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Home >> Nissan-Datsun >> 1998 >> Frontier Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Testing - 2.4 >> Diagnostic Tests >> DTC P0420: 3-Way Catalyst Function >> Procedure

DTC P0420: 3-Way Catalyst Function: Procedure

  1. Inspect exhaust system for damage and repair as necessary. Start engine and run at idle. Check for exhaust leak before three-way catalyst. Check for intake air leak after MAF sensor. Repair or replace faulty components as required. If no leaks are detected, go to next step.
  2. Turn ignition on. Using DVOM, measure voltage between ground and PCM terminals No. 102 (White/Black wire), No. 104 (White/Blue wire), No. 109 (White/Red wire) and No. 111 (White/Purple wire). See Figure. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short in appropriate wire(s) as required.
  3. Disconnect ignition wires from spark plugs individually and connect a known good spark plug to wire. Place spark plug on good ground. Crank engine and check for spark. If spark exists at every plug wire, go to next step. If spark does not exist every plug wire, check and repair spark plug wires, ignition coil and power transistor as necessary. See DTC P1320: IGNITION SIGNAL .
  4. Turn ignition off. Remove injector assembly. Keep all associated fuel lines connected. Disconnect CMP sensor harness connector. Turn ignition on. Verify fuel is not dripping from injectors. Replace injectors which are leaking. If no injectors are faulty, go to next step.
  5. Check ignition timing and adjust as necessary. See ADJUSTMENTS article. Check PCM pins and terminals for damage and check connection of PCM harness connector. Reconnect PCM harness connector and retest. If DTC resets, replace three-way catalyst.
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