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Home >> Nissan-Datsun >> 1998 >> Maxima GLE, RE4F04V >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Testing - 3.0 >> Diagnostic Tests >> DTC P0420: 3-Way Catalyst Function >> Procedure

DTC P0420: 3-Way Catalyst Function: Procedure

  1. Visually inspect exhaust system for damage or leaks. Start engine and run at idle. Check for exhaust leak prior to three way catalyst. Check for intake air leak after MAF sensor. Repair or replace faulty components or repair damage as required. If no problems exist, go to next step.
  2. Turn ignition off. Using DVOM, measure voltage between ground and PCM harness connector terminals No. 102 (Red/Black wire), No. 104 (Red/Yellow wire), No. 106 (Blue/White wire), No. 109 (Red/Green wire), No. 111 (Black/Orange wire) and No. 113 (Purple/Red wire) by backprobing connector. See Figure. If battery voltage exists at each terminal, go to next step. If battery voltage does not exist at any terminal, repair fault in appropriate circuit. See WIRING DIAGRAMS article.
  3. Disconnect ignition coil harness connectors and remove each spark plug coil from rocker covers. Reconnect harness connectors to coils. Connect a known good spark plug to coil and ground spark plug end. Crank engine and check for spark. If spark exists at all coils, go to next step. If spark does not exist at any coil, diagnose fault in coil or coil circuit. See DTC P1320: IGNITION SIGNAL .
  4. Turn ignition off. Reconnect injector harness connectors. Remove injector assembly, keeping fuel hose and all injectors connected. Disconnect CMP sensor harness connector. Turn ignition on. Verify fuel is not dripping from any injectors. Replace any injectors from which fuel is dripping. If all injectors are okay, go to next step.
  5. Disconnect and reconnect harness connectors in circuit. Check PCM pin terminals for damage or corrosion. Reconnect PCM harness connector and retest system. If problems still exist, replace three way catalyst.
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