Powertrain
generic / SAE
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.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number6 / A8
Possible causes
- Sensor connector not fully seated high
- Harness chafed near thermostat housing medium
- Connector with intermittent contact under vibration low
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 60–350 €
- Estimated time: 0.5–2 h
- Component: bypass position sensor a
- Component: wiring harness
- MIL / check engine light
Sources
References
sae:J2012