NHTSA Complaint #11620052 — 2015 GMC SIERRA 2500

The contact owns a 2015 GMC Sierra 2500. The contact stated that while driving at 45-48 MPH, the check engine warning light illuminated. The contact used a vehicle scanner and retrieved diagnostic test code P0420 that indicated an efficient operating below threshold, and the contact cleared the code. Additionally, the contact stated while the exhaust filter was being cleaned, an unknown message was displayed. Upon clearing the code, the check engine warning light illuminated again. The vehicle was taken to the local dealer, who informed the contact that there was no warranty coverage. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 83,000.