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Service bulletin 21-NA-155

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11013242
Published by NHTSA2025-01-30
Manufacturer's number21-NA-155
Manufacturer's date2025-01-17
NHTSA componentSERVICE BRAKES; ELECTRICAL SYSTEM

NHTSA's summary

This informational bulletin advises the technician to check for faults that may be caused by the trailer otherwise found by a possible faulty trailer connector.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Brakes, Electrical system

Vehicles listed
CADILLAC ESCALADE2021, 2022, 2023, 2024, 2025
CADILLAC ESCALADE ESV2021, 2022, 2023, 2024, 2025
CHEVROLET SILVERADO 15002019, 2020, 2021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 25002020, 2021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 35002020, 2021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SUBURBAN2021, 2022
CHEVROLET SUBURBAN2024
CHEVROLET SUBURBAN 15002021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET TAHOE2021, 2022, 2023, 2024, 2025
GMC SIERRA 15002019, 2020, 2021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA 25002020, 2021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA 35002020, 2021, 2022, 2023, 2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA DENALI2020 (the catalog's model; the bulletin names a series or trim of it)
GMC YUKON2021, 2022, 2023, 2024, 2025
GMC YUKON XL2021, 2022, 2023, 2024, 2025
GMC YUKON XL 15002023 (the catalog's model; the bulletin names a series or trim of it)

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
25V7680002025-11-06. SERVICE BRAKES, HYDRAULIC:POWER ASSIST
25V3900002025-06-12. SERVICE BRAKES, HYDRAULIC:BRAKE FLUID LOW WARNING:SWITCH/SENSOR/FLOAT
24V9370002024-12-18. FORWARD COLLISION AVOIDANCE: WARNINGS:EXTERNAL/PEDESTRIAN ALERT; ELECTRICAL SYSTEM:BODY CONTROL MODULE/BCM
24V6740002024-09-12. SERVICE BRAKES, HYDRAULIC:POWER ASSIST:ELECTRIC:CONTROL MODULE:SOFTWARE; SERVICE BRAKES, HYDRAULIC:BRAKE FLUID LOW WARNING: LAMP
24V3200002024-05-09. ELECTRICAL SYSTEM:PROPULSION SYSTEM; ELECTRICAL SYSTEM:WIRING
20216022021-09-29. Brakes
21V7580002021-09-29. SERVICE BRAKES, HYDRAULIC:POWER ASSIST:ELECTRIC:CONTROL MODULE
21V5790002021-07-29. SERVICE BRAKES, HYDRAULIC:POWER ASSIST:ELECTRIC:CONTROL MODULE:SOFTWARE
21V4210002021-06-10. AIR BAGS:SRS MALFUNCTION WARNING LAMP/LIGHT; ELECTRICAL SYSTEM:SOFTWARE
20V7900002020-12-17. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
N2525290802026-04-01. Service campaign. Service Update. Certain vehicles listed above may be missing a high voltage header plug on the RESS battery pack drive motor connector. Dealers are to inspect the RESS pack connectors and install the proper HV Header Plug if missing.
N2525155902026-01-27. Service campaign. Certain vehicles listed above, may have a condition in which the body-to-chassis ground strap may be corroded. Dealers will replace the ground strap.
25-NA-0212025-12-03. Service bulletin. This technical bulletin provides repair information to correct a customer concern of Radio Software Update W23E-178.1.2-M174-SQBR6-93.3.
25-NA-1212025-10-27. Service bulletin. This service bulletin provides information on the radio software related issues to update the radio to the latest software version Y177.
25-NA-1192025-10-27. Service bulletin. This service bulletin provides information on the Service Safety Restraint Message displayed on the DIC Airbag malfunction indicator illuminated.
25-NA-1082025-10-27. Service bulletin. This bulletin provides a procedure to inspect and verify the drive shafts are over extending past the 5mm tolerance, causing the customers concern of a fluid leak under the vehicle.
25-NA-0442025-10-27. Service bulletin. This service bulletin provides information for dealers/technicians on SPS2 Hybrid/EV Battery Data Retrieval for Service High Voltage DTCs.
24-NA-2022025-10-27. Service bulletin. This service bulletin provides dealers with Warranty Administration information on North American Charging Standard (NACS) DC Adapter Warranty Claim Information.
23-NA-2022025-10-25. Service bulletin. This service bulletin provides information on High Voltage Drive Motor Battery - TAC Approval and Exchange Program for BrightDrop, Chevrolet Silverado EV, and GMC Sierra EV, HUMMER EV/SUV.
23-NA-1702025-10-25. Service bulletin. This bulletin advises the tech to inspect deeper into what may be to main cause of an engine failure.