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Subaru · Known Issues

2024 Subaru Legacy Problems: 5 Known Issues

2024 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated September 2026

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Issue summary

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2024 Subaru Legacy has 5 documented known issues, with 1 rated critical. The most serious is Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating ($1,200-$2,200 repair). Across all issues with published estimates, repair costs range from $250 to $2,200. DIY maintenance guides at au7o.io.

In This Article

  • Legacy Cooling1
  • Legacy Electrical2
  • Legacy Brakes1
  • Legacy Exterior1
  • Recalls4
  • FAQ
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In This Article

  • Cooling1
  • Electrical2
  • Brakes1
  • Exterior1
  • Recalls4
  • FAQ

All 5 Known Issues

Filter:
ALL YEARS20242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999199819971996199519941993199219911990

When Issues Typically Appear

Battery Drain and No-Start from DCM/Telematics Module Staying Awake
0K-40K
Windshield Cracking Easily and Eyesight Camera Recalibration After Glass Replacement
0K-60K
Infotainment Head Unit Freezing, Black Screen, and CarPlay/Android Auto Connectivity Problems
0K-50K
Low-Speed Brake Pedal Pulsation or Vibration from Front Brake Rotor Deposits/Warping
5K-40K
Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating
10K-70K
025K50K75K100K mi

On the 2021-2024 Subaru Legacy 2.5L FB25, multiple owners of 7th-generation Legacy models have reported failure of the electronically controlled thermo control valve used in the FB25 cooling system. When the valve sticks or its internal position sensor fails, the car may illuminate the check engine light, lose cabin heat, run the radiator fans excessively, and in some cases overheat or enter a reduced-power mode. Subaru issued service information and the problem is widely documented across Subaru owner communities and complaint databases for this platform.

This issue also affects: Subaru Forester, Subaru Outback

Common Symptoms

  • check engine light
  • poor or no cabin heat
  • engine temperature fluctuates
  • radiator fans running constantly
  • overheating warning
  • reduced power mode

How to Fix

Diagnosis typically starts with scanning for cooling-system related DTCs and confirming abnormal coolant temperature behavior or heater output. The standard repair is replacement of the thermo control valve assembly, followed by coolant refill/bleed and verification of proper warm-up and fan operation. If overheating occurred, the cooling system should also be checked for secondary damage and trapped air.

Owner tips & cautions

  • TipIf the CEL appears with weak heat, scan immediately and avoid extended driving until coolant temperature behavior is confirmed normal.
  • TipAfter replacement, make sure the shop properly bleeds the Subaru cooling system to prevent repeat overheating complaints.
Typical repair cost:$1,200 - $2,200

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence

On the 2021-2024 Subaru Legacy, a well-documented issue on late-model Subaru vehicles including the Legacy involves parasitic battery drain tied to the Data Communication Module (DCM), telematics hardware, or related control modules not going to sleep properly. Owners report dead batteries after the vehicle sits overnight or for a few days, repeated jump-starts, and battery replacements that do not permanently solve the problem. This issue is reflected in Subaru service communications, owner forum threads, and NHTSA complaints.

This issue also affects: Subaru Solterra, Subaru WRX

Common Symptoms

  • dead battery after sitting
  • slow cranking
  • no-start condition
  • repeated need for jump-starts
  • battery replacement does not fix issue
  • intermittent warning lights after low voltage

How to Fix

Diagnosis requires a proper parasitic draw test after all modules should be asleep, with attention to the DCM/telematics circuit and battery condition. Repairs may include DCM replacement, software updates, battery replacement if damaged by repeated deep discharge, and verification that quiescent current drops to specification. Some vehicles also need charging-system and ground checks to rule out secondary causes.

Owner tips & cautions

  • TipAsk the dealer to document parasitic draw in milliamps after sleep mode rather than only load-testing the battery.
  • TipIf the battery has been deeply discharged multiple times, replacement is often needed even after the root-cause module is repaired.
Typical repair cost:$250 - $1,200

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence

On the 2021-2024 Subaru Legacy, the large center touchscreen used in the current Legacy has generated many owner complaints for lagging, freezing, random reboots, black screens, and unstable Apple CarPlay/Android Auto connections. In some cases climate and vehicle settings become difficult to access because many functions are integrated into the display. Subaru has released software updates and service information addressing infotainment bugs on this platform.

