LEMON Manuals: Even more car manuals for everyone
Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 39 (Engine Controls - Self-Diagnostics - 1.8L - XE, GXE) >> Diagnostic Tests >> DTC P0420 Or DTC P0430 >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

  1. Check Exhaust System

    Visually check exhaust pipes and muffler for dent. If problem is found, repair as necessary. Perform DTC CONFIRMATION TEST  to verify repair. If problem is not found, go to next step.

  2. Check Exhaust Air Leak

    Start engine. Listen for exhaust air leak before 3-way catalyst. If problem is found, repair as necessary. Perform DTC CONFIRMATION TEST  to verify repair. If problem is not found, go to next step.

  3. Check Intake Air Leak

    Listen for exhaust intake air leak after mass airflow sensor. If problem is found, repair as necessary. Perform DTC CONFIRMATION TEST  to verify repair. If problem is not found, go to next step.

  4. Check Ignition Timing

    Check ignition timing. See ON-VEHICLE ADJUSTMENTS article. If ignition timing is incorrect, adjust as necessary. Perform DTC CONFIRMATION TEST  to verify repair. If ignition timing is okay, go to next step.
    5. CAUTION: DO NOT use ECM ground terminals when measuring voltage.

  5. Check Injector Circuits
    Turn ignition off then on. Measure voltage between ground and ECM terminals No. 101 (Red/Black wire), No. 103 (Yellow/Black wire), No. 105 (Green/Black wire) and No. 107 (Blue/Black wire) by backprobing. See Figure . If battery voltage exists, go to next step. If battery voltage does not exist, repair appropriate injector or circuit as necessary. See SYSTEM & COMPONENT TESTING article. Perform DTC CONFIRMATION TEST  to verify repair.

  6. Check Ignition Spark

    Check for spark at misfiring cylinder(s). If spark is detected, go to next step. If no spark is detected, repair ignition system as necessary. See DTC P0350: IGNITION SIGNAL (PRIMARY) NOT RECEIVED  . Perform DTC CONFIRMATION TEST  to verify repair.
    7. NOTE: After fuel injectors are removed, NEW "O" rings must be used on all fuel injectors before installation.

  7. Check Injectors
    Turn ignition off and allow engine to cool. Ensure no fire hazards exist and remove fuel injector assembly with fuel lines and harness connectors connected. Place a suitable cup under each fuel injector to collect fuel. Disconnect all ignition coil harness connectors. Turn ignition on. Verify fuel is not dripping from fuel injectors. If any injector is dripping, replace fuel injectors which are leaking. Perform DTC CONFIRMATION TEST  to verify repair. If no fuel injectors are leaking, go to next step.

  8. Check For Intermittent

    Check for intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Perform DTC CONFIRMATION TEST  to verify repair.
scientia non olet · About LEMON Manuals