Diagnostic Procedure

CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten four 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
  
  OK: GO TO 2.
  
  NG: Repair or replace ground connections.
CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
  
  Fig 2: Disconnecting Air Fuel Ratio (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-III or tester.
  Voltage: Battery voltage
  
  Fig 3: Checking Voltage Between A/F Sensor 1 Terminal 3 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  OK or NG
  
  OK: GO TO 4.
  
  NG: GO TO 3.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors M70, F58
- Fuse block (J/B) connector M4
- 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

Turn ignition switch OFF.
Disconnect ECM harness connector.

Check harness continuity between the following terminals.

Refer to Wiring Diagram.

A/F SENSOR 1 AND ECM TERMINALS REFERENCE (1 OF 2)

	A/F sensor 1 terminal	ECM terminal
Bank 1	1	16
	2	75
	5	35
	6	56
Bank 2	1	76
	2	77
	5	57
	6	58

Continuity should exist .

Check harness continuity between the following terminals and ground.

Refer to Wiring Diagram.

A/F SENSOR 1 AND ECM TERMINALS REFERENCE (2 OF 2)

Bank 1		Bank 2
A/F sensor 1 terminal	ECM terminal	A/F sensor 1 terminal	ECM terminal
1	16	1	76
2	75	2	77
5	35	5	57
6	56	6	58

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 A/F SENSOR 1
Replace malfunctioning 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