What it means
Coolant bypass valve B is detected as stuck in the closed position. The module sets this code when valve feedback or system behavior indicates that it remains closed when it should move.
How it works
Coolant bypass valve B directs coolant through or around part of the thermal-management system. The module monitors valve position or system response and sets P0E80 when valve B remains closed when it should open; mechanical jamming, debris, actuator failure, or a wiring fault can prevent the required movement.
Common causes
Most likely first.
- Valve jammed or internally damaged
- Debris or restriction in the valve
- Failed valve actuator
- Wiring or connector fault
Symptoms
- Hybrid or EV warning light
- Reduced power
- Battery or motor temperature warning
- Cabin heating or cooling may be reduced
How to diagnose it
- Record freeze-frame data and check live valve B command, position feedback if available, and coolant temperatures to identify when the module expected the valve to open.
- Inspect valve B’s connector and harness for damaged wires, corrosion, loose pins, or other faults that could prevent the open command.
- Check coolant level and inspect the accessible valve B coolant path for debris, leakage, or blockage.
- Use a scan-tool actuator command if supported and compare the valve B response with the manufacturer’s procedure.
- If the electrical command reaches the actuator but valve B remains closed, test its actuator and mechanical movement according to the manufacturer’s instructions.
Common fixes
- Repair damaged valve B wiring or connector terminals.
- Correct low coolant and repair the cause of any leak.
- Remove a confirmed blockage from the valve B coolant path using the manufacturer’s procedure.
- Replace valve B if it is jammed closed or its actuator has failed.
Can I keep driving?
Avoid heavy driving if reduced power or a battery or motor temperature warning appears, since a closed valve B can restrict coolant flow. Stop safely if a temperature warning appears.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.