Diagnostic Procedure

INSPECTION START
1. Turn ignition switch OFF.
2. Loosen and retighten engine ground screws. See Figure .
3. Disconnect corresponding heated oxygen sensor 1 harness connector. See Figure and Figure .
1. : GO TO 2.
CHECK HO2S1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal and HO2S1 terminal as follows.
  Refer to Wiring Diagram.
  
  Fig 1: Checking Continuity Between ECM & HO2S1 Terminals
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check harness continuity between ECM terminal or HO2S1 terminal and ground as follows.
  Refer to Wiring Diagram.
  
  Fig 2: Checking Continuity Between ECM Or HO2S1 Terminal & Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. Also check harness for short to power.
  OK or NG
1. OK (With CONSULT-II): GO TO 3.
2. OK (Without CONSULT-II): GO TO 4 .
3. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK HEATED OXYGEN SENSOR 1
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select MANU TRIG and adjust TRIGGER POINT to 100% in DATA MONITOR mode with CONSULT-II.
3. Select HO2S1 (B1)/(B2) and HO2S1 MNTR (B1)/(B2).
4. Hold engine speed at 2,000 rpm under no load during the following steps.
5. Touch RECORD on CONSULT-II screen. See Figure .
6. Check the following.
  - HO2S1 MNTR (B1)/B2) in DATA MONITOR mode changes from RICH to LEAN to RICH more than 5 time in 10 seconds.
    
    Fig 3: DATA MONITOR RICH To LEAN Cycle Display
    Courtesy of NISSAN MOTOR CO., U.S.A.
  - 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. See Figure .
  CAUTION:
  - Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
  - Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
  OK or NG
1. OK: GO TO 5 .
2. NG: Replace malfunctioning heated oxygen sensor 1.
CHECK HEATED OXYGEN SENSOR 1
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 91 (HO2S1 bank 1 signal) (HO2S1 bank 2 signal) and engine ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
  
  Fig 4: Checking Voltage Of Heated Oxygen Sensor 1
  Courtesy of NISSAN MOTOR CO., U.S.A.
  CAUTION:
  - Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
  - Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
  OK or NG
1. OK: GO TO 5.
2. NG: Replace malfunctioning heated oxygen sensor 1.
CHECK INTERMITTENT INCIDENT
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. : INSPECTION END