P0420 GMC -

Question

p0420 code engine light on 1997 gmc 1500 5.0 cat has been change 02 sensor bank 1 spider injector also

Answer 1

Hi there,

This code indicates an issue with the catalyst system. Here is a list of possible causes. 

P0420 GMC - Catalyst System Low Efficiency Bank 1

Read more: https://www.autocodes.com/p0420_gmc.html