Ford Mustang 2020 — technical service bulletin
Bulletin 21B26-S1 · NHTSA communication 10198613 · issued Jun 8, 2021
Technical service bulletin
communication type
Engine and Engine Cooling
component
2020
model years
1
vehicle entries
Official summary
In some of the affected vehicles, the engine's secondary timing chain tensioner may not have been properly activated during assembly, which could result in a timing loss. Timing loss could lead to internal engine damage, a rough running engine , and engine misfires.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.