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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 386 (ENGINE CONTROLS - SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline) >> Diagnostic Tests >> DTC P0420: TWC System - Low Efficiency - Bank 1 & DTC P0430: TWC System - Low Efficiency - Bank 2 >> Test Description

Test Description

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The numbers below refer to the step numbers in the diagnostic procedure.

  1. 3

    This step inspects for conditions that can cause the 3-way catalytic converter efficiency to appear degraded.

  2. 5

    A catalytic converter which has been discolored may be due to an engine running rich, lean or had a previous sever misfire. Verifying the fuel trim percentages may be of assistance in determining if such a condition exists.

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