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Home >> Chevrolet >> 1995 >> Corvette ZR-1 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Controls - Tests W/Codes) >> ECM/Pcm Code Charts >> Code P0420, Catalyst SYS, Low O2 Storage Capacity Indicated >> Test Description
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Test Description

WARNING: This page is about a different variant/trim than selected.
NOTE: Test numbers refer to numbers on diagnostic chart.
  1. This chart checks for conditions that can cause 3-way catalytic converter efficiency to appear degraded. Inspect and repair exhaust system as necessary. Also inspect bank 2 sensor No. 2 pigtail and engine harness for any damage that may cause an intermittent fault in high or low oxygen sensor circuit.
  2. If 3-way catalytic converter replacement is necessary, ensure another condition is not present that may have caused catalyst to become damaged (misfire, high engine oil consumption or coolant consumption, retarded spark timing or weak spark). Correct engine misfire or mechanical fault before replacing 3-way catalytic converter to avoid damaging replacement converter.
Fig 1: Code P0420 Schematic (Corvette) Catalyst System, Low Oxygen Storage Capacity Indicated
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Fig 2: Code P0420 Diagnostic Flow Chart (Corvette) Catalyst System, Low Oxygen Storage Capacity Indicated
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