Information on Diesel Exhaust Fluid Pump is Unable to Build Pressure After Replacement – 2017-2022 Cadillac Chevrolet GMC

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Service Bulletin Bulletin No.: 20-NA-110
Date: August, 2021
INFORMATION
Subject: Information on Diesel Exhaust Fluid (DEF) Pump Unable to Build Pressure After
Replacement
Attention: Only perform this procedure after replacing the DEF pump and the system does not
build pressure (does not prime).
Brand: Model:
Model Year: VIN: Engine:
(Diesel)
Transmission:
from to from to
Cadillac Escalade Models 2021 2022
— —
LM2
—
Chevrolet
Colorado 2016 2021 LWN
Cruze 2017 2020 LH7
Express 2017 2021 LWN
Equinox 2018 2019 LH7
Silverado 2017 2018 L5P
Silverado 1500 (New
Model-12th VIN=7) 2019 2019 LM2
Silverado 1500 2020 2021 LM2
Silverado 2500/3500 2019 2021 L5P
Silverado 4500HD/
5500HD/6500HD 2019 2021 L5D
Silverado LD 2019 2019 LM2
Tahoe 2021 2022 LM2
GMC
Canyon 2016 2021 LWN
Savana 2017 2021 LWN
Sierra 2017 2018 L5P
Sierra 1500 2020 2021 LM2
Sierra 2500/3500 2019 2021 L5P
Sierra Limited 2019 2019 LM2
Terrain 2018 2019 LH7
Yukon Models 2021 2022 LM2
Involved Region or Country
North America, Middle East, Israel, Palestine, Argentina, Brazil, Chile, Colombia,
Ecuador, Paraguay, Peru, Uruguay, China, Thailand, Egypt, Other Africa, Australia/New
Zealand
Condition
Some technicians may comment that after replacing the DEF pump, the pump will not
build pressure and one or more of the following DTCs may set:
• P20E8: Reductant Low Pressure
• P249C: Excessive Time To Enter Closed Loop Reductant Injection Control
Page 2 August, 2021 Bulletin No.: 20-NA-110
Information
If after replacing the DEF pump, the system is unable to build pressure, inspect for any
leaks, loose connections or kinks in the supply line.
After performing an initial leak test three times, if low pressure is present, this may be
because the DEF pump filter has dried out.
Allow the vehicle to sit overnight with the new pump and DEF fluid to re-saturate the DEF
pump filter. In the morning, perform the leak test three additional times. The pump should
now be able to build pressure.
Parts Information
No parts are required for this repair.
Warranty Information
Important: This Labor Operation should not be used
for initial diagnosing of low system pressure. This Labor
Operation should only be used if after the emission
reductant fluid tank (4025130 Emission Reduction Fluid
Tank Replacement) or the emission reductant fluid
pump (4029820 Emission Reduction Fluid Supply
Pump Module Replacement) has been replaced and
the system will not build pressure.
Important: Only apply the additional labor time if the
vehicle requires overnight soak time and re-test.
For vehicles repaired under the Emission coverage
(Coverage Code E), use the following labor operation.
Reference the Applicable Warranties section of
Investigate Vehicle History (IVH) for coverage
information.
Labor
Operation
Description Labor Time
4087458* Perform DEF Pump
Pressure Test
0.4 hr
*This is a unique Labor Operation for bulletin use only.
Version 4
Modified
Released June 11, 2020
October 13, 2020 – Added the Attention statement, 2016 Model Year to Colorado and
Canyon, updated the Involved Region or Country section, added first Important statement
under Warranty Information and updated the warranty coverage statement.
January 11, 2021 – Added the 2021 Model Year and removed Korea.
August 20, 2021 – Added the 2021-2022 Cadillac Escalade, Chevrolet Tahoe and GMC
Yukon models and Australia/New Zealand to the Involved Region or Country section.

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