Engine light...
 

Oil was changed by the dealer a few weeks back, but nothing to report since then.

Hummer has been sitting idle since EOD Wednesday and tonight went out and the engine light came on and stayed on.

Checked the gas cap as I last filled up on Wednesday.

H3 has about 70K on it.

Any idea what I need to look for as an issue?

Los Angeles weather has dropped in temp, but not freezing.

If this happened after the oil change, would think they didn't reset it, etc.

Any help?

Thanks.

What codes is it throwing?

Got no idea. When the CEL illuminates, it is telling you to scan for a code. Without the code(s), guessing which of 1000s of conditions might exist is a waste of time. Go to a local auto parts and have them scan it, report back the code(s) and we would be glad to help.

Does AutoZone do this?

Yes. They do.

This is going to sound stupid, but what do I ask of them?

"I have a check engine light, please read the codes"

Duh, I have OnStar, so I had them run it.

Now, I went to a dealership to get a simple oil change and I should have know better, as this place you bring it in for something simple like brakes or oil and you end up with 5 other issues. I was in a pinch to get the oil change as my usual place is 110 miles away and it has thrown 2 codes:

P0521 Engine Oil Pressure Sensor/Switch Circuit Range/Performance

This code suggests low oil level in the engine, old dirty oil, low oil pressure faulty wiring or connection, faulty oil pressure sender/ sensor.

P0523 Engine Oil Pressure Sensor/Switch Circuit High Voltage

This code suggests various causes, wrong oil used, obstruction in the oil passageway, high pressure because of constriction in this passageway, etc. The vehicle is not to be driven according to what I can find.

I have the oil changed less than 3K miles each time and the service records are aggressive in that anything needed to be done is done well in advance.

My H3 has under 75K miles on it.

So, with this knowledge, the H3 isn't going anywhere other than the shop to correct this.

Anyone have experience with these 2 codes?

Check the oil level. What oil did the dealer use?

Check the actuator and make sure the screens are still in it. Its located right near the front passenger side of engine.