Diagnostic Procedure

1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst 1.
   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.

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.

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: Harness Continuity Reference Between Terminals

   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: Harness Continuity Reference Between Terminals

   Courtesy of NISSAN MOTOR CO., U.S.A.
   • Continuity should not exist. 
6. Also check harness for short to power and short to ground.

OK or NG

• OK: GO TO 4.
• NG: Repair open circuit or short to ground or short to power in harness or connectors.

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: Approximately 350 kPa (3.57 kg/cm ²  , 51 psi) 

OK or NG

• OK: GO TO  6.
• NG: GO TO 5.

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.

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 

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 (With CONSULT-II):GO TO 7.
• OK (Without CONSULT-II):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 .

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: Scan Tool Display "Active Test"

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

OK or NG

• OK: GO TO  10.
• NG: Perform trouble diagnosis for INJECTOR CIRCUIT, Refer to "INJECTOR CIRCUIT ".

Without CONSULT-II 

1. Stop engine.
2. Disconnect harness connectors F33, F221
3. Turn ignition switch ON.
   Fig 6: Disconnecting Harness Connectors F33, F221

   Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check voltage between harness connector F33 terminal 5 and ground with CONSULT-II or tester.
   • Voltage: Battery voltage 
5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between harness connector F33 and ECM as follows.

   Refer to WIRING DIAGRAM .

   Fig 7: Harness Connector F33 Terminal 5 & Ground Voltage Test

   Courtesy of NISSAN MOTOR CO., U.S.A.
   CYLINDER, HARNESS CONNECTOR F33 TERMINAL AND ECM TERMINAL
   
   

   Cylinder	Harness connector F33 terminal	ECM terminal
   1	6	23
   2	4	42
   3	2	22
   4	3	41
   5	1	21
   6	7	40

   • Continuity should exist. 
8. 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 ".

Provide battery voltage between harness connector F221 as follows and then interrupt it. Listen to each injector operating sound.

Fig 8: Harness Connector F221 Terminals 4, 3, 2, 1, 7, 6, 5 & Battery Voltage Specifications Table

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