Common Symptoms

  • screen freezes
  • black or blank display
  • system reboots while driving
  • CarPlay disconnects
  • Android Auto disconnects
  • slow touchscreen response
  • backup camera image delayed or unavailable

How to Fix

First verify the head unit software version and apply the latest Subaru update if available. If problems persist, technicians typically inspect USB ports/cables, perform a factory reset, and in recurring cases replace the head unit or related hardware. Intermittent failures should be documented with photos or video because some units fail sporadically.

Owner tips & cautions

  • TipUse a high-quality short USB cable when troubleshooting CarPlay/Android Auto disconnects before condemning the head unit.
  • TipAsk the dealer to print the installed software version and compare it with the latest TSB revision before replacing hardware.
Typical repair cost:$0 - $1,800

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence

On the 2021-2024 Subaru Legacy, owners of current-generation Legacy models have reported brake pulsation, steering wheel shake, or vibration during moderate braking, sometimes at relatively low mileage. The condition is commonly attributed to front rotor thickness variation or uneven pad deposits rather than a hydraulic failure, but it can reduce braking smoothness and owner confidence. Reports appear in owner forums and complaint databases for this generation.

Common Symptoms

  • brake pedal pulsation
  • steering wheel shake while braking
  • vibration at highway speeds during braking
  • front-end shimmy on deceleration

How to Fix

Road-test the vehicle to confirm pulsation, then measure rotor runout and thickness variation. Repair usually involves resurfacing or replacing front rotors and pads, cleaning hub mating surfaces, and properly torquing wheel fasteners to prevent recurrence. If the vehicle is driven gently or sits often, a bedding procedure after repair can help reduce uneven deposits.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Genuine Subaru 26296AN04A Updated Front Brake Pad Kit

    updated front pad set after the front pads are confirmed as the pulsation/vibration source Fitment/availability: 2021-2024 Legacy 2.5-liter and 2.4-liter turbo front brakes within this card; Subaru bulletin 06-91-24R specifically covers …

    SubaruPartsDeal
  • Genuine Subaru 26300AN00A Front Brake Rotor

    front rotor pair only when measurement or condition rules out acceptable resurfacing Fitment/availability: 2021-2024 Legacy front rotor branch confirmed in the year/engine catalogs; quantity two when replacement is required, confirm VIN …

    SubaruPartsDeal

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Owner tips & cautions

  • TipHave wheel lug torque checked with a torque wrench, as uneven tightening can contribute to rotor runout complaints.
  • TipAfter rotor/pad replacement, perform a proper pad bedding procedure to minimize uneven transfer layer buildup.
Typical repair cost:$350 - $900

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
Medium Confidence

On the 2021-2024 Subaru Legacy, owners of 2021-2024 Legacy models frequently report windshields that crack from small stone impacts or develop long cracks quickly, often near the camera area. Because the windshield is integrated with the EyeSight driver-assistance system, replacement is more expensive than conventional glass and may require camera aiming/calibration. The issue is widely discussed in owner communities and appears in numerous NHTSA complaints for this generation.

Common Symptoms

  • crack spreads rapidly after small rock hit
  • stress crack near top or camera area
  • EyeSight disabled after windshield damage
  • high replacement cost
  • ADAS warning lights after glass replacement

How to Fix

Inspect the crack origin and determine whether repair is possible before it spreads; many cracks near the camera zone require full windshield replacement. Use OEM-quality glass when possible and ensure EyeSight static/dynamic calibration is completed after installation. If repeated breakage occurs, owners often document impact points carefully for warranty or insurance claims.

Owner tips & cautions

  • TipUse a glass shop experienced with Subaru EyeSight; improper calibration can leave warning lights on or disable driver-assistance features.
  • TipMany owners add full glass coverage through insurance because replacement cost is much higher than older non-ADAS windshields.
Typical repair cost:$900 - $1,800

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence
NHTSA Recalls4 recalls

POWER TRAIN:DRIVELINE:DRIVESHAFT

Subaru of America, Inc. (Subaru) is recalling certain 2023 Outback, Legacy, Ascent, and Impreza vehicles. The center support bolts for the driveshaft may loosen, resulting in the disconnection of the front end of the driveshaft.

