Test NTC-7B - Checking Oxygen Sensor (O2S) Switching
NOTE:
Perform TEST NTC-1A
before proceeding with this test. For connector terminal identification, see CONNECTOR IDENTIFICATION
at beginning of article. For wiring diagrams, see WIRING DIAGRAMS
at the end of this article. Perform TEST VER-2A
after each repair.
- Allow engine to idle. Inspect engine for any abnormal vacuum condition(s). Repair abnormal vacuum condition(s) as necessary. If no abnormal vacuum condition(s) exist, go to next step.
- Using scan tool, read O2S signal voltage. If voltage is more than 0.1 volt, go to step 4). If voltage is less than 0.1 volt, turn ignition off. Disconnect O2S 4-pin connector and ensure connector is clean and not damaged. Disconnect PCM 60-pin connector and ensure connector is clean and not damaged. Go to next step.
- Using scan tool in ohmmeter mode, check resistance of O2S 4-pin connector terminal No. 2 (harness side), signal circuit (Black/Dark Green wire). If resistance is less than 5 ohms, repair short to ground in O2S signal circuit. If resistance is more than 5 ohms, replace O2S.
- Turn engine off. Replace O2S. Turn ignition on. Using scan tool, reset adaptive fuel memory. Start engine and allow engine to reach normal operating temperature. Using scan tool, read O2S state. If O2S state is switching, repair is complete. If O2S state is not switching, go to TEST NTC-13A .