Diagnostic Procedure

CHECK INTAKE SYSTEM
CHECK THE FOLLOWING FOR CONNECTION.
- Air duct
- Vacuum hoses
OK OR NG
1. OK: GO TO 2.
2. NG: Reconnect the parts.
RETIGHTEN GROUND SCREWS
1. Turn ignition switch off.
2. Loosen and retighten engine ground screws. See Figure .
1. : GO TO 3.
CHECK MAF SENSOR POWER SUPPLY CIRCUIT
1. Disconnect mass air flow (MAF) sensor harness connector.
  
  Fig 1: Disconnecting Mass Air Flow Sensor Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
2. Turn ignition switch on.
3. Check voltage between MAF sensor terminals 2, 4 and ground with CONSULT-II or tester.
  
  Fig 2: Checking Voltage Between MAF Sensor Terminals 2, 4 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK OR NG
1. OK: GO TO 5 .
2. NG: GO TO 4.
DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E15, F18
- Harness for open or short between ECM relay and mass air flow sensor
- Harness for open or short between mass air flow sensor and ECM
1. : Repair harness or connectors.
CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. check harness continuity between MAF sensor terminal 3 and ECM terminal 80.
  Refer to wiring diagram.
  
  Continuity should exist.
4. Also check harness for short to power.
OK OR NG
1. OK: GO TO 6.
2. NG: Repair open circuit or short to power in harness or connectors.
CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between MAF sensor terminal 1 and ECM terminal 62.
  Refer to wiring diagram.
  
  Continuity should exist.
2. Also check harness for short to ground and short to power.
OK OR NG
1. OK: GO TO 7.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 62 (mass air flow sensor signal) and ground.
  
  Fig 3: Check Voltage Between ECM & Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 4: Identifying ECM Voltage Based On Conditions
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. If the voltage is out of specification, disconnect MAF sensor harness connector and connect it again.
OK OR NG
1. OK: GO TO 8.
2. NG: Replace mass air flow sensor.
CHECK INTERMITTENT INCIDENT
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. : INSPECTION END .