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OnStar Light Red - Service Driver Assist Message - '25 Sierra 1500 Denali Ultimate
I purchased a new '25 Sierra 1500 Denali Ultimate about a month ago. At about 900 miles I got a 'Service Driver Assist' message every time I started the truck, and the Supercruise function would not ...
After 5 or 6 service appointments for the same issue (started in August 2025 with only a couple hundred miles) the dealership provided this information: It is a known issue. GM does not have a repair or correction as of January 9, 2026. There is a Service Bulletin, Preliminary Information - Technical. PIT6455. If there is a resolution, PIT6455 will become a TSB with instructions for the “fix”.