NHTSA ID Number: 11013082
Manufacturer Communication Number: 24-NA-173
TSB/Document Date: 2025-01-24
Summary
This bulletin advises the technician that if the code sets, verify the sensor then inspect the engine oil pump for a sticking valve that may cause the MIL to illuminate.
Bulletin No.: 24-NA-173
Service Bulletin
Date: January, 2025
TECHNICAL
Subject:
Brand:
Malfunction Indicator Lamp (MIL) Illuminated - DTC P0521 Set
Model:
from
to
Escalade Models
2021
2024
Silverado 1500
(New Model)
2019
2019
Silverado 1500
2020
2021
Silverado 1500
Limited (RPO J21,
12th VIN Digit = 4
or less
2022
2022
Build Date:
from
Engine:
to
Transmissi
on:
L87
Silverado 1500 New
(RPO J22, 12th VIN
Digit = 5 or greater)
Silverado 1500
Suburban
Tahoe
Model Year:
2023
2019
2024
L84, L87
Sierra 1500 (New
Model)
2019
2019
Sierra 1500
2020
2021
2022
2022
Sierra 1500 Limited
(RPO J21, 12th VIN
Digit = 4 or less)
Sierra 1500 New
(RPO J22, 12th VIN
Digit = 5 or greater)
Sierra 1500
2023
Yukon Models
2019
2024
Involved Region or Country
North America
Condition
Some customers may comment that the MIL lamp is illuminated or was Illuminated and
turned off.
Some technicians may find DTC P0521 (Engine Oil Pressure Sensor Performance) set
active or stored in history.
- During inspection, Technician may notice after reviewing vehicle history, the engine oil
pressure sensor or ECM was replaced on a prior visit for the same concern.
Cause
This condition may be caused by a stuck oil pressure relief valve inside the oil pump
assembly.
- This stuck pressure relief valve could cause low oil pressure at idle thus setting the
DTC noted above
Correction
Before inspecting the oil pump, please follow the diagnostic flow chart for P0521 to
ensure there are no electrical or oil pressure sensor concerns.
Copyright 2025 General Motors. All Rights Reserved.
Page 2
January, 2025
⇒
Bulletin No.: 24-NA-173
If no electrical or oil pressure sensor concerns were found, proceed to next step.
Important: This test must be done at idle and when oil is hot.
If you find P0521 is current or set in history, it will be necessary to first perform a
mechanical oil pressure test using the oil pressure test adapter kit noted in service
information under Oil Pressure Diagnosis and Testing.
Important: Oil pressure can vary greatly when checking oil pressure at the oil filter
location using the adapter specified in the service procedure vs checking oil pressure at the
oil pressure sensor location. It was noted a difference up to 10 psi was found when
checking at both locations.
If oil pressure reading is anything below 20 psi when measured at the oil sensor port,
then this issue may be related to a stuck oil pressure relief valve inside the oil pump
assembly.
It will then be necessary to remove oil pump for further inspection.
• (1) Stuck Valve
6724292
• (2) Normal Valve
If the Valve has been found stuck, replace the oil pump.
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.
Service Procedure
Refer to Oil Pump Replacement.
Parts Information
Note: Only select the parts that coincide with the repair performed. Replace the part with the P/N outlined in the
Electronic Parts Catalog (EPC) in accordance with the vehicle VIN.
Note: Follow the procedure in SI for additional parts that may be required for the repair.
Bulletin No.: 24-NA-173
January, 2025
Causal
Part
Description
Part
Number
Qty
X
PUMP, OIL (RPO
L84)
12733671
1
X
PUMP, OIL (RPO
L87)
12733670
1
Page 3
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.
Labor
Operation
Vehicle
Description
Labor Time
4088498*
All
Diagnosis
Time for DTC
P0521 Set
0.5
Oil Pump
Replacement
2WD
5.6
Add
Oil Pump
Replacement
4WD
8.6
Add
Oil Pump
Replacement
L84 with 2WD
5.5
Oil Pump
Replacement
L84, L87 with
4WD
9.3
Add
Escalade
Sierra/
Silverado
Add
Add
Add
Add
Add
Oil Pump
Replacement
Yukon/
2WD
Suburban/
Tahoe (2019–
Oil Pump
2020)
Replacement
4WD
Oil Pump
Replacement
Yukon/
2WD
Suburban/
Tahoe (2021–
Oil Pump
2024)
Replacement
4WD
6.4
7.2
5.6
8.6
Add
RC1 (PLATEFULL BODY,
SKID)
If Equipped
0.2
Add
WTX
(FASCIAFRT,
STANDARD)
If Equipped
0.2
Add
F47
(SUSPENSIO
N SYSTEMFRT & RR,
AIR)
If Equipped
0.3
Add
To Recover
and Recharge
R-1234yf A/C
System
If Equipped
1.2
Page 4
Labor
Operation
Add
January, 2025
Vehicle
Description
Labor Time
To Recover
and Recharge
R-134a A/C
System
If Equipped
0.3
Bulletin No.: 24-NA-173
*This is a unique Labor Operation for Bulletin use only.
Version
2
Modified
Released September 12, 2024
Revised January 09, 2025 - Update Labor Op Times for Yukon/Suburban/Tahoe in the
Warranty Information section.
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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TSB/Document ID: 24-NA-173
Replacement Service Bulletin Number:
MFR Communication Date: 2025-01-10
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ENGINE
MFR Component System:
MFR Component Subsystem:
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