22-NA-203

Bulletin No.:
Service Bulletin
Date:
22-NA-203
October, 2022
TECHNICAL
Subject:
Check Engine Lamp Illuminated on Driver Information Center (DIC) with DTC P0451 Set
Model Year:
Brand:
Model:
Buick
Envision
2021
Cadillac
XT4
2019
from
to
2023
VIN:
from
to
Engine:
Transmission:
LAH, LSY
or LXH
Involved Region or Country
United States, Canada, Mexico, Europe, Russia, Middle East, Israel, Palestine, Japan,
Cadillac Korea (South Korea)
Condition
Some customers may comment on a malfunction indicator lamp illuminated. During
diagnosis some technicians may find DTC P0451 (Fuel Tank Pressure Sensor
Performance) set in the ECM.
Cause
Liquid fuel can enter vapor lines following a customer fuel overfill. If a customer goes
beyond three clicks at the fuel station fill, liquid fuel could enter the vapor line through the
recirculation line. The liquid fuel can block the line and cause issues with the fuel tank
pressor sensor readings.
Correction
Technicians should inspect the vent lines at the fuel tank for any exterior damage and
drain any liquid fuel and/or contamination from the evap vent lines and then clear
the DTC.
It will also be necessary to educate the three-click fuel fill procedure with the customer.
Service Procedure
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
1. Raise the vehicle.
2. Disconnect the 3 vapor lines near the gas tank.
6175877
3. Drain any liquid fuel from each of the 3 vapor lines.
4. Lower the vehicle and remove the RH rear wheel
and RH rear wheel liner. Refer to the proper
replacement procedure within Si.
Copyright 2022 General Motors LLC. All Rights Reserved.
Page 2
October, 2022
Bulletin No.: 22-NA-203
6175879
5. Disconnect the vapor lines from the evap canister.
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6. Lightly blow shop air into the two vapor lines
shown below (w/ green quick connectors) to clear
the lines of any liquid fuel.
7. Reconnect all of the vapor lines at the canister.
8. Reinstall the RH wheel liner and the RH rear
wheel.
9. Reconnect the vapor lines under the vehicle.
10. Lower the vehicle.
11. Clear DTC’s
Note: Educate the customer about attempting to
overfill the system during the fueling process and not to
exceed three-clicks at the fuel pump.
Parts Information
No parts are required for this repair.
Warranty Information
6175880
For vehicles repaired under the Bumper-to-Bumper
coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH)
for coverage information.
Labor Operation
Description
Labor Time
4088788*
Clear Restriction From Evap System Vent Lines
0.6 hr
*This is a unique Labor Operation for Bulletin use only.
Version
1
Modified
Released October 17, 2022
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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