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Home >> Toyota >> 1998 >> RAV4 Base, 2D Utility, AWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes >> Self-Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold (Except CALIF. Emissions) >> Diagnosis & Repair
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Diagnosis & Repair

  1. Connect scan tool. See Figure. Start and warm engine to normal operating temperature. Raise engine speed 2500-3500 RPM for about 3 minutes. Retrieve codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
  2. If codes other than P0420 are present, diagnose and repair those codes first. If only DTC P0420 is displayed, check exhaust system for leaks. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
  3. Check sensor No. 1. See DTC P0130 : OXYGEN SENSOR CIRCUIT (EXCEPT CALIF. EMISSIONS) test. Repair as necessary. If oxygen circuits are okay, check sensor No. 2 circuits. See DTC P0136 : OXYGEN SENSOR CIRCUIT test. Repair as necessary. If oxygen circuits are okay, replace catalytic converter.
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