22-NA-056

Bulletin No.:
Service Bulletin
Date:
22-NA-056
March, 2022
TECHNICAL
Subject:
Brand:
Buick
Malfunction Indicator Lamp (MIL) Illuminated - DTC P0172, P06DE and/or P0521 Set
Model:
Model Year:
from
Envision
from
to
—
—
Engine:
Transmission:
2.0L Turbo
(RPO LTG)
—
2020
Regal
Camaro
VIN:
to
2020
2022
Chevrolet
Equinox
2020
Malibu
2022
GMC
Terrain
2021
Involved Region or Country
North America, Middle East, Israel, Palestine, Argentina, Brazil, Chile, Colombia,
Ecuador, Paraguay, Peru, Uruguay, Japan, GM Korea Company, Thailand, Egypt, Other
Africa
Condition
Some customers may comment that the MIL is illuminated.
Technicians may find DTC P0172 (Fuel Trim System Rich) set in the engine control
module (ECM).
Technicians may also find DTC P06DE and/or P0521 set.
Cause
This condition may be caused by driving the vehicle in short intervals, allowing excessive
fuel to collect in the crankcase.
Correction
Important: This service procedure is for vehicles that have fuel enriched engine oil due
to frequent short trip operation. Replacing fuel components such as the high pressure fuel
pump or fuel injectors will not correct the setting of P0172 under the operating conditions
described unless those components can be verified as causing a fuel rich condition.
P06DE and/or P0521 may or may not be set due to a fuel enriched engine oil condition.
If fuel in the engine oil has been confirmed to be caused by frequent short trip operation,
perform an oil change.
Service Procedure
If P0172 is caused by excessive fuel in the crankcase,
the long term fuel trim should be a large negative
number.
– Confirm the long term fuel trim is a large negative
number (-18% to -30%)
If the MAF sensor is unplugged and the long term fuel
trim does not move into a normal range of (-10% to
+10%), then check crankcase oil level for being
overfilled and having an excessive fuel odor.
Note: An oil and filter change is necessary to remove
excessive fuel collected in the crankcase and correct
the DTC set.
1. Perform an oil change. Refer to Engine Oil and Oil
Filter Replacement in the Service Manual.
2. Clear the code and take the vehicle for a test drive
to validate that the code does not return.
Copyright 2022 General Motors LLC. All Rights Reserved.
Important: If the customer continues to frequently
operate the vehicle in this manner, they MUST change
the engine oil and filter more frequently than the oil life
monitor indicates. How often the customer must
change the engine oil is based on how they operate the
vehicle.
Parts Information
Causal
Part
Description
Part
Number
Qty
N/A
FILTER, OIL
1
N/A
OIL
Refer to the
Electronic
Parts
Catalog
(EPC).
As Required
Page 2
March, 2022
Bulletin No.: 22-NA-056
Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Note: Warranty Coverage Code E applies to Labor
Operation 4088368.
Labor
Operation
Description
Labor Time
4088368*
Oil and Filter Change for
DTC P0172 Set
0.3 hr
Add
Diagnose MIL and
Clear Code
0.2 hr
*This is a unique Labor Operation for bulletin use only.
Version
1
Modified
Released March 11, 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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