I Reset the computer in my 1998 Chevy Astro, but even after driving around for a few days and putting it through the GM drive cycle, the OBDII reader is saying that the CAT monitor is not ready. I suspect there is a sensor somewhere that is sending incorrect information to the computer. Is there any way to diagnose this? Or at least a list of the precise conditions that need to be present in order for the CAT test to be completed? Thanks!


Refer to this page for what the PCM is looking for in a full OBDII drive cycle: http://www.obdii.com/drivecycle.html

| improve this answer | |

May require (on some vehicles, I'm not familiar with GM specifically) 15 minutes of steady cruise on the expressway to get all monitors to readiness.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.