Diagnostic Procedure

CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
  
  Fig 1: Checking Exhaust Gas Leak
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
- OK: GO TO 2.
- NG: Repair or replace.
CHECK FOR INTAKE AIR LEAK
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
OK or NG
- OK: GO TO 3.
- NG: Repair or replace.
CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
  
  Fig 2: Disconnecting Corresponding A/F Sensor 1 Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals.
  Refer to WIRING DIAGRAM .
  
  Fig 3: Sensor Terminals Reference
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Continuity should exist.
5. Check harness continuity between the following terminals and ground. Refer to WIRING DIAGRAM .
  
  Fig 4: Sensor Terminals Reference
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Continuity should not exist.
6. Also check harness for short to power.
OK or NG
- OK: GO TO 4.
- NG: Repair open circuit or short to ground or short to power in harness or connectors.
CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE ".
2. Install fuel pressure gauge and check fuel pressure. Refer to "FUEL PRESSURE CHECK ".
  At idling: Approx. 350 kPa (3.57 kg/cm ² , 51 psi)
OK or NG
- OK (With CONSULT-II): GO TO 6.
- OK (Without CONSULT-II): GO TO 7.
- NG: GO TO 5.
DETECT MALFUNCTIONING PART
Check the following.
- Fuel pump and circuit (Refer to "FUEL PUMP CIRCUIT ".)
- Fuel pressure regulator (Refer to "FUEL PRESSURE CHECK ".)
- Fuel lines (Refer to CHECKING FUEL LINES )
- Fuel filter for clogging
- : Repair or replace.
CHECK MASS AIR FLOW SENSOR
With CONSULT-II
1. Install all removed parts.
2. Check "MASS AIR FLOW" in "DATA MONITOR" mode with CONSULT-II.
  2.0 - 6.0 g.m/sec: at idling
  
  7.0 - 20.0 g.m/sec: at 2, 500 RPM
OK or NG
- OK: GO TO 8.
- NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to DTC P0101 MAF SENSOR .
CHECK MASS AIR FLOW SENSOR
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
  2.0 - 6.0 g.m/sec: at idling
  
  7.0 - 20.0 g.m/sec: at 2, 500 RPM
OK or NG
- OK (P0171): GO TO 9.
- OK (P0174): GO TO 11.
- NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to DTC P0101 MAF SENSOR .
CHECK FUNCTION OF INJECTOR
With CONSULT-II
1. Start engine.
2. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-II.
3. Make sure that each circuit produces a momentary engine speed drop.
  
  Fig 5: Identifying Consult-II Active Test
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
- OK: GO TO 12.
- NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .

CHECK FUNCTION OF INJECTOR-I

Without CONSULT-II

Stop engine.
Disconnect harness connector F44, F101
Turn ignition switch ON.

Fig 6: Disconnecting Harness Connector
Courtesy of NISSAN MOTOR CO., U.S.A.
Check voltage between harness connector F44 terminal 6 (with triple meters) or 5 (without triple meters) and ground with CONSULT-II or tester.

Fig 7: Checking Voltage Between Harness Connector F44 Terminal 6 Or 5 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

Voltage: Battery voltage
Turn ignition switch OFF

Check harness continuity between harness connector F44 and ECM as follows.

With triple meters

CYLINDER AND TERMINALS REFERENCE

Cylinder	Harness connector F44 terminal	ECM terminal
1	1	23
3	3	22
5	7	21

Without triple meters

CYLINDER AND TERMINALS REFERENCE

Cylinder	Harness connector F44 terminal	ECM terminal
1	6	23
3	2	22
5	1	21

Continuity should exist.

Also check harness for short to ground and short to power.

OK or NG

OK: GO TO 10.
NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .

CHECK FUNCTION OF INJECTOR-II
Provide battery voltage between harness connector F101 as follows and then interrupt it. Listen to each injector operating sound.

Fig 8: Checking Function Of Injector-II
Courtesy of NISSAN MOTOR CO., U.S.A.

With triple meters

Fig 9: Cylinder And Connector Terminals Chart - With Triple Meters
Courtesy of NISSAN MOTOR CO., U.S.A.

Without triple meters

Fig 10: Cylinder And Connector Terminals Chart - Without Triple Meters
Courtesy of NISSAN MOTOR CO., U.S.A.

Operating sound should exist.

OK or NG
- OK: GO TO 12.
- NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
CHECK FUNCTION OF INJECTOR
1. Start engine.
2. Listen to injectors No. 2, No. 4, No. 6 operating sound.
  Clicking noise should exist.
OK or NG
- OK: GO TO 12.
- NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
  
  Fig 11: Checking Function Of Injector
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK INJECTOR
1. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
2. Turn ignition switch OFF.
3. Disconnect all injector harness connectors.
4. Remove injector gallery assembly. Refer to FUEL INJECTOR AND FUEL TUBE .
  Keep fuel hose and all injectors connected to injector gallery.
5. For DTC P0171, reconnect injector harness connectors on bank 1.
  For DTC P0174, reconnect injector harness connectors on bank 2.
6. Disconnect all ignition coil harness connectors.
7. Prepare pans or saucers under each injector.
8. Crank engine for about 3 seconds.
  For DTC P0171, make sure that fuel sprays out from injectors on bank 1.
  
  For DTC P0174, make sure that fuel sprays out from injectors on bank 2.
  
  Fuel should be sprayed evenly for each injector.
OK or NG
- OK: GO TO 13.
- NG: Replace injectors from which fuel does not spray out. Always replace O-ring with new ones.
  
  Fig 12: Checking Injector Spray
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
- : INSPECTION END