Diagnostic Procedure

CHECK HO2S1 POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 1 harness connector.
3. Turn ignition switch ON.
  
  Fig 1: Disconnecting Heated Oxygen Sensor 1 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check voltage between HO2S1 terminal 3 and ground with CONSULT-II or tester.
  
  Fig 2: Checking Voltage Between HO2S1 Terminal 3 & Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Voltage: Battery voltage
OK or NG
1. OK: GO TO 3.
2. NG: GO TO 2.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M19, E108
- Harness connectors E10, F48
- Fuse block (J/B) connector M1
- 15A fuse
- Harness for open or short between heated oxygen sensor 1 and fuse
  1. Repair harness or connectors.
CHECK HO2S1 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 24 and HO2S1 terminal 2. Refer to WIRING DIAGRAM .
  Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 4.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK HEATED OXYGEN SENSOR 1 HEATER
Refer to "COMPONENT INSPECTION ".

OK or NG
1. OK: GO TO 5.
2. NG: Replace heated oxygen sensor 1.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
1. INSPECTION END