OBD-II code · Powertrain (generic)
P0E77 Coolant Bypass Valve B Control Circuit/Open
The coolant bypass valve B reports a control circuit/open condition.
Is it safe to drive with P0E77?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyOpen in control wire
- PossibleCoil open
- Less likelyPin pushed back out of connector body
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
- P0E73Coolant Bypass Valve A Control Circuit/Open
- P0E74Coolant Bypass Valve A Control Circuit Low
- P0E75Coolant Bypass Valve A Control Circuit High
- P0E76Coolant Bypass Valve A Performance
- P0E78Coolant Bypass Valve B Control Circuit Low
- P0E79Coolant Bypass Valve B Control Circuit High
- P0E7ACoolant Bypass Valve B Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.