Service Update
N192266750 Incorrect Driver Display Message for Diesel Exhaust Fluid
Release Date:
Revision Description:
Attention:

December 2019

Revision:

01

This bulletin has been revised in the warranty information and service procedure
sections. Please discard all previous copies of N192266750.

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
Chevrolet
GMC

Model
Silverado HD
Sierra HD

Model Year
From
To
2020
2020

RPO
L5P

Description
Engine-Diesel, 8 Cyl, 6.6L, DI,
V8, Turbo, Duramax, Gen 5

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

On certain 2020 model year Chevrolet Silverado and GMC Sierra vehicles that are equipped with a 6.6L
diesel engine, may have one or more of the following conditions exist:
1. The instrument panel cluster may incorrectly display the message “DEF Low” when a diesel engine
fluid (DEF) controller internal fault is detected (DTC P20FF), instead of displaying the proper “Service
DEF System” message.
2. The customer may complain of excessive engine fan noise at a low vehicle speed.
3. Under certain conditions, the diagnostic system may set one of the following DTC’s when there is no
problem with a component: (P20EE, P226D, P16F3 and P129F).

Correction

Dealers are to reprogram the engine control module and perform NOx and Catalyst Resets and Regen
Enable.

Parts
No parts are required for this repair.
Warranty Information
Labor
Operation
9104494*
9104598*

Description
Verified Module Software or Calibration Level: Module Is
Programmed with Same Level Software or Calibration
Engine Control Module Reprogramming with SPS (NOX & Catalyst
Resets and Regen Enable) **

Labor
Time
0.2

Trans.
Type
ZFAT

Net
Item
N/A

0.5

* 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.

** Includes NOx and Catalyst reset, Regen Enable and clearing all vehicle DTC’s using GDS2.
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.
2.
3.
4.

Open TIS on the computer used to program the vehicle.
Select and start SPS.
Select Settings.
Select the Warranty Claim Code tab.

Copyright 2019 General Motors. All Rights Reserved.

Page 1 of 3

Service Update
N192266750 Incorrect Driver Display Message for Diesel Exhaust Fluid
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.
Service Procedure
Note: 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.

5164840

Note: If the Same Calibration/Software Warning is noted on the SPS Summary screen, record the warranty claim code
(WCC) and select OK and follow screen instructions. After a successful programming event, the WCC is located in the
Service Programming System dialogue box of the SPS Summary screen. No further action is required. Refer to the
Warranty section of the bulletin.
1.

Reprogram the Engine Control Module. Refer to K20 Engine Control Module: Programming and Setup in SI.
Caution: When performing the crankshaft variation relearn, make sure the steering wheel is straight and no steering input
is being put on the steering wheel. Damage to the power steering pump can be induced if the wheels are turned and the
pump experiences high RPMs.
Caution: Applying the brakes with significant force while revving the engine at high RPMs will damage the power steering
pump.

2.

Using GDS2, navigate to:
•

Module Diagnostics

•

(K20) Engine Control Module

•

Configuration/Reset Functions

•

Reset Functions

•

NOx Sensor 1 Reset- Select “Reset”. No confirmation will happen after selecting reset.

•

Select back once.

•

Select NOx Catalyst Redundant Loading Reset-Select “Reset”. No confirmation will happen after selecting reset.

Page 2 of 3

Service Update
N192266750 Incorrect Driver Display Message for Diesel Exhaust Fluid
•

Select back twice to Control Function

•

Select Particulate Filter Regeneration.

•

Select Particulate Filter Regeneration Enable and select “Enable”. DO NOT perform a service regeneration

•

Clear all DTC’s

5164843

3.

Key off the vehicle FOR GREATER THAN ONE MINUTE to assure all modules completely shut down (sleep). Failure
to allow full sleep cycle will result in malfunction codes to be set with a CEL. Check vehicle for DTC’s P0700 and/or
U0100. Clear codes as required.

4.

On the next key cycle, if the CEL illuminates inspect for DTC’s P0700 and/or U0100. Clear codes as required.

5.

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.

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.

We Support
Voluntary Technician
Certification

Page 3 of 3

GLOBAL SAFETY FIELD INVESTIGATIONS
DCS5244
URGENT - DISTRIBUTE IMMEDIATELY
Date:

December 2, 2019

Subject: N192266750-01 - Service Update
Incorrect Driver Display Message for Diesel Exhaust Fluid
Revised Warranty Information and Service Procedure
Models: 2020 Chevrolet Silverado HD
2020 GMC Sierra HD
Equipped with Engine-Diesel, 8 CYL, 6.6L, Duramax (RPO L5P)
To:

All General Motors Dealers

This bulletin has been revised in the warranty information and service procedure
sections. Please discard all previous copies of N192266750.
END OF MESSAGE
GLOBAL SAFETY FIELD INVESTIGATIONS