P26A3 on Subaru
Engine Coolant Bypass Valve "A" Range/Performance
P26A3 on Subaru vehicles indicates engine coolant bypass valve "a" range/performance. Au7o has documented this code across 2 Subaru models — most commonly on Legacy, Outback. This code means the computer found that engine coolant bypass valve 'A' is not performing within its expected range. This valve controls coolant flow through the engine to manage warm-up and operating temperature, staying closed when the engine is cold and opening as it heats up for consistent temperature. A range/performance fault can lead to slow warm-up, poor heater output, or temperature regulation problems, so it should be checked to avoid running too hot or too cold. Typical repair costs on Subaru range from $900 to $2,200, depending on the specific model and root cause.
Common Causes of P26A3
- •Faulty or sticking coolant bypass valve/solenoid
- •Clogged or restricted coolant passages/lines
- •Wiring or connector damage and corrosion
- •Low coolant level or air in the cooling system
- •Faulty coolant temperature sensor input
- •PCM/ECM fault (rare)
P26A3 on Subaru by Model
Subaru Legacy(1 issue)
- Thermo Control Valve Failure Causing Check Engine Light, Poor Heater Performance, and Possible Overheating2021-2024
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.
Subaru Outback(1 issue)
- Thermo Control Valve Failure Causing Check Engine Light and Overheating Risk2020-2023
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.
Looking for P26A3 on a different make?
View P26A3 across all makes →Frequently Asked Questions
What does P26A3 mean on Subaru?▼
P26A3 stands for "Engine Coolant Bypass Valve "A" Range/Performance." This code means the computer found that engine coolant bypass valve 'A' is not performing within its expected range. This valve controls coolant flow through the engine to manage warm-up and operating temperature, staying closed when the engine is cold and opening as it heats up for consistent temperature. A range/performance fault can lead to slow warm-up, poor heater output, or temperature regulation problems, so it should be checked to avoid running too hot or too cold. On Subaru specifically, this code is documented across 2 models.
What causes P26A3 on Subaru vehicles?▼
Common causes on Subaru: Faulty or sticking coolant bypass valve/solenoid, Clogged or restricted coolant passages/lines, Wiring or connector damage and corrosion, Low coolant level or air in the cooling system, Faulty coolant temperature sensor input. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P26A3 on a Subaru?▼
Repair costs on Subaru range from $900 to $2,200, depending on the specific model and root cause.
Which Subaru models have P26A3 documented?▼
Au7o has documented P26A3 on 2 Subaru models: Legacy, Outback.