Service Update 28770 4WD IPS Drift DTC C0398 – 4HI Lock-Up – 2015-2016 Cadillac Chevrolet GMC

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Service Update
28770 4WD IPS Drift DTC C0398 – 4HI Lock-Up
Copyright 2017 General Motors. All Rights Reserved. Page 1 of 2
Reference Number:
N152028770
Release Date:
January 2017
Revision:
00
Attention:
This service update includes vehicles in dealer inventory and customer vehicles that return to the dealership for any reason. This bulletin will expire at the end of the involved vehicle’s New Vehicle Limited Warranty period.
Make
Model
Model Year
RPO
Description
From
To
Cadillac
Escalade / Escalade ESV
2016
2016
NQH
Transfer Case
Chevrolet
Silverado LD
2015
2016
NQH
Transfer Case
Chevrolet
Suburban
2016
2016
NP0/NQH
Transfer Case
Chevrolet
Tahoe
2016
2016
NP0/NQH
Transfer Case
GMC
Sierra LD
2015
2016
NQH
Transfer Case
GMC
Yukon / Yukon XL
2016
2016
NP0/NQH
Transfer Case
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
A “Service 4WD” message may be displayed on the Driver Information Center and DTC C0398 may be set. Concurrently, the vehicle is permanently locked in 4HI and cannot be shifted shift out of it while the code is present. If the code is cleared, this scenario may repeat if the transfer case is in “Auto” mode and driven for approx. 2 or more hours. Customers will likely notice that the steering wheel is harder to turn, the engine will feel like it has lost power and the tires may squeal when turning in a parking lot.
Correction
Dealers are to reprogram the Transfer Case Control Module.
Parts
No parts are required for this repair.
Warranty Information
Labor Operation
Description
Labor Time
Trans. Type
Net Item
9102844
Transfer Case Control Module Reprogramming with SPS
0.4
ZFAT
N/A
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.
 Some modules will require additional programming/setup events to be performed before or after programming.
 Some vehicles may require the use of a CANDi or MDI module for programming.
Service Update
28770 4WD IPS Drift C0398 DTC 4HI Lock-Up
Page 2 of 2
 Review the appropriate service information for these procedures.
 DTCs may set during programming. Clear DTCs after programming is complete.
 Clearing powertrain DTCs will set the Inspection/Maintenance (I/M) system status indicators to NO.
 During the programming procedure, follow the SPS prompts for the correct ignition switch position.
To program a replacement or an existing control module, perform the following procedure:
Important:
 If the vehicle DOES NOT have any service 4 wheel drive messages, continue to step 1.
 If the vehicle has a service 4 wheel drive message and the ONLY “C” code in the transfer case control module is C0398, continue to step 1.
 If there are ANY other “C” codes in the transfer case control module, refer to SI for diagnostics and complete any repairs prior to reprogramming as current diagnostic trouble codes may inhibit the relearn from being completed. If you receive the warranty information after programming, the module has successfully programmed and reprogramming it again will not help the relearn to complete.
1. Access the Service Programming System (SPS) and follow the on-screen instructions.
2. On the SPS Supported Controllers screen, select K69 Transfer Case Control Module-Programming and follow the on-screen instructions. Refer to Transfer Case Control Module Programming and Setup in SI.
3. At the end of programming, clear DTC’s.
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.
GM bulletins are intended for use by professional technicians, NOT a “do-it-yourselfer”. They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the tools, equipment, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your dealer for information on whether your vehicle may benefit from the information.
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GLOBAL SAFETY FIELD INVESTIGATIONS
DCS4305
URGENT – DISTRIBUTE IMMEDIATELY
Date: January 6, 2017
Subject: 28770 – Service Update
4WD IPS Drift DTC C0398 – 4HI Lock-Up
Models: 2016 Cadillac Escalade / Escalade ESV
2016-2015 Chevrolet Silverado LD
2016 Chevrolet Suburban
2016 Chevrolet Tahoe
2016-2015 GMC Sierra LD
2016 GMC Yukon, Yukon XL
Equipped with 4WD Transfer Case (NQH / NP0)
To: All General Motors Dealers
General Motors is releasing Service Update 28770 today. The total number of U.S. vehicles involved is approximately 309,977. Please see the attached bulletin for details.
Global Warranty Management (GWM)
The Investigate Vehicle History (IVH) screen in the GWM system will be updated January 7, 2017. A list of involved vehicles in dealer new inventory is attached to this message. Please hold all warranty transactions until the VIN appears in IVH.
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GLOBAL SAFETY FIELD INVESTIGATIONS

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