PCM VERIFICATION TEST .
No
- Go to Test Step TEST STEP 5 - O2 SENSOR SIGNAL CIRCUIT .