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HOMESERVICE MANUALSTOYOTA2000TACOMA BASE, 2D PICKUP, 2.4 L, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM SELF-DIAGNOSTICS - 4-CYLINDERDIAGNOSTIC TESTSDTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (CALIF. EMISSIONS)DIAGNOSIS & REPAIR
2000 Toyota Tacoma Base, 2D Pickup, 2.4 L, Standard

Diagnosis & Repair

2000 Toyota Tacoma Base, 2D Pickup, 2.4 L, StandardSECTION Diagnosis & Repair
  1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. 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 A/F sensor circuits. See DTC P0125: INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL (CALIF. EMISSIONS) . If problem exists, repair as necessary. If problem does not exist, go to next step.
  4. Check heated oxygen sensor No. 2 circuits. See DTC P0136: HEATED OXYGEN SENSOR NO. 2 CIRCUIT . If problem exists, repair as necessary. If problem does not exist, replace catalytic converter.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.