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Service bulletin TSB 21-2174

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 id10198584
Published by NHTSA2021-07-01
Manufacturer's numberTSB 21-2174
Manufacturer's date2021-06-02
NHTSA componentPOWER TRAIN

NHTSA's summary

Some 2021 Mustang vehicles equipped with a 5.0L engine and built on or before 11-Feb-2021 may exhibit an intermittent rough running drivability concern with an illuminated malfunction indicator lamp (MIL) and diagnostic trouble codes (DTC) P0351, P0352, P0353 and/or P0354 stored in the powertrain control module (PCM). This may be due to a software parameter within the PCM. To correct the condition, follow the Service Procedure to reprogram the PCM.

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

Transmission and driveline

Trouble codes named

P0351, P0352, P0353, P0354

Vehicles listed
FORD MUSTANG2021

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
TSB 26-22262026-05-14. Service bulletin. This bulletin supersedes 26-2046. Reason For Update: update the parts list to change the claim quantity of the C clutch friction plates (HL3Z-7B164-A), C clutch steel plates (HL3Z-7B442-F), D clutch steel plates (HL3Z-7B442-D), add the rear driveshaft flange CV joint-to-pinion flange cup bolts and retaining straps (LK4Z-4B496-B) for Transit, and update the parts description for the transfer case fluids applicable for each vehicle line. Some of the vehicles listed in the Model statement above may exhibit all of the following conditions: * Harsh engagement * Delayed engagement * Harsh shift * Delayed shift * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module (PCM) or transmission control module (TCM). This may be due to PCM software and/or axial movement of the CDF clutch cylinder (7H351) sleeve causing hydraulic circuit
SSM 547192026-04-10. Service bulletin. For 20212026 vehicles equipped with the 10R80 transmission, a new Transmission Clutch Circuit Leak Test has been introduced in the Ford Diagnosis and Repair System (FDRS). This test utilizes the pressure and vacuum transducer (PVT) when available. When referred to a specific clutch (A-F) test by a pinpoint test in Workshop Manual (WSM), Section 307-01 > Diagnosis and Testing, the Clutch Assembly tests have been updated with a hyperlink to the new Transmission Line Pressure Test - Pressure Vacuum Transducer (PVT) Is Available procedure in WSM, Section 307-01 > General Procedures. This procedure provides instructions to perform the FDRS Transmission Clutch Circuit Leak Test when applicable. The new test improves the accuracy of detecting leaks within transmission fluid circuits and replaces the previous air check method. The previous air check procedure has been shown to produce a high rate of false positives, which may lead to unnecessary repairs when no actual leak is present. Accordingly, the air check procedure is not to be used for diagnosing internal transmission hydraulic leaks or as justification
SSM 546742026-04-06. Service bulletin. For 2021-2026 vehicles equipped with the 10R80 transmission, a new Transmission Clutch Circuit Leak Test has been introduced in the Ford Diagnosis and Repair System (FDRS). This test utilizes the pressure and vacuum transducer (PVT) when available. The Workshop Manual (WSM) has been updated under Section 307-01 > Diagnosis and Testing to include this procedure. The new test improves the accuracy of detecting leaks within transmission fluid circuits and replaces the previous air check method.
TSB 26-20462026-02-17. Service bulletin. This bulletin supersedes TSB 25-2611. Reason For Update: Change the part number for the transmission fluid heat exchanger bolt (Expedition/Navigator) as well as change the claim/package quantities for HL3Z-7B442-F and HL3Z-7B164-C. Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: * Harsh engagement * Delayed engagement * Harsh shift * Delayed shift * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module (PCM) or transmission control module (TCM). This may be due to PCM software and/or axial movement of the CDF clutch cylinder (7H351) sleeve causing hydraulic circuit leaks.
TSB 25-26112026-01-06. Service bulletin. This bulletin supersedes TSB 25-2474 for 3 Part List corrections. Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: * Harsh engagement * Delayed engagement * Harsh shift * Delayed shift * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module (PCM) or transmission control module (TCM). This may be due to PCM software and/or axial movement of the CDF clutch cylinder (7H351) sleeve causing hydraulic circuit leaks. NOTE: If internal transmission service is required to address a concern detected with the CDF clutch cylinder following this article, technicians should carefully inspect and replace other transmission components and flush transmission fluid cooler only as necessary to confirm proper function. Add a new line to the repair order to document any additional repairs
SSM 543662025-11-19. Service bulletin. Some 2015-2021 Ford and Lincoln vehicles may exhibit an illuminated MIL with diagnostic trouble codes (DTCs) P0011, P0012, P0014, P0015, P0016, P0017, P0018, P0019, P0021, P0022, P0024 and/or P0025. Pinpoint test HK in the Powertrain Control and Emissions Diagnosis (PC/ED) or in Section 303-14 of the Workshop Manual (WSM) has been updated to address this concern.
TSB 25-24742025-11-04. Service bulletin. This bulletin supersedes TSB 25-2429 for a labor operation correction. Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: * Harsh engagement * Delayed engagement * Harsh shift * Delayed shift * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module (PCM) or transmission control module (TCM). This may be due to PCM software and/or axial movement of the CDF clutch cylinder (7H351) sleeve causing hydraulic circuit leaks. NOTE: If internal transmission service is required to address a concern detected with the CDF clutch cylinder following this article, technicians should carefully inspect and replace other transmission components and flush transmission fluid cooler only as necessary to confirm proper function. Add a new line to the repair order to document any additional rep
TSB 25-24292025-09-18. Service bulletin. This bulletin supersedes TSB 25-2300 to update the production fix date. Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: * Harsh engagement * Delayed engagement * Harsh shift * Delayed shift * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module (PCM) or transmission control module (TCM). This may be due to PCM software and/or axial movement of the CDF clutch cylinder (7H351) sleeve causing hydraulic circuit leaks. NOTE: If internal transmission service is required to address a concern detected with the CDF clutch cylinder following this article, technicians should carefully inspect and replace other transmission components and flush transmission fluid cooler only as necessary to confirm proper function. Add a new line to the repair order to document any additional re
TSB 25-23002025-08-19. Service bulletin. This bulletin supersedes TSB 25-2131 to add reprogram for later level software, new Steps 1-4 in Service Procedure. Updated Part List with 3 superseded part numbers. Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: * Harsh engagement * Delayed engagement * Harsh shift * Delayed shift * Illuminated malfunction indicator lamp (MIL) with diagnostic trouble codes (DTC) P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module (PCM) or transmission control module (TCM). This may be due to PCM software and/or axial movement of the CDF clutch cylinder (7H351) sleeve causing hydraulic circuit leaks. NOTE: If internal transmission service is required to address a concern detected with the CDF clutch cylinder following this article, technicians should carefully inspect, replace other transmission components and flush transmission fluid cooler only as necessary
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