Diagnostic Procedure

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.

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: Terminals Connection Chart

   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: Terminals Connection Chart

   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.

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: 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.

Check the following.

• Fuel pump and circuit (Refer to "FUEL PUMP CIRCUIT ".)
• Fuel pressure regulator (Refer to "FUEL PRESSURE CHECK ".)
• 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 

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 ".

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 ".

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: CONSULT-II Active Test Screen Display

   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 ".

Without CONSULT-II 

1. Stop engine.
2. Disconnect harness connector F44, F101
3. Turn ignition switch ON.
   Fig 6: Disconnecting Harness Connector F44, F101

   Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check voltage between harness connector F44 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 F44 terminal and ECM terminal as follows.

   Refer to WIRING DIAGRAM .

   ECM AND F44 CONNECTOR TERMINAL CONNECTION TABLE
   
   

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

   Fig 7: Checking Voltage Between Harness Connector F44 Terminal 5 & Ground

   Courtesy of NISSAN MOTOR CO., U.S.A.
   • Continuity should exist. 
8. 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 ".

Provide battery voltage between harness connector F101 as follows and then interrupt it. Listen to each injector operating sound.

Fig 8: F101 Connector Terminals Connection Chart

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