18NA380

File in Section:
Bulletin No.:
Service Bulletin
Date:
18-NA-380
December, 2018
TECHNICAL
Subject:
Malfunction Indicator Light (MIL) Illuminated - DTC P20EE Set
Brand:
Chevrolet
Model Year:
Model:
4500HD/
4500XD
Medium
Duty (LCF)
5500HD/
5500XD
Medium
Duty (LCF)
VIN:
from
to
2018
2019
from
Engine:
Transmission:
to
I1B
Involved Region or Country
North America
Condition
Some customers may comment that the MIL is illuminated.
Some technicians may find DTC P20EE (Diesel Exhaust Fluid (DEF) System NOx Trap
Low Efficiency) set in the DEF Control Module.
New calibrations for the DEF Control Unit (DCU) have been developed to address this
concern.
Refer to SI for diagnostic for DTC P20EE.
Correction
⇒ If no fault can be found when performing the normal diagnosis, follow the
service procedure in this bulletin to reprogram the DEF Control Module.
Service Procedure
Important: Stable battery voltage is critical during
programming. Any fluctuation, spiking, over voltage or
loss of voltage will interrupt programming. 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.
If the calibration number of the module is listed below
the calibration number shown in table, reprogram the
DCU with the latest software and calibration.
If the calibration number of the module is listed above
the calibration number shown in table, follow the
Intermittent Conditions diagnostics in the appropriate
Service Manual.
Model Year
Vehicle
Engine
Transmission
Calibration #
2018
4500/5500 HD/XD
5.2L
Auto
97536100
2019
4500/5500 HD/XD
5.2L
Auto
97536101
Copyright 2018 General Motors LLC. All Rights Reserved.
Page 2
December, 2018
Bulletin No.: 18-NA-380
Labor Operation
Description
Labor Time
L4012
DTC P20EE DCU Recalibration
0.4 hr
Parts Information
No parts are required for this repair.
Warranty Information
For vehicles repaired under warranty, use:
Version
1
Modified
Released December 20, 2018
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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