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Home >> Toyota >> 2000 >> RAV4 Base, AWD, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold (Except CALIF. Emissions) >> Diagnosis & Repair
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Diagnosis & Repair

  1. If any other DTCs are displayed, diagnose and repair those DTCs first. If only DTC P0420 is displayed, go to next step.
  2. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, go to next step.
  3. Check heated oxygen sensor No. 1. See DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT (EXCEPT CALIF. EMISSIONS) . If problem exists, repair as necessary. If problem does not exist, go to next step.
  4. Check heated oxygen sensor No. 2. See DTC P0136: HEATED OXYGEN SENSOR NO. 2 CIRCUIT  test. If problem exists, repair as necessary. If problem does not exist, replace catalytic converter.
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