Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For circuit wiring diagram, see Figure
or Figure
. For connector identification and locations, see CONNECTOR IDENTIFICATION
.
- Retighten Ground Screws
Turn ignition off. Loosen and retighten engine ground screws. See Figure . Go to next step. - Clear Self-Learning Data
Start engine and warm to normal operating temperature.With CONSULT-II
- Select SELF-LEARNING CONT in WORK SUPPORT mode with CONSULT-II.
- Clear self-learning control coefficient by pressing CLEAR or START.
Without CONSULT-II
- Turn ignition off. Disconnect MAF sensor harness connector. See Figure .
- Start engine and let it idle for at least 3 seconds. Stop engine.
- Reconnect MAF sensor. Ensure 1st trip DTC P0102 is displayed. Clear 1st trip DTC.
Run engine for at least 10 minutes at idle speed. If 1st trip DTC P0171 or P0174 is detected and engine is difficult to start, perform diagnosis for DTC P0171 or P0174. See DTC P0171 OR DTC P0174 . If 1st trip DTC P0171 or P0174 is not detected and engine is not difficult to start, go to next step.
- Check Input Signal Circuit
Disconnect appropriate HO2S2 harness connector. See Figure . Disconnect ECM harness connector. See Figure . Check continuity between HO2S2 harness connector terminal No. 1 and ECM harness connector terminal No. 95 (bank 1) or No. 63 (bank 2). See Figure or Figure . Continuity should exist. Also, check harness for short to ground and short to power. If problem is found, repair as necessary. Perform DTC CONFIRMATION TEST to verify repair. If problem is not found, go to next step. - Check Ground Circuit
Check continuity between engine ground and HO2S2 harness connector terminal No. 4. Continuity should exist. Also, check harness for short to power. If problem is found, repair as necessary. Perform DTC CONFIRMATION TEST to verify repair. If problem is not found, go to next step. - Check HO2S2
Start engine and warm to normal operating temperature. Stop vehicle with engine running.With CONSULT-II
- Select FUEL INJECTION in ACTIVE TEST mode. Select HO2S2 (B1) (B2) as the monitor item. Adjust FUEL INJECTION to +25%. HO2S2 (B1) (B2) voltage should be more than .48 volt at least once. Adjust FUEL INJECTION to -25%. HO2S2 (B1) (B2) voltage should be less than .43 volt at least once. If operation is as specified, go to next step. If operation is not as specified, replace HO2S2. Perform DTC CONFIRMATION TEST to verify repair.
Without CONSULT-II
- Measure voltage between engine ground and ECM terminal No. 95 (bank 1) or No. 63 (bank 2) by backprobing. While monitoring voltage, snap throttle to 4000 RPM at least 10 times. Voltage should be more than .48 volt at least once. If voltage is as specified, go to next step. If voltage is not as specified, try the following:
- Snap throttle to 6000 RPM and recheck voltage.
- Let engine idle for 10 minutes and recheck voltage.
- Check voltage while coasting from 50 MPH in 3rd gear.
Voltage should be less than .43 volt at least once. If voltage is not as specified, replace HO2S2. Perform DTC CONFIRMATION TEST to verify repair.
- Check For Intermittent
Check for intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Perform DTC CONFIRMATION TEST to verify repair.