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OBD II Fault Code

  • OBD II P0422

Fault Code Definition
Code P0422 indicates that the Bank 1 Main Catalytic Converter's emissions efficiency has fallen below the minimum allowable limit. This threshold is tracked by a Catalyst Monitoring Oxygen Sensor located on or near the outlet of the Catalytic Converter.

P0422 Symptoms

  • Check Engine Light will illuminate
  • In many cases, no abnormal symptoms may be noticed

Common Problems That Trigger the P0422 Code

  • Defective Catalytic Converter
  • Engine misfires have damaged the Catalytic Converter
  • Internal engine damage resulting in high oil consumption and/or a leaking Head Gasket has damaged the Catalytic Converter

Common Misdiagnoses

  • Oxygen Sensor(s) are replaced when the real problem is a damaged Catalyst
  • Catalyst is replaced when the real problem is internal engine damage, which is producing elevated emissions levels
  • Catalyst is replaced when a misfiring engine is the real problem
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1 User Comment

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By , July 13, 2018
I'm surprised there was no mention of the 02', 03', and 04' transfer case problems for Yukons and Tahoes. There should have been a recall.