Service bulletin TSB 21-2155

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)
Type	Service bulletin
NHTSA id	10194436
Published by NHTSA	2021-06-03
Manufacturer's number	TSB 21-2155
Manufacturer's date	2021-05-18
NHTSA component	STRUCTURE:BODY:HOOD; EQUIPMENT

NHTSA's summary

Some 2020-2021 Mustang Shelby GT500 vehicles may exhibit a cracking on the hood inner panel. The crack is a cosmetic condition, not a structural concern. This may be due to a variation in production of the hood. To correct the condition, follow the Service Procedure to repair the hood crack.

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

Body and frame, Equipment and accessories

Vehicles listed
FORD MUSTANG	2020, 2021

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

Other bulletins for the same vehicles and component
SSM 54601	2026-02-27. Service bulletin. Ford and Lincoln vehicles equipped with wired keyless entry keypad systems and accessory wireless keyless entry keypad systems may or may not come with a wallet card containing the master code. Unlike the integrated wired keypad, the accessory wireless keypad master code cannot be retrieved from the vehicle using a diagnostic scan tool or from the label printed on the body control module (BCM). The Factory Keyless Entry Code application within the diagnostic scan tool will not provide an applicable master code for the accessory wireless keypad. If the wallet card for an accessory keypad is not available, the "Wireless RF Keypad Diagnosis Guide" can be referenced and provides direction on how to retrieve the master code. This guide is located under the Workshop Manual tab > Accessories > Installation > Wireless RF Keypad Diagnosis Guide > PPT C > Step C2.<br /><br /> Note: The only available keypad for some vehicles from the assembly plant is the accessory wireless keyless entry keypad. The integrated wired keypad cannot be installed on vehicles not equipped from the factory with a wired keyless entry k
SSM 52476	2024-05-03. Service bulletin. All accessory stick-on keyless entry keypads come with a wallet card containing the master code. If the accessory keypad was factory installed, this card will be placed in the glove box and should be handed to the vehicles owner during initial delivery. Unlike the integrated (wired) factory keypad, the accessory keypad master code cannot be retrieved from the vehicle using a diagnostic scan tool. If the wallet card for an accessory keypad is lost, follow these steps to recover the code. Dealer Key Code access is granted through the Dealer Program Enrollment System (DPES); dealership management can authorize users. The authorized user must go to FMCDealer.com > Parts and Service > Parts Product Line Information > Keys/Entry Devices > Aftermarket Keyless Entry Keypad Code Access. Follow the instructions on the screen to obtain the master code for the accessory keypad.
TSB 23-2433	2024-01-05. Service bulletin. Some 2015-2020 Mustang vehicles built on or before 30-Aug-2020 may exhibit a rattle like noise coming from the front seat. This may be due to the mating surface between the seat frame and floor pans. To correct this condition, follow the Service Procedure to clean the mating surface.
21N10 S1	2023-12-05. Service bulletin. Certain 2015 – 2021 Model Year Mustang Convertible Vehicles - Door Opens to Secondary Latch Position
TSB 23-2334	2023-11-03. Service bulletin. This article supersedes TSB 21-2220 to update the model years affected and part list. Some 2018-2024 Mustang coupe vehicles may exhibit a sagging headliner or gap where the headliner meets the upper door weatherstrip. This may be due to an outward bent door frame moulding not allowing the weatherstrip to overlap the headliner properly. To correct this condition, follow the Service Procedure to replace the door frame moulding.
TSB 23-2307	2023-11-02. Service bulletin. Some 2019-2020 Edge/F-150/Fusion/Continental/MKZ/Nautilus, 2019-2021 Mustang/Ranger/Transit Connect, 2020-2021 EcoSport/Escape/Expedition/Explorer/F-Super Duty/Aviator/Corsair/Navigator, 2021 Bronco Sport and 2020-2022 Explorer/Aviator vehicles with SYNC 3 may experience various SYNC performance related concerns. This may be due to the SYNC Software. To correct the condition, follow the Service Procedure to update the SYNC module (APIM) software.
SSM 51947	2023-10-06. Service bulletin. Some 2015-2019 F-Super Duty and 2015-2020 F-150/Mustang vehicles may require replacement of the powertrain control module (PCM) for various reasons. While performing a programmable module installation (PMI) using the Integrated Diagnostic Service (IDS) scan tool, an error message may state: Configuration Failed, Would You Like To Retry? This may be due to improper module replacement steps. Make sure that the original module is installed in the vehicle, delete the vehicle session, then start a new vehicle session. Once the session starts, run the PCM PMI and install the new PCM only when the scan tool instructs. Finish the PMI by following the prompts given by IDS. If the original PCM is not available, it is possible to configure the module by running as-built programming on the PCM. When IDS asks to obtain part numbers or configuration data, select configuration data.
SAN-Vol1 I1	2023-08-16. Service bulletin. The Service Awareness Newsletter is an informal communication that contains information that may not be presently available in a TSB, SSM, GSB, or other electronic communication. This article includes information on warranty, technical service tips and other service information.
SB23-01	2023-08-03. Service bulletin. Spl Parts, Inc. communications index accompanying MCP uploads 23mc40464 & 23mc40471
SB 23-01	2023-08-02. Service bulletin. SPL Parts, Inc. manufacturers and distributes aftermarket lower control arms for dedicated competition vehicles and "track day" cars some of which may be used on both track and highway. SB 23-01 adresses proper installation torque of cap bolt fasteners attaching SPL's aftermarket lower control arms, recurring inspection and confirmation of torque setting and removal and replacement of damaged or under torqued fasteners to reduce risk of premature failure and accident. SB-23-01 was mailed, emailed and posted on SPL website to known resellers, race teams and users of the affected parts and is being submitted here as required by part 579.5. Vehicle Applications include: BMW series 1,2,3,& 4, 2008-2023; Chevrolet Camaro 26-2023, Cadillac ATS, CTS 2016-2019; Ford Mustang 2015-2023; Toyota Supra 2020-2023.