OBD-II code · Powertrain (generic, extended)
P26B1 Engine Coolant Bypass Valve A Stuck Closed
The coolant bypass valve A is stuck closed. Coolant cannot bypass the radiator during warm-up so warm-up takes longer and emissions in the warm-up phase rise.
Is it safe to drive with P26B1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve seized closed by debris
- PossibleActuator linkage jammed in closed position
- Less likelyCarbon or debris buildup preventing free movement
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- Parts involved
- Coolant Bypass Valve A, Thermostat Housing
Related codes
- P26B2Engine Coolant Bypass Valve B Stuck Closed
- P26BCEngine Coolant Bypass Valve C Stuck Closed
- P26C2Engine Coolant Bypass Valve D Stuck Closed
- P2E67Engine Coolant Bypass Valve E Stuck Closed
- P26AEEngine Coolant Bypass Valve B Control Circuit High
- P26AFEngine Coolant Bypass Valve B Stuck/Open
- P26B0Engine Coolant Bypass Valve B Range/Performance
- P26B3Fuel Shutoff Valve A Control Circuit Performance/Stuck Off
- P26B4Fuel Shutoff Valve A Control Circuit Stuck On
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.