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 ECM Ground Screws On Body
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 2.
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.
  
  Fig 2: Locating A/F Sensor 1 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
2. Turn ignition switch ON.
3. Check voltage between A/F sensor 1 terminal 3 and ground with CONSULT-II or tester.
  1. Voltage: Battery voltage
  Fig 3: Checking Voltage Between A/F Sensor 1 Connector Terminal 3 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 4.
2. 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
  1. : 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 TERMINALS AND A/F SENSOR 1 TERMINALS 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 .
1. 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
1. OK : Replace A/F sensor 1.
2. NG : Repair or replace.