This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers).
full bulletin at NHTSA ↗2021 Subaru Legacy engine problems
moderate 3 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Complaints
3
Recalls
0
Avg fix
$3,100
When does it fail?
Of the 3 engine complaints filed for the 2021 Subaru Legacy, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin announces the diagnostic procedures to be used when DTCs B1571(REFERENCE CODE INCOMPATIBILITY IMMOBILIZER CM TO ECM) and B1572(IMM CIRCUIT EXCEPT ANTENNA CIRCUIT) are detected by Keyless Access with Push Button Start(KACM).
full bulletin at NHTSA ↗This Bulletin provides the diagnostic procedure for the STARLINK® Remote Engine Start (RES).
full bulletin at NHTSA ↗This bulletin announces the design change made to the high-pressure fuel pump developed to prevent DTC P0087 (Fuel Rail/System Pressure – Too Low Bank 1).
full bulletin at NHTSA ↗This Service Information Bulletin outlines a new required procedure to follow when performing immobilizer-related repairs on models listed.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 2 most recent
The contact owns a 2021 Subaru Legacy. The contact stated that while driving at various speeds during colder weather, the heater failed to operate as intended. Additionally, the Eyesight system was inoperable. The check engine and other unknown warning lights were displayed. In addition, the contact stated that the engine failed to warm up as intended after being started, and the engine…
Subaru has released a service bulletin regarding concerns with the Thermo Control Valve in specific vehicles. Unfortunately, individuals with vehicles bearing a rebuilt title, including myself, are required to cover expenses exceeding $2,000 out of their own pockets. Despite evidence indicating that the issue with the engine area is unrelated to the vehicle's rebuilt title, Subaru has chosen not…
Had engine trouble with your 2021 Subaru Legacy?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2021 Subaru Legacy?
It's a documented issue but not catastrophic. 3 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Based on the 3 complaints filed, engine issues most often appear around 60,000 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Subaru/Legacy.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.