Technical Service Bulletin PI1154 — 2013 GMC SIERRA 1500

Delayed 1-2 Upshift While Driving at or Below 15 Percent Throttle Condition/Concern Some customers may comment that during the first few launches after a key cycle, they experience a delayed 1-2 upshift. If the vehicle has no diagnostic codes, the delay in the 1-2 shift may be driver induced. If the vehicle has diagnostic codes, address these diagnostic codes prior to using this bulletin. On a level surface if the vehicle is launched from a stop at light throttle (less than 15%), then the throttle is closed before reaching 16 km/h (10 mph), then the throttle is opened and held to less than 15%, there could be a 1-2 upshift delay. This delay will last until the vehicle exceeds 24 km/h (15 mph) or the driver drops back to closed throttle.