I own 2006 avalanche ltz. Engine light just came on.

Get a computer diagnostics done and it will likely tell you what is wrong. You can buy readers now for less than $100.00. Otherwise you are really guessing.

Did you check the fuses? It could also be a bad connection somewhere in the cab.
If you have had anything like extra speakers, sound system or alarm installed, suspect everything the installers came near.

unhook the batter cable and leave for about five minutes then rehook cable

It is mounted forward of the spare tire.

It's either the sender that's on the rear of the block behind the intake manifold, or a bad connection to it.

If it had four or five prongs coming out of the bottom it is the relay. There should be a part number on it. If there is you can have any parts store cross that number. If not bring it in and they should be able to match it up.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

sounds like a bad oil pressure sending unit. or a bad oil pump would have to check with my tech2 & manual oil pressure gauge to diag.

You can buy one online by following one of the links offered here.

Do you happpen to know what sensor. It has a lot of them. Have you had it scanned? Autozone will do this for free