Diagnostic Procedure

WARNING: This page is about a different car, the 2004 Nissan Murano. However, it is still accessible from the selected car via links, so may be relevant.

CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dent.

OK or NG
1. OK: GO TO 2.
2. NG: Repair or replace.
CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before the three way catalyst (manifold).
  
  Fig 1: Checking Exhaust Gas Leakage (P0420, P0430)
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 3.
2. NG: Repair or replace.
CHECK INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.

OK or NG
1. OK: GO TO 4.
2. NG: Repair or replace.
CHECK IGNITION TIMING
Check the following items. Refer to "BASIC INSPECTION ".

Fig 2: Ignition Timing Items Specifications (P0420, P0430)
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
1. OK: GO TO 5.
2. NG: Follow the "BASIC INSPECTION ".
CHECK INJECTORS
1. Stop engine and then turn ignition switch ON.
2. Check voltage between ECM terminals 21, 22, 23, 40, 41, 42 and ground with CONSULT-II or tester.
Refer to WIRING DIAGRAM for Injectors .

Battery voltage should exist.

OK or NG
1. OK: GO TO 6.
2. NG: Perform "DIAGNOSTIC PROCEDURE ".
  
  Fig 3: Checking Voltage Between ECM Terminals And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK IGNITION SPARK
1. Turn ignition switch OFF.
2. Disconnect ignition coil assembly from rocker cover.
3. Connect a known-good spark plug to the ignition coil assembly.
4. Disconnect injector harness connectors.
5. Place end of spark plug against a suitable ground and crank engine.
6. Check for spark.
OK or NG
1. OK: GO TO 7.
2. NG: Check ignition coil with power transistor and their circuit. Refer to Refer to "IGNITION SIGNAL ".
  
  Fig 4: Checking Ignition Spark
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK INJECTOR
1. Turn ignition switch OFF.
2. Remove injector assembly.
  Refer to FUEL INJECTOR AND FUEL TUBE .
  
  Keep fuel hose and all injectors connected to injector gallery.
3. Reconnect all injector harness connectors.
4. Disconnect all ignition coil harness connectors.
5. Turn ignition switch ON.
  Make sure fuel does not drip from injector.
OK or NG
1. OK (Does not drip.): GO TO 8.
2. NG (Drips.): Replace the injector(s) from which fuel is dripping.
CHECK INTERMITTENT INCIDENT
Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

Trouble is fixed. INSPECTION END

Trouble is not fixed.: Replace three way catalyst (manifold).