Service Update 17419 Transmission Rough Upshifts – 2018 Chevrolet Silverado & GMC Sierra

SEOCONTENT-START

Service Update
17419 Transmission Rough Upshifts

Make	Model	Model Year		RPO	Description
		From	To
Chevrolet	Silverado	2018	2018	L5P MW7	Engine-Diesel, 6.6L Transmission – 6-speed, Allison
GMC	Sierra

Involved vehicles are marked “open” on the Investigate Vehicle History screen in GM Global Warranty Management system.  This site should always be checked to confirm vehicle involvement prior to beginning any required inspections and/or repairs.   

Condition	Certain 2018 model year Chevrolet Silverado HD and GMC Sierra HD vehicles, equipped with 6.6L diesel engine (RPO L5P) and Allison transmission (RPO MW7), may have a condition in which the automatic transmission has rough upshifts.
Correction	Reprogram the transmission control module (TCM).

Parts

No parts are required for this repair.

Warranty Information

* To avoid warranty transaction rejections, the SPS Warranty Claim Code must be entered when submitting this transaction.

** SPS Warranty Claim Code is NOT required when submitting this transaction.

Service Procedure

Note: Carefully read and follow the instructions below.

• DO NOT attempt to order the calibration number from GM Customer Care and Aftersales. The calibration numbers required for this service procedure are programmed into control modules via a Multiple Diagnostic Interface (MDI) with the calibration update.  If you cannot access the calibration, call the Techline Customer Support Center and it will be provided.
• DO NOT program a control module unless directed to by a service procedure or a service bulletin. If the control module is not properly configured with the correct calibration software, the control module will not control all of the vehicle features properly.
• Ensure the programming tool is equipped with the latest software and is securely connected to the data link connector. If there is an interruption during programming, programming failure or control module damage may occur.
• Stable battery voltage is critical during programming. Any fluctuation, spiking, over voltage or loss of voltage will interrupt programming. When required install the EL-49642 SPS Programming Support Tool to maintain system voltage. If not available, connect a fully charged 12 V jumper or booster pack disconnected from the AC voltage supply. DO NOT connect a battery charger.
• Turn OFF or disable systems that may put a load on the vehicles battery such as; interior lights, exterior lights (including daytime running lights), HVAC, radio, etc.
• During the programming procedure, follow the SPS prompts for the correct ignition switch position.
• Clear DTCs after programming is complete. Clearing powertrain DTCs will set the Inspection/Maintenance (I/M) system status indicators to NO.
• Refer to K71 Transmission Control Module: Programming and Setup for additional information on programming.

Note: If the Same Calibration/Software Warning is noted on the SPS Controller screen, do NOT attempt to program the module. No further action is required. Refer to the Warranty section of the bulletin and use labor operation code 9103485, Module Programming Not Required.

Important: It is important that these vehicles have both the transmission control module (TCM) programmed, per this service update, as well as the engine control module (ECM) programmed, per emission recall 17337, at the same time.  Failure to perform both field actions at the same time on these vehicles may result in complaints of poor drivability.

1. Reprogram the transmission control module. Refer to K71 Transmission Control Module: Programming and Setup in SI.
2. Record SPS Warranty Claim Code on job card for warranty transaction submission.

Dealer Responsibility

Whenever a vehicle subject to this service update enters your vehicle inventory, or is in your facility for service in the future, and the vehicle is still covered under the New Vehicle Limited Warranty, you must take the steps necessary to be sure the service update correction has been made before selling or releasing the vehicle.

All new, used, GM Certified Used, courtesy transportation vehicles, dealer shuttle vehicles, etc. in dealers’ possession and subject to this bulletin must be held and inspected/repaired per the service procedure of this bulletin before customers take possession of these vehicles.  Involved vehicles must be held and not delivered to customers, dealer-traded, released to auction, used for demonstration, or any other purpose.

All GM Certified Used vehicles currently in the dealers’ inventory within the Certified Pre-Owned Inventory System (CPOIS) will be de-certified and must be held and remedied per the service procedure in this bulletin.  Upon submitting an accepted/paid warranty transaction in the Global Warranty Management (GWM) system, the vehicle can be re-certified for sale within the CPOIS system, or once again be used in the CTP program.