How to repair ecm wiring code p0420

Question

Why does it say repair ecm wiring with code p0420 ? How do I fix this problem ?

Answer 1

HI there

This code isn't normally a wiring issue. This code is for a problem with the catalytic converter on bank 1 of the engine. In most cases the problem is the converter itself, however a bad rear O2 sensor or a poorly tuned engine can cause this code to appear as well.

P0420 GMC - Catalyst System Low Efficiency Bank 1

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