Chevrolet Tahoe 2007
This service light came on 2 weeks ago. The next day, the car seemed to be trying to switch from 2 wheel to 4 wheel drive. Took it to the dealer who found nothing. We drove the car for 2 days without any service lights coming on. Then the switching ( 2 to 4 WD) started again, but this time the transmission would not go above 1st gear. Pulled over and turned off the engine, then tried to restart it. Nothing. Dead. A few minutes later, we go it back home. Had CAA tow it back to the dealer. It’s been a week and they found nothing. They are looking for engine codes that would explain the problem.
Is this an electrical problem or a sensor issue?