Diagnostic Procedure

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten engine two screws on the body.
  Refer to "GROUND INSPECTION ".
  
  Fig 1: Locating M28 & M54 Body Ground Screws
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG

OK: GO TO 2.

NG: Repair or replace ground connections.
CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect A/F sensor 1 harness connector.
2. Turn ignition switch ON.
  
  Fig 2: Disconnecting A/F Sensor 1 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check voltage between A/F sensor 1 terminal 3 and ground with CONSULT-II or tester.
  Voltage: Battery voltage
OK or NG

OK: GO TO 4.

NG: GO TO 3.
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 A/F sensor 1 and fuse
  : Repair or replace harness or connectors.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

Turn ignition switch OFF.
Disconnect ECM harness connector.

Check harness continuity between the following terminals. Refer to WIRING DIAGRAM .

ECM TERMINAL REFERENCE

A/F sensor 1 terminal	ECM terminal
1	16
5	35
6	56
2	75

Continuity should exist.

Check harness continuity between ECM terminals 16, 35, 56, 75 or A/F sensor 1 terminals 1, 2, 5, 6 and ground. Refer to WIRING DIAGRAM .
Continuity should not exist.
Also check harness for short to power.

OK or NG

OK: GO TO 5.

NG: Repair open circuit or short to ground or short to power in harness or connectors.

CHECK INTERMITTENT INCIDENT
Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

OK or NG

OK: GO TO 6.

NG: Repair or replace.
REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace air fuel ratio (A/F) sensor 1.
CAUTION:
- Discard any A/F 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 A/F sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897 - 18 or J-43897 - 12 and approved anti-seize lubricant.
  : INSPECTION END