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 Fig 1
or Fig 2
. For connector identification and locations, see CONNECTOR IDENTIFICATION
.
- Retighten HO2S1
Turn ignition off. Disconnect appropriate HO2S1 harness connector. See Figure . Loosen and retighten HO2S1 to 30-44 ft. lbs. (40-60 N.m). Go to next step. - Check Input Signal Circuit
Disconnect ECM harness connector. See Figure . Check continuity between HO2S1 harness connector terminal No. 2 and ECM harness connector terminal No. 94 (on bank 1) or No. 62 (on bank 2). See Fig 1 or Fig 2 . 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 HO2S1 harness connector terminal No. 4 (Black wire). 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 Harness Connector
Inspect HO2S1 connectors for water. If water exists, repair or replace harness or connector. Perform DTC CONFIRMATION TEST to verify repair. If water does not exist, go to next step. - Check HO2S1
Reconnect all harness connectors. Start engine and warm to normal operating temperature.With CONSULT-II
- Select MANU TRIG, and adjust TRIGGER POINT to 100% in DATA MONITOR mode with CONSULT-II. Select HO2S1 (B1)/(B2) and HO2S1 MNTR (B1)/(B2). Hold engine speed at 2000 RPM. Press RECORD. The following should occur:
- HO2S1 MNTR (B1)/(B2) changes from RICH to LEAN to RICH 5 times in 10 seconds.
- HO2S1 (B1)/(B2) voltage goes above 0.6V at least once.
- HO2S1 (B1)/(B2) voltage goes below 0.3V at least once.
- HO2S1 (B1)/(B2) voltage never exceeds 1.0V.
Without CONSULT-II
- Measure voltage between ground and ECM terminal No. 94 (bank 1) or No. 62 (bank 2) by backprobing. Increase engine speed to 2000 RPM. The following should occur:
- Voltage should cycle from less than .3 volt to more than .6 volt and back more than 5 times within 10 seconds.
- Maximum voltage should be more than .6 volt at least once.
- Minimum voltage should be less than .3 volt at least once.
- Voltage should never exceed one volt.
If operation is as specified, go to next step. If operation is not as specified, replace HO2S1. Perform DTC CONFIRMATION TEST to verify repair.
- Select MANU TRIG, and adjust TRIGGER POINT to 100% in DATA MONITOR mode with CONSULT-II. Select HO2S1 (B1)/(B2) and HO2S1 MNTR (B1)/(B2). Hold engine speed at 2000 RPM. Press RECORD. The following should occur:
- Check For Intermittent
Check for intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Perform DTC CONFIRMATION TEST to verify repair.