Diagnostic Procedure

1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leak.
3. Check PCV hose connection.

OK or NG

• OK: GO TO 2.
• NG: Discover air leak location and repair.

Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.

OK or NG

• OK (With CONSULT-II): GO TO 3.
• OK (Without CONSULT-II): GO TO  4.
• NG: Repair or replace it.

With CONSULT-II 

1. Perform "POWER BALANCE" in "ACTIVE TEST" mode.
Fig 1: CONSULT-II Active Test Screen Display
Courtesy of NISSAN MOTOR CO., U.S.A.
2. Is there any cylinder which does not produce a momentary engine speed drop?

Yes or No

• Yes: GO TO 4.
• No: GO TO  11.

Stop engine.

1. Disconnect harness connector F44, F101.
2. Turn ignition switch ON.
   Fig 2: Disconnecting Harness Connector F44 & F101

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Check voltage between harness connector F44 terminal 5 and ground with CONSULT-II or tester.
   • Voltage: Battery voltage 
4. Turn ignition switch OFF.
5. Disconnect ECM harness connector.
6. Check harness continuity between harness connector F44 terminal and ECM terminal as follows.

   Refer to WIRING DIAGRAM .

   Fig 3: Checking Harness Continuity Between Harness Connector F44 Terminal & ECM Terminal

   Courtesy of NISSAN MOTOR CO., U.S.A.
   CONNECTOR F44 TERMINAL AND ECM TERMINAL CONNECTION TABLE
   
   

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

   • Continuity should exist. 
7. Also check harness for short to ground and short to power.

OK or NG

• OK: GO TO 5.
• 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 4: F101 Connector Terminals Connection Chart

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

• Operating sound should exist. 

OK or NG

• OK: GO TO 6.
• NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to "INJECTOR CIRCUIT ".
  Fig 5: Checking Function Of Injector-II

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

1. Reconnect all harness connector disconnected.
2. Start engine.
3. Listen to injectors No. 2, No. 4, No. 6 operating sound.
   • Clicking noise should exist. 

OK or NG

• OK: GO TO 7.
• NG: Perform trouble diagnosis for INJECTOR CIRCUIT, refer to "INJECTOR CIRCUIT ".
  Fig 6: Checking Injector-III Operating Sound

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

1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
   NOTE: Do not use CONSULT-II to release fuel pressure, or fuel pressure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
   Fig 7: Removing Fuel Pump Fuse In IPDM E/R

   Courtesy of NISSAN MOTOR CO., U.S.A.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for five seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13-17 mm between the edge of the spark plug and grounded metal portion as shown in the figure.
11. Crank engine for about three seconds, and check whether spark is generated between the spark plug and the grounded metal portion.
    • Spark should be generated. 
    CAUTION:

    • Do not approach to the spark plug and the ignition coil within 50cm. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20kV or more.
    • It might cause to damage the ignition coil if the gap of 17 mm or more is taken.
    Fig 8: Identifying Gap Between Spark Plug Grounded Metal Surface
    Courtesy of NISSAN MOTOR CO., U.S.A.
    NOTE: When the gap is 13 mm or less, the spark might be generated even if the coil is malfunctioning.

OK or NG

• OK: GO TO  11.
• NG: GO TO 8.

1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a known-good spark plug.
3. Crank engine for about three seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.
   • Spark should be generated. 

OK or NG

• OK: GO TO 9.
• NG: Check ignition coil, power transistor and their circuits. Refer to "IGNITION SIGNAL ".

Check the initial spark plug for fouling, etc.

Fig 9: Checking Spark Plug

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

OK or NG

• OK: Replace spark plug(s) with standard type one(s). For spark plug type, refer to "CHANGING SPARK PLUGS (PLATINUM - TIPPED TYPE) ".
• NG:
  1. Repair or clean spark plug.
  2. GO TO 10.

1. Reconnect the initial spark plugs.
2. Crank engine for about three seconds, and recheck whether spark is generated between the spark plug and the grounded portion.
   • Spark should be generated. 

OK or NG

• OK: INSPECTION END 
• NG: Replace spark plug(s) with standard type one(s). For spark plug type, refer to "CHANGING SPARK PLUGS (PLATINUM - TIPPED TYPE) ".

Check compression pressure. Refer to "CHECKING COMPRESSION PRESSURE ".

• Standard: 1, 275 kPa (13.0 kg/cm ²  , 185 psi)/300 RPM 
• Minimum: 981 kPa (10.0 kg/cm ²  , 142 psi)/300 RPM 
• Difference between each cylinder: 98 kPa (1.0 kg/cm ²  , 14 psi)/300 RPM 

OK or NG

• OK: GO TO 12.
• NG: Check pistons, piston rings, valves, valve seats and cylinder head gaskets.

1. Install all removed parts.
2. Release fuel pressure to zero. Refer to "FUEL PRESSURE RELEASE ".
3. Install fuel pressure gauge and check fuel pressure. Refer to "FUEL PRESSURE CHECK ".
   • At idle: Approx. 350 kPa (3.57 kg/cm ²  , 51 psi) 

OK or NG

• OK: GO TO  14.
• NG: GO TO 13.

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.

Check the following items. Refer to "BASIC INSPECTION ".

Fig 10: Ignition Timing Chart

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

OK or NG

• OK: GO TO 15.
• NG: Follow the "BASIC INSPECTION ".

1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
   Fig 11: Disconnecting 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 12: 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 13: 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 16.
• NG: Repair open circuit or short to ground or short to power in harness or connectors.

Refer to "COMPONENT INSPECTION ".

OK or NG

• OK: GO TO 17.
• NG: Replace (malfunctioning) A/F sensor 1.

With CONSULT-II 

Check mass air flow sensor signal 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 

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: GO TO 18.
• 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 items on the rough idle symptom in Symptom Matrix Chart .

OK or NG

• OK: GO TO 19.
• NG: Repair or replace.

Some tests may cause a 1st trip DTC to be set.

Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION ".

• : GO TO 20.

Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

• : INSPECTION END