2005 Chevrolet Trailblazer 4.2L, changed all parts for the P0420 code engine light still ON
Hi there,
This code indicates an issue with the catalyst system. Here is a list of all possible causes for this code.
P0420 CHEVROLET - Catalyst System Low Efficiency Bank 1 Read more: https://www.autocodes.com/p0420_chevrolet.html
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