Home › Subaru › Ascent › 21V955000

Subaru Ascent, Legacy, Outback Transmission Software Can Break Chain

NHTSA campaign 21V955000 · Reported 2021-12-09 · Subaru of America, Inc.

high How serious is it? About this label

A broken chain means a sudden loss of drive power, which increases the risk of a crash, so get this done promptly even though the notice does not tell owners to stop driving.

What's wrong, in plain English

A programming mistake in the computer that runs the automatic transmission can let the transmission start pulling power before an internal drive chain is fully clamped. Over time that chain can slip and break. If it does, the vehicle loses drive to the wheels even though the engine is still running. Dealers will reload the software, check stored data and the chain guide for damage, and replace the transmission for free if damage is found.

What you should do

1. Check your VIN at nhtsa.gov/recalls for recall 21V955000 (Subaru's number WRK-21).
2. Schedule the reprogramming and inspection at a Subaru dealer, or call Subaru at 1-844-373-6614; the work is free.
3. If your vehicle was already repaired under the earlier recall 19V-855, you still need this newer repair — mention that when you book.

Affected vehicles (4)

2019 Subaru Ascent
2020 Subaru Ascent
2020 Subaru Legacy
2020 Subaru Outback

Who to contact

Subaru — official Subaru recall lookup

Customer service: 1-844-373-6614

Any franchised dealer for the brand can do the repair. Phone numbers are taken from manufacturer sites and recent NHTSA notices; if one has changed, the number in your own recall letter is the one to use.

The bigger picture

Subaru driveshaft and transmission recalls: why the car loses drive power · all 8 Subaru recalls in this area

Official notice

Component: POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM)
Summary: Subaru of America, Inc. (Subaru) is recalling certain 2019-2020 Ascent, 2020 Legacy and Outback vehicles. A programming error in the Transmission Control Unit (TCU) may allow the clutch to engage before the drive chain is completely clamped.
Safety risk: An improperly secured drive chain may slip and break, causing a loss of drive power and increasing the risk of a crash.
Remedy: Dealers will reprogram the TCU, inspect TCU data for chain slip, and visually inspect the chain guide. If evidence of chain slippage or damage is found, the transmission will be replaced. Repairs will be performed free of charge. Owner notification letters were mailed August 19, 2022. This recall includes all vehicles previously recalled under 19V-855. Vehicles previously recalled under 19V-855 will need to have the new remedy performed for this recall once available. Owners may contact Subaru customer service at 1-844-373-6614. Subaru's number for this recall is WRK-21.

Verify your specific vehicle by VIN at nhtsa.gov. Recall repairs are free of charge by law.