P0E78
Coolant Bypass Valve A Control Circuit Range/Performance
P0E78 is an OBD-II diagnostic trouble code meaning: Coolant Bypass Valve A Control Circuit Range/Performance. Common causes: coolant bypass valve malfunction, open or short circuit in control circuit. Estimated repair cost: $17–56.
Symptoms
- Unstable engine operation
- Increased engine temperature
- Reduced interior heating efficiency
- Check Engine light comes on
- Possible misfires
Causes
- Coolant bypass valve malfunction
- Open or short circuit in control circuit
- Poor contact in circuit connectors
- Engine control unit (ECU) malfunction
- Valve is dirty or clogged
How to Fix
- Check the condition of the coolant bypass valve
- Check the integrity of the control circuit and connectors
- Check valve resistance and operation
- If necessary, replace the valve or repair the circuit
- Reset the error code and check if it returns
Related codes
Error P0E78 by Vehicle Brand
FAQ
What does the P0E78 code mean?
P0E78 is an OBD-II diagnostic trouble code that indicates: Coolant Bypass Valve A Control Circuit Range/Performance
What causes a P0E78 error code?
The most common causes of P0E78 include: Coolant bypass valve malfunction; Open or short circuit in control circuit; Poor contact in circuit connectors; Engine control unit (ECU) malfunction.
How do I fix a P0E78 diagnostic trouble code?
To fix P0E78: Check the condition of the coolant bypass valve. Check the integrity of the control circuit and connectors. Check valve resistance and operation. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P0E78?
Yes, but get it checked soon
How much does it cost to fix P0E78?
The estimated repair cost for P0E78 is $17–56. Actual cost depends on your vehicle, location, and labor rates.
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