OBD-II code · Powertrain (generic)
P0E79 Coolant Bypass Valve B Control Circuit High
The coolant bypass valve B reports a control circuit high condition. 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 P0E79?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyWire shorted to B+
- PossibleCoil open
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- Parts involved
- Coolant Bypass Valve B, Wiring Harness
Related codes
- P0E75Coolant Bypass Valve A Control Circuit High
- P0E76Coolant Bypass Valve A Performance
- P0E77Coolant Bypass Valve B Control Circuit/Open
- P0E78Coolant Bypass Valve B Control Circuit Low
- P0E7ACoolant Bypass Valve B Performance
- P0E7BAuxiliary Cooling Coolant Temperature Sensor A Circuit
- P0E7CAuxiliary Cooling Coolant Temperature Sensor A Circuit Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.