OBD-II code · Powertrain (generic, extended)
P26B9 Engine Coolant Bypass Valve C Control Circuit High
Voltage on the third 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 P26B9?
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 C, Solenoid, Wiring Harness
Related codes
- P2683Engine Coolant Bypass Valve A Control Circuit High
- P26AEEngine Coolant Bypass Valve B Control Circuit High
- P26BFEngine Coolant Bypass Valve D Control Circuit High
- P2E64Engine Coolant Bypass Valve E Control Circuit High
- P26B6Fuel Shutoff Valve B Control Circuit Stuck On
- P26B7Engine Coolant Bypass Valve C Control Circuit / Open
- P26B8Engine Coolant Bypass Valve C Control Circuit Low
- P26BAEngine Coolant Bypass Valve C Stuck/Open
- P26BBEngine Coolant Bypass Valve C Range/Performance
- P26BCEngine Coolant Bypass Valve C Stuck Closed
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.