Diagnostic Procedure

INSPECTION START
Which malfunction (A or B) is duplicated?

Type A or B
1. A: GO TO 4.
2. B: GO TO 2.
ADJUST THROTTLE POSITION SENSOR
Check the following items. Refer to Basic Inspection .

Fig 1: Item Specification Table
Courtesy of NISSAN MOTOR CO., U.S.A.

GO TO 3.
CHECK INTAKE SYSTEM.
1. Turn ignition switch OFF.
2. Check the following for connection.
  - Air duct
  - Vacuum hoses
  - Intake air passage between air duct to intake manifold collector
OK or NG
1. OK: GO TO 4.
2. NG: Reconnect the parts.
RETIGHTEN GROUND SCREWS
1. Turn ignition switch OFF.
2. Loosen and retighten engine ground screws.
  GO TO 5.
Fig 2: Identifying Engine Ground Location
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK THROTTLE POSITION SENSOR POWER SUPPLY CIRCUIT
1. Disconnect throttle position sensor harness connector.
2. Turn ignition switch ON.
  
  Fig 3: Disconnecting Throttle Position Sensor Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check voltage between sensor terminal 3 and ground with CONSULT-II or tester.
  Voltage: Approximately 5V
OK or NG
1. OK: GO TO 6.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
Fig 4: Checking Voltage Between Sensor Terminal 3 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK THROTTLE POSITION SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between throttle position sensor terminal 1 and engine ground. Refer to Wiring Diagram.
  Continuity should exist.
3. Also check harness for short to power.
OK or NG
1. OK: GO TO 8.
2. NG: GO TO 7.
DETECT MALFUNCTIONING PART
Check the harness for open or short between ECM and throttle position sensor.

Repair open circuit or short to power in harness or connectors.
CHECK THROTTLE POSITION SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 23 and throttle position sensor terminal 2. Refer to Wiring Diagram.
  Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 9.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK THROTTLE POSITION SENSOR
Refer to Component Inspection .

OK or NG
1. OK: GO TO 11.
2. NG: GO TO 10.
ADJUST CLOSED THROTTLE POSITION SWITCH
Adjust closed throttle position switch. Refer to Basic Inspection .

Fig 5: Item Specification Table
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
1. OK: GO TO 11.
2. NG: Replace throttle position sensor. To adjust it, perform Basic Inspection .
CHECK MASS AIR FLOW SENSOR
Refer to Component Inspection .

OK or NG
1. OK: GO TO 12.
2. NG: Replace mass air flow sensor.
CHECK CAMSHAFT POSITION SENSOR
1. Install any parts removed.
2. Start engine.
3. Check voltage between ECM terminals 44, 48 and ground, ECM terminal 49 and ground with DC range.
< Terminal 44 or 48 and engine ground >

Fig 6: Voltage Reference Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 7: Checking Voltage Between ECM Terminals 44, 48 And Ground, ECM Terminal 49 And Ground With DC Range
Courtesy of NISSAN MOTOR CO., U.S.A.

< Terminal 49 and engine ground >

Fig 8: Voltage Reference Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
1. OK: GO TO 13.
2. NG: Replace distributor assembly with camshaft position sensor.
CHECK FUEL INJECTOR
1. Disconnect injector harness connector.
2. Check resistance between terminals as shown in the figure.
  Resistance: 10 - 14Ω [at 25°C (77°F)]
OK or NG
1. OK: GO TO 14.
2. OK: Replace fuel injector.
Fig 9: Checking Resistance Between Terminals
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK INTERMITTENT INCIDENT
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

INSPECTION END.