GM has released a new service update for the GMC Sierra HD related to an issue wherein power-retractable assist steps can reverse while deploying or stowing.
The problem: certain units of the GMC Sierra HD may exhibit a condition wherein power-retractable assist steps can suddenly reverse. This condition will occur when the steps are deploying or stowing.
The hazards: the power-retractable assist steps may function incorrectly when deploying or stowing. As a result the steps may stow themselves again partway through deploying, or deploy again partway through stowing.
The fix: to address the issue, GM has instructed dealerships to reprogram the K4 Assist Step Control Module for the power-retractable assist steps. No parts are needed for this service repair. Service is typically completed in approximately 30 minutes.
Affected components: Black power-retractable assist steps with LED lighting (RPO code B3L) or power-retractable assist steps with LED perimeter lighting and bright accent (RPO code BRS).
- 2021 GMC Sierra HD 2500
- 2022 GMC Sierra HD 2500
- 2023 GMC Sierra HD 2500
- 2021 GMC Sierra HD 3500
- 2022 GMC Sierra HD 3500
- 2023 GMC Sierra HD 3500
Number of affected vehicles: GM has not provided an estimated number of affected vehicles.
Owners should: owners can contact GMC directly with any concerns they may have using the contact information listed below.
- GM Service Update number: N222376580
- GMC U.S. Customer Service: 1-800-462-8782
To note, this service update also applies to certain Chevy Silverado HD trucks which have the same issue with incorrectly functioning power-retractable assist steps. The GM Service Update number and the recommended repair is the same for both makes of vehicle.