IPC Gauges Inoperative, Numerous DIC Error Messages, No Brake or Electric Power Steering Assist, Transmission in Default Gear, No Reverse and/or Back Up Lights, No DRL, No Cruise or Adaptive Cruise and/or No Trailer Brake Lights – 2018-2019 Cadillac Chevrolet GMC

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Service Bulletin
Bulletin No.: 20-NA-055
Date: June, 2020

TECHNICAL
Subject: IPC Gauges Inoperative, Numerous DIC Error Messages, No Brake or Electric Power
Steering Assist, Transmission in Default Gear, No Reverse and/or Back Up Lights, No DRL, No Cruise
or Adaptive Cruise and/or No Trailer Brake Lights

Attention: This bulletin is ONLY applicable to the Models, Model Years, equipped with the RPO’s
noted in the table below.

Cadillac

Escalade
Model Year:
from to
2018 2019

2WD/4WD:

All

Engine:

L86

Transmission:

All
Chevrolet

Silverado

Silverado LD Suburban Tahoe
2018 2018
2018 2018
2018 2018
2019 2019
2018 2019
2018 2019
2WD
4WD
4WD
All All All
L83, L86, LV3 L83, LV3
L86 L83, LV3 L83, L86 L83, L86
All MYC M5U
All All All
GMC

Sierra

Sierra Limited
Yukon
2018 2018
2018 2018
2018 2018

2019 2019

2018 2019
2WD
4WD
4WD

All All
L83, L86, LV3 L83, LV3
L86 L83, LV3 L83, L86
All MYC M5U
All All

Involved Region or Country

Condition

Cause Correction

North America, Middle East, Israel, Chile, Columbia, Ecuador, Paraguay, Peru, Uruguay and Thailand.
Some customers may comment on one or more of the following two fault conditions:
1. Aborted Crank:
– Vehicle begins to crank, stops cranking and then has a successful start
2. CAN Lockup:
• IPC gauges inoperative
• Numerous DIC error messages
• Oil pressure gauge reads zero
• Coolant temperature gauge reads zero
• Speedometer gauge reads zero
• Tachometer gauge reads zero
• Fuel gauge reads zero
• Engine appears to be operating in a reduce power mode
• No brake assist
• Possible no electric power steering assist
• Transmission in default gear
• Battery gauges are correct
• No reverse gear and/or no back-up lights
• DRL inoperative
• Numerous DIC error messages displayed
Note: Headlights can be manually turned On.
• Auto headlights inoperative
• The center-stack and radio will be operational
• When the engine is stopped and the HSLAN bus goes to sleep, fault condition is cleared.
Some customers may also comment that the vehicle begins to crank, stops cranking and then has a
successful start.

Note: U0100 alone is not a good indication of this issue. A better indication of the condition are
the symptoms listed above.
If vehicle is left in this condition for an extended period, some technicians may find U0100 (Lost
Communication With Engine Control Module) set.
Some technicians may also find when the engine is stopped and the HSLAN bus goes to sleep, the
fault condition is cleared.
This condition may be caused by a software anomaly.
If you encounter a vehicle with any of the above conditions, reprogram the Engine Control Module
(ECM) with the latest available software.

Service Procedure
Caution: Before downloading the update files, be sure the computer is connected to the internet
through a network cable (hardwired). DO NOT DOWNLOAD or install the files wirelessly. If there is
an interruption during programming, programming failure or control module damage may occur.
Important: Carefully read and follow the instructions below.
• 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. Install a GM Authorized Programming Support Tool to
maintain system voltage. Refer to www.gmdesolutions.com for further information. 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.
• Clear DTCs after programming is complete. Clearing powertrain DTCs will set the Inspection/
Maintenance (I/M) system status indicators to NO.

Important: TIS2WEB screen shown. Techline Connect screen is similar and will be included soon.
Important: If the Same Calibration/Software Warning is noted on the SPS screen, select OK and
follow screen instructions. After a successful programming event, the WCC is located in the Service
Programming

5431207
System dialogue box of the SPS Summary screen. No further action is required. Refer to the Warranty
section of the bulletin.
1. Reprogram the ECM module. Refer to K20 Engine Control Module: Programming and Setup in SI.
Modify as required (e.g., select x module from the controller screen. Then provide step-by-step
instructions or refer to SI procedure.

5431209
Important: TIS2WEB screen shown. Techline Connect screen is similar and will be included soon.
Important: To avoid warranty transaction rejections, you MUST record the warranty claim code
provided on the SPS Warranty Claim Code (WCC) screen on the job card. Refer to callout 1 above for
the location of the WCC on the SPS screen
2. Record SPS Warranty Claim Code on job card for warranty transaction submission.

Parts Information
No parts are required for this repair.

Warranty Information
Federal Select Component Emission Warranty coverage code E2 applies for this module programming
event. This reprogramming is covered for 8 years/ 80,000 miles (U.S.) or 8 years/130,000 km
(Canada).For vehicles repaired under the Emission coverage, use the following labor operation.
Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage
information
Labor Operation
2886718*
Description
Engine Control Module Reprogramming with SPS for Loss of Communication to ECM
Labor Time
0.5 hr

*This is a unique Labor Operation for Bulletin use only.
Important: **To avoid warranty transaction rejections, carefully read and follow the instructions
below:
• The SPS Warranty Claim Code must be accurately entered in the “SPS Warranty Claim Code” field
of the transaction.
• When more than one Warranty Claim Code is generated for a programming event, it is required
to document all Warranty Claim Codes in the “Correction” field on the job card. Dealers must also
enter one of the codes in the “SPS Warranty Claim Code” field of the transaction, otherwise the
transaction will reject. It is best practice to enter the FINAL code provided
by SPS.
Warranty Claim Code Information Retrieval
If the SPS Warranty Claim Code was not recorded on the Job Card, the code can be retrieved in the
SPS system as follows:
1. Open TIS on the computer used to program the vehicle.
2. Select and start SPS.
3. Select Settings.
4. Select the Warranty Claim Code tab.
The VIN, Warranty Claim Code and Date/Time will be listed on a roster of recent programming events.
If the code is retrievable, dealers should resubmit the transaction making sure to include the code
in the SPS Warranty Claim Code field.
Version Modified
2
Released May 04, 2020
Revised June 10, 2020 – Update Condition section.
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 equipment, tools, 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 GM dealer for information on
whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN
CERTIFICATION

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