16NA377

File in Section:
Bulletin No.:
Service Bulletin
Date:
16-NA-377
September, 2017
INFORMATION
Subject:
Service Emission System Message with DTC P206B Set/Stored
Brand:
Model:
Colorado
Chevrolet
GMC
Model Year:
VIN:
Engine:
Transmission:
2018
LWN
All
from
to
2017
from
to
Cruze
2017
2018
Gen II , LH7
All
Equinox
2018
2018
LH7
All
Express
2017
2018
LWN
All
Silverado
2017
2018
L5P
All
Canyon
2017
2018
LWN
All
Terrain
2018
2018
LH7
All
Savana
2017
2018
LWN
All
Sierra
2017
2018
L5P
All
Involved Region or Country
North America and Israel
Additional Options (RPO)
Equipped with Diesel Engine (RPO L5P, LH7, or LWN)
Condition
Some customers may comment on a Service Emission System Message. This usually
occurs after recently filling the DEF tank with the ignition in the on position, if:
• Using a mobile fill cart with an automatic nozzle
• Filling up at a commercial truck service station with DEF dispensing equipment
During diagnosis a technician may find DTC P206B set or stored in the history.
Note: Shortly after filling, the “Service Emission System” will clear on its own.
Cause
It has been found that some DEF fill equipment uses pumps that create a high level of
temporary aeration of the DEF fluid being dispensed in the tank. This aeration of the DEF
fluid could cause a temporary issue affecting the proper operation of the in-tank DEF
Quality sensor. Seconds after a fill event completes the aeration dissipates and the DEF
Quality sensor will return to its normal operation however if the customer has the vehicle
keyed on during the fill event it is likely that this condition could occur.
Information
To reduce the likelihood of this issue occurring, the
vehicle should be keyed off during filling of the DEF
tank. In the event the condition is seen, the vehicle
should remain keyed on until the “Service Emission
System” warning clears. The P206B code in history can
Copyright 2017 General Motors LLC. All Rights Reserved.
then be cleared. While not required some DEF filling
equipment can be sold with an air/fluid separator, which
can further reduce the likelihood of fluid aeration.
Page 2
September, 2017
Bulletin No.: 16-NA-377
Version
3
Modified
Dec. 20, 2016 – Added Chevrolet Express, Colorado, Cruze and GMC Canyon, Savana
models with additional RPOs LWN and LH7. The Note in the Condition has been
updated.
September 05, 2017 — Updated Model Years.
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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