P2682 on Subaru: How to Diagnose & Fix
Engine Coolant Bypass Valve "A" Control Circuit Low
1 Subaru model · 1 documented issue · 1 critical · $900-$1,800 repair
P2682 on Subaru by model: symptoms, diagnosis and fix
Multiple 2020-2023 Outback owners with the 2.5L FB25 engine report failure of the thermo control valve assembly, which can trigger a check engine light, disable normal coolant flow control, and in some cases lead to overheating or poor heater performance. Subaru issued a warranty extension and service communications because the valve's internal position sensor/motor can fail. Owners commonly see the problem well before 100,000 miles, often with no prior cooling-system symptoms.
Common Symptoms
- check engine light
- engine coolant temperature warning
- poor cabin heat
- engine running cooler or hotter than normal
- reduced fuel economy
- cooling fan behavior changes
How to Fix
Diagnosis usually begins with stored cooling-system related DTCs and confirmation of improper thermo control valve operation using scan data. The standard repair is replacement of the thermo control valve assembly, followed by coolant refill/bleed and code clearing. If the vehicle has overheated, the cooling system should be pressure-tested and checked for secondary damage.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Subaru 21319AA040 Thermo Control Valve Assembly
updated valve assembly after diagnosis and warranty-extension check Fitment/availability: 2020-2025 Outback 2.5-liter FB25 only; not the 2.4-liter turbo, confirm VIN and coverage Fitment/availability: ships in 1-2 business days with Add …
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Owner tips & cautions
- TipIf the CEL appears with cooling-related codes, avoid repeated long trips until coolant temperature behavior is confirmed; some owners caught the issue early before overheating by scanning codes immediately.
- TipAfter replacement, owners recommend confirming the cooling system was properly vacuum-filled or bled to avoid trapped air and erratic heater performance.
Sources for this issue (1)
P2682 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P2682 mean on a Subaru?
P2682 stands for "Engine Coolant Bypass Valve "A" Control Circuit Low." This code is set when the engine control module detects low voltage on the control circuit for engine coolant bypass valve "A". This electronically controlled valve directs coolant flow to speed engine warm-up and supply heat to the heater core. A circuit fault can leave the valve in the wrong position, affecting warm-up time, heater output, and potentially engine temperature regulation. It usually points to an electrical problem in the valve or its wiring rather than the cooling system itself. On Subaru it is documented across 1 model: Outback.
What are the most common causes of P2682?
The most common causes of P2682 are: Faulty coolant bypass valve solenoid (internal short), Corroded, shorted, or open wiring/connectors, Poor electrical connection at the valve, Coolant contamination of the connector, Failed driver circuit inside the PCM/ECM, Damaged wiring harness. The specific cause varies by vehicle.
How much does it cost to fix P2682 on a Subaru?
Published repair estimates on Subaru range from $900 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P2682 on a different make?
View P2682 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.