OBD-II code · Powertrain (generic, extended)
P26BF Engine Coolant Bypass Valve D Control Circuit High
Voltage on the fourth coolant bypass valve control line is above the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P26BF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyControl wire shorted to B+
- PossibleOpen solenoid coil
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.8–3 h
- Emissions test
- Usually unaffected
- Parts involved
- Coolant Bypass Valve D, Solenoid, Wiring Harness
Related codes
- P2683Engine Coolant Bypass Valve A Control Circuit High
- P26AEEngine Coolant Bypass Valve B Control Circuit High
- P26B9Engine Coolant Bypass Valve C Control Circuit High
- P2E64Engine Coolant Bypass Valve E Control Circuit High
- P26BCEngine Coolant Bypass Valve C Stuck Closed
- P26BDEngine Coolant Bypass Valve D Control Circuit / Open
- P26BEEngine Coolant Bypass Valve D Control Circuit Low
- P26C0Engine Coolant Bypass Valve D Stuck/Open
- P26C1Engine Coolant Bypass Valve D Range/Performance
- P26C2Engine Coolant Bypass Valve D Stuck Closed
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.