OBD-II code · Powertrain (generic, extended)
P26AF Engine Coolant Bypass Valve B Stuck/Open
The second coolant bypass valve is stuck in the open position. Coolant always bypasses the second radiator path.
Is it safe to drive with P26AF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve seized open by sediment
- PossibleBroken return spring
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Coolant Bypass Valve B, Thermostat Housing
Related codes
- P26ABEngine Coolant Bypass Valve A Stuck/Open
- P26BAEngine Coolant Bypass Valve C Stuck/Open
- P26C0Engine Coolant Bypass Valve D Stuck/Open
- P2E65Engine Coolant Bypass Valve E Stuck/Open
- P26ACEngine Coolant Bypass Valve B Control Circuit / Open
- P26ADEngine Coolant Bypass Valve B Control Circuit Low
- P26AEEngine Coolant Bypass Valve B Control Circuit High
- P26B0Engine Coolant Bypass Valve B Range/Performance
- P26B1Engine Coolant Bypass Valve A Stuck Closed
- P26B2Engine Coolant Bypass Valve B Stuck Closed
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.