Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that a part in the car that helps control the engine's temperature is not working properly. It's like a door that's supposed to open and close to let water through, but it's stuck open.
The P0E7F code indicates that the coolant bypass valve, which helps regulate the flow of coolant in the engine, is stuck in the open position or is not functioning as it should.
The coolant bypass valve B is responsible for directing coolant flow around the engine to maintain optimal operating temperatures. If this valve is stuck open, it can cause the engine to run too cool, affecting performance and emissions.
• Check Engine Light is on
• Engine running cooler than normal
• Decreased fuel efficiency
• Faulty coolant bypass valve
• Wiring issues or poor connection
• Malfunctioning control module
Coolant: A fluid that absorbs heat from the engine and dissipates it through the radiator.
Bypass Valve: A valve that controls the flow of coolant around the engine.
• Check for any stored trouble codes.
• Inspect the wiring and connections to the coolant bypass valve.
• Test the operation of the coolant bypass valve.
• Replace the coolant bypass valve.
• Repair or replace damaged wiring or connectors.
• Update or reprogram the control module if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $400
Moderate
• Toyota Prius
• Chevrolet Volt
• Ford Fusion Hybrid
• Regular maintenance checks
• Ensure proper coolant levels
• Inspect wiring for damage
Engine Performance
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional.
• Avoid driving long distances until repaired.
Check with the vehicle manufacturer for warranty coverage on emissions-related components.
This code has been reported in hybrid and plug-in hybrid vehicles where coolant management is crucial for efficiency.
Moderate – It should be addressed soon to prevent potential engine performance issues.
Driving with a malfunctioning coolant system can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle in park or neutral
The coolant bypass valve is typically located near the engine block or radiator, depending on the vehicle design.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to poor engine performance and increased emissions.
Q: Can I drive my car with this code?
A: It's best to have it checked soon, as driving with this issue can affect engine performance.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
View on Amazon
Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
View on Amazon
Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.