OBD-II code · Powertrain (generic, extended)
P26A3 Engine Coolant Bypass Valve A Range/Performance
The coolant bypass valve A responds to commands but the resulting coolant temperature behaviour is not as expected. Possibly stuck partially open or contaminated bore.
Is it safe to drive with P26A3?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve partially stuck by sediment
- PossibleWeak return spring fails to close fully
- Less likelySensor element aged beyond calibration window
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–3.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Coolant Bypass Valve A, Thermostat Housing
Related codes
- P26B0Engine Coolant Bypass Valve B Range/Performance
- P26BBEngine Coolant Bypass Valve C Range/Performance
- P26C1Engine Coolant Bypass Valve D Range/Performance
- P2E66Engine Coolant Bypass Valve E Range/Performance
- P26A0Exhaust Aftertreatment Glow Plug Performance
- P26A1Exhaust Aftertreatment Glow Plug Circuit Low
- P26A2Exhaust Aftertreatment Glow Plug Circuit High
- P26A4Engine Coolant Bypass Valve A Position Sensor Circuit
- P26A5Engine Coolant Bypass Valve A Position Sensor Circuit Range/Performance
- P26A6Engine Coolant Bypass Valve A Position Sensor Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.