20NA110

Bulletin No.:
Service Bulletin
Date:
20-NA-110
January, 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:
Chevrolet
GMC
Model:
Model Year:
VIN:
from
to
Engine:
from
to
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
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
Transmission:
Involved Region or Country
North America, Middle East, Israel, Palestine, Argentina, Brazil, Chile, Colombia,
Ecuador, Paraguay, Peru, Uruguay, China, Thailand, Egypt, Other Africa
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
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.
Copyright 2021 General Motors LLC. All Rights Reserved.
Page 2
January, 2021
Bulletin No.: 20-NA-110
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
4087458*
Description
Labor Time
Perform DEF Pump
Pressure Test
0.4 hr
*This is a unique Labor Operation for bulletin use only.
Version
3
Modified
Released June 11, 2020
Revised 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.
Revised January 11, 2021- Added 2021 Model Years and Removed Korea.
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.
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