Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
  Refer to "GROUND INSPECTION ".
  
  Fig 1: Checking Ground Connections
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 2.
2. NG: Repair or replace ground connections.
CHECK HO2S2 POWER SUPPLY CIRCUIT
1. Disconnect heated oxygen sensor 2 harness connector.
  
  Fig 2: Disconnecting Heated Oxygen Sensor 2 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
2. Turn ignition switch ON.
3. Check voltage between HO2S2 terminal 3 and ground with CONSULT-II or tester.
  1. Voltage: Battery voltage
OK or NG
1. OK: GO TO 4.
2. NG: GO TO 3.
Fig 3: Checking Voltage Between HO2S2 Terminal 3 & Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E5, F14
- IPDM E/R connector E119
- 10Afuse
- Harness for open or short between heated oxygen sensor 2 and fuse
1. Repair harness or connectors.
CHECK HO2S2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal and HO2S2 terminal as follows. Refer to WIRING DIAGRAM .
  
  Fig 4: ECM Terminal And HO2S2 Terminals
  Courtesy of NISSAN MOTOR CO., U.S.A.
  1. Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 5.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK HEATED OXYGEN SENSOR 2 HEATER
Refer to "COMPONENT INSPECTION ".

OK or NG
1. OK: GO TO 6.
2. NG: Replace malfunctioning heated oxygen sensor 2.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
1. INSPECTION END