P0135 Chevrolet - if all voltage is ok what next

Question

Changed senor and checked voltage o2s1 running is around 800 mv
When off it starts at 450 and goes down under 100 in 90 seconds

Answer 1

Hi there,

This code can be triggered if there's an issue with the PCM. Here is some more info for you.

P0135 CHEVROLET - HO2S Heater Performance Bank 1 Sensor 1

Read more: https://www.autocodes.com/p0135_chevrolet.html