TROULE CODE P42

Honda Civic

Tiny

veveya

August, 13, 2006 AT 11:59 PM

1997 honda civic 100040 mileages.
my check engine light was on. The diagnostic trouble code is P0420 Catalyst System Efficiency Below Threshold (Bank 1), one repair technician told me I should replace a new catalyst converter, but another one told me to replace the new O2 sensors, what should I do? Thanks.

FOUND 159 RELATED QUESTIONS

P0420 Cat Converter

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1 Answer

Tiny

Service Writer

August, 14, 2006 AT 10:13 AM

Have someone check the 02 sensor wave patterns on a scope or for being out of spec. In particular the front one. Converter is probably fine, but further testing should be done. If testing was done, not just a conversation, then you'll need to have faith in one of the techs. That code points to bank1-02 sensor. The front sensor evalutes gases before entering the converter and the rear one evaluates it after the converter

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