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
1. OK: GO TO 2.
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
1. OK: GO TO 3.
2. NG: Repair or replace.
CHECK HEATED OXYGEN SENSOR 1 CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect corresponding heated oxygen sensor 1 (HO2S1) harness connector.
  
  Fig 2: Disconnecting Corresponding Heated Oxygen Sensor 1 (Ho2S1) Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal and HO2S1 terminal as follows.
  Refer to WIRING DIAGRAM .
  
  Fig 3: Continuity Between ECM Terminal Reference
  Courtesy of NISSAN MOTOR CO., U.S.A.
  1. Continuity should exist.
5. Check harness continuity between the following terminals and ground.
  Refer to WIRING DIAGRAM .
  
  Fig 4: Continuity Between ECM Terminal Reference
  Courtesy of NISSAN MOTOR CO., U.S.A.
  1. Continuity should not exist.
6. Check harness continuity between HO2S1 terminal 4 and ECM terminal 78.
  1. Continuity should exist.
7. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 4.
2. 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 ".
  1. At idling: 350 kPa (3.57 kg/cm ² , 51 psi)
OK or NG
1. OK: GO TO 6.
2. NG: GO TO 5.
DETECT MALFUNCTIONING PART
Check the following.
- Fuel pump and circuit (Refer to "DTC P1220 FUEL PUMP CONTROL MODULE (FPCM) ", "FUEL PUMP CIRCUIT ".)
- Fuel pressure regulator (Refer to "FUEL PRESSURE CHECK ".)
- Fuel lines (Refer to "CHECKING FUEL LINES ".)
- Fuel filter for clogging
  1. 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.
  1. 3.8 - 5.2 g.m/sec: at idling
  2. 16.0 - 21.5 g.m/sec: at 2, 500 rpm
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in "Service $01" with GST.
  1. 3.8 - 5.2 g.m/sec: at idling
  2. 16.0 - 21.5 g.m/sec: at 2, 500 rpm
OK or NG
1. OK (With CONSULT-II): GO TO 7.
2. OK (Without CONSULT-II): GO TO 8.
3. NG: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. 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: Active Test Display
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 10.
2. NG: Perform trouble diagnosis for "INJECTOR CIRCUIT ".

CHECK FUNCTION OF INJECTOR-I

Without CONSULT-II

Turn ignition switch OFF.
Disconnect harness connectors F21, F201 (bank 1) and F41, F221 (bank 2).

Fig 6: Disconnecting Harness Connectors F21, F201 (Bank 1) And F41, F221 (Bank 2)
Courtesy of NISSAN MOTOR CO., U.S.A.
Turn ignition switch ON.
Check voltage between the following; harness connector F21 terminal 5 and ground, harness connector F41 terminal 5 and ground with CONSULT-II or tester.
1. Voltage: Battery voltage
Turn ignition switch OFF.
Disconnect ECM harness connector.

Check harness continuity between the following terminals.

Fig 7: Checking Voltage Between Connector Terminal

Courtesy of NISSAN MOTOR CO., U.S.A.

CONNECTOR TERMINAL SPECIFICATION

Cylinder	Harness connector terminal	ECM terminal
1	F21 terminal 3	23
3	F21 terminal 2	22
5	F21 terminal 1	21
7	F21 terminal 6	44
2	F41 terminal 3	42
4	F41 terminal 2	41
6	F41 terminal 1	40
8	F41 terminal 6	63

Continuity should exist.

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

OK or NG

OK: GO TO 9.
NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .

CHECK FUNCTION OF INJECTOR-II
Provide battery voltage between the following terminals, and then interrupt it. Listen to each injector operating sound.

Fig 8: Checking Battery Voltage Between Terminals
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 9: Harness Connector Terminals Reference
Courtesy of NISSAN MOTOR CO., U.S.A.
1. Operating sound should exist.
OK or NG
1. OK: GO TO 10.
2. NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to INJECTOR CIRCUIT .
CHECK INJECTOR
1. Turn ignition switch OFF.
2. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
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.
  1. Fuel should be sprayed evenly for each injector.
OK or NG
1. OK: GO TO 11.
2. NG: Replace injectors from which fuel does not spray out. Always replace O-ring with new ones.
Fig 10: Spraying Injector
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
1. INSPECTION END