OBD-II code · Powertrain (generic, extended)
P26A8 Engine Coolant Bypass Valve A Position Sensor Circuit Intermittent/Erratic
The bypass valve A position sensor signal jumps or drops out intermittently. 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 P26A8?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor connector not fully seated
- PossibleHarness chafed near thermostat housing
- Less likelyConnector with intermittent contact under vibration
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Bypass Position Sensor A, Wiring Harness
Related codes
- P2AABEngine Coolant Bypass Valve B Position Sensor Circuit Intermittent/Erratic
- P26A5Engine Coolant Bypass Valve A Position Sensor Circuit Range/Performance
- P26A6Engine Coolant Bypass Valve A Position Sensor Circuit Low
- P26A7Engine Coolant Bypass Valve A Position Sensor Circuit High
- P26A9Engine Coolant Bypass Valve A Position Sensor Stop/Minimum Stop Performance
- P26AAEngine Coolant Bypass Valve A Position Sensor Maximum Stop Performance
- P26ABEngine Coolant Bypass Valve A Stuck/Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.