Three problems related to adaptive cruise control have been reported for the 2021 GMC Sierra 1500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2021 GMC Sierra 1500 based on all problems reported for the 2021 Sierra 1500.
The truck randomly will not detect that it was shifted into park. Shifting between gears and back to park does not automatically fix the the issue and has taken up to 10 mins to turn the truck off. The adaptive cruise controls stopped working and can still use regular cruise control. Just not adaptive. It appears greyed out. The truck has thrown the error code: p1098, engine coolant control valve position sensor minimum stop performance. The truck would go into limp mode until the error was cleared. This error has appeared 4 times over the past five months. The most recent date of it happening was today. 06/30/2026.
Engine burning oil and blowing white smoke out tail pipes. Have to add oil every 1500 miles or sooner if towing. Has been an issue since first oil change. Vehicle is now at 88057 miles.
When using adaptive cruise the brakes have engaged aggressively without cause. This has happened several times prior to my discontinuing the use of this option. I have not had it in for service yet (we just returned from vacation).
| Adaptive Cruise Control problems | |
| Warnings problems | |
| Automatic Emergency Braking problems |