Campaign #23V64700021/09/2023

POWER TRAIN:AUTOMATIC TRANSMISSION:PARK/NEUTRAL START INTERLOCK SWITCH

Subaru of America, Inc. is recalling certain model year 2021 Crosstrek, 2022 Forester, 2021-2023 Legacy, and Outback vehicles. An insufficient weld may allow water to enter the inhibitor switch, causing it to fail.

Campaign #23V75500009/11/2023

AIR BAGS:SENSOR:OCCUPANT CLASSIFICATION:FRONT PASSENGER

Subaru of America, Inc. (Subaru) is recalling certain 2020-2022 Outback and Legacy vehicles. A capacitor in the sensors for the Occupant Detection System (ODS) may crack and short circuit, which can prevent the front passenger air bag from deploying in a crash.

Campaign #24V22700022/03/2024
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Other Subaru Models

Subaru Forester46Subaru Outback40Subaru WRX31Subaru Ascent25Subaru Solterra24Subaru Crosstrek23

Frequently Asked Questions

What are the most common Subaru Legacy problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2024 Subaru Legacy has 5 documented issues. The most frequently reported are: Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating, Battery Drain and No-Start from DCM/Telematics Module Staying Awake, Low-Speed Brake Pedal Pulsation or Vibration from Front Brake Rotor Deposits/Warping. Of these, 1 is rated critical and should be addressed promptly.

Is the Subaru Legacy reliable?

The 2024 Subaru Legacy has 5 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 1 issue is rated critical: Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Subaru Legacy problems?

Repair costs for known Subaru Legacy issues range from $0 to $2,200, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating, typically costs $1,200-$2,200 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2021-2024 Subaru Legacy Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating?

Multiple owners of 7th-generation Legacy models have reported failure of the electronically controlled thermo control valve used in the FB25 cooling system. When the valve sticks or its internal position sensor fails, the car may illuminate the check engine light, lose cabin heat… Repairs typically run $1,200-$2,200. Severity: high.

What is the 2021-2024 Subaru Legacy Battery Drain and No-Start from DCM/Telematics Module Staying Awake?

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.

POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM)

Subaru of America, Inc. (Subaru) is recalling certain 2020-2021 Outback and Legacy vehicles. A programming error in the Transmission Control Unit (TCU) may allow the clutch to engage before the drive chain is completely clamped.

Campaign #22V48500008/07/2022

Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.

A well-documented issue on late-model Subaru vehicles including the Legacy involves parasitic battery drain tied to the Data Communication Module (DCM), telematics hardware, or related control modules not going to sleep properly. Owners report dead batteries after the vehicle sit… Repairs typically run $250-$1,200. Severity: medium.

What is the 2021-2024 Subaru Legacy Low-Speed Brake Pedal Pulsation or Vibration from Front Brake Rotor Deposits/Warping?

Owners of current-generation Legacy models have reported brake pulsation, steering wheel shake, or vibration during moderate braking, sometimes at relatively low mileage. The condition is commonly attributed to front rotor thickness variation or uneven pad deposits rather than a… Repairs typically run $350-$900. Severity: medium.

What is the 2021-2024 Subaru Legacy Windshield Cracking Easily and Eyesight Camera Recalibration After Glass Replacement?

Owners of 2021-2024 Legacy models frequently report windshields that crack from small stone impacts or develop long cracks quickly, often near the camera area. Because the windshield is integrated with the EyeSight driver-assistance system, replacement is more expensive than conv… Repairs typically run $900-$1,800. Severity: medium.

What is the 2021-2024 Subaru Legacy Infotainment Head Unit Freezing, Black Screen, and CarPlay/Android Auto Connectivity Problems?

The large center touchscreen used in the current Legacy has generated many owner complaints for lagging, freezing, random reboots, black screens, and unstable Apple CarPlay/Android Auto connections. In some cases climate and vehicle settings become difficult to access because man… Repairs typically run $0-$1,800. Severity: medium.