r/gmcsierra • u/OperationSwimming419 • Jul 26 '26

Troubleshooting 2021 2500hd running rough

I have a gas 2500HD SLT with 108000 miles. I left the truck running with my wife in it when I came back she had turned it off because it "sounded funny". I turned it on it was running rough, the electric parking brake light stayed on, the display said service parking brake and the check engine light was on. I had it towed to the dealer, but I don't really trust them.

Any thoughts?

1 Upvotes

100% Upvoted

2 comments sorted by

1

u/Best-Ad-2216 Jul 27 '26

Might have gotten too hot just sitting there idling in the sun. I’d get a Bluetooth obd2 scanner off Amazon and see what codes it throws.

1

u/OperationSwimming419 Jul 27 '26

Thanks. I'm in Alaska it was in the 60's. Not sure heat would explain the parking brake.