What does code P0E77 mean?

Q: What does code P0E77 mean?

Coolant Bypass Valve B Control Circuit/Open. P0E77 indicates the powertrain control module has detected an open circuit or excessive resistance on the control circuit for the coolant bypass valve B, which is used to route coolant away from the heater core or radiator during warm-up. The computer commands the valve to move but does not see the expected electrical feedback, so it sets this code and may default the valve to a safe position.

DTC codes / P0Exx · Hybrid propulsion / P0E77

P0E77Coolant Bypass Valve B Control Circuit/Open

P0E77 indicates the powertrain control module has detected an open circuit or excessive resistance on the control circuit for the coolant bypass valve B, which is used to route coolant away from the heater core or radiator during warm-up. The computer commands the valve to move but does not see the expected electrical feedback, so it sets this code and may default the valve to a safe position.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.