Cat over temperature protection question

This question is in regards to a 2005 GMC Sierra 5.3L auto.

Is it the downstream O2 sensors that monitor the temp for the CAT over temperature protection function?

No.

O2 sensors do not measure temperature.

The PCM calculates the catalyst temperature based on fueling, timing, torque, load aand a few other things.

Thanks Joe. I just wanted to be sure that with turning off the rear O2's I didn't cause any issues.

Turning off the rear O2S will prevent cat efficiency readiness test from running... but PCM will still calculate cat temperature.

If you are disabling the rear O2's does it make sense to disable cat protection in the ECU?

N ot necessarily, if you are removing teh cats, it would make sense to disable the cat protection protocol.

peace
Hog

My cats are gone, so I will disable the cat protection maps.