U063B
Lost Communication With Coolant Bypass Valve Actuator A
U063B is an OBD-II diagnostic trouble code meaning: Lost Communication With Coolant Bypass Valve Actuator A. Common causes: open or short circuit in valve circuit, bypass solenoid valve malfunction. Estimated repair cost: $17–56.
Symptoms
- Check Engine light comes on
- Reduced engine power
- Incorrect operation of the cooling system
- Possible engine overheating
- The car may go into emergency mode
Causes
- Open or short circuit in valve circuit
- Bypass solenoid valve malfunction
- Problems with the wiring harness or connectors
- Engine ECU malfunction
- Contact corrosion
How to Fix
- Check the integrity of the bypass valve circuit
- Inspect connectors and wiring harness for damage
- Check valve resistance (compare with nominal)
- Replace faulty bypass valve if necessary
- Reset the error and check if it returns
Related codes
Error U063B by Vehicle Brand
FAQ
What does the U063B code mean?
U063B is an OBD-II diagnostic trouble code that indicates: Lost Communication With Coolant Bypass Valve Actuator A
What causes a U063B error code?
The most common causes of U063B include: Open or short circuit in valve circuit; Bypass solenoid valve malfunction; Problems with the wiring harness or connectors; Engine ECU malfunction.
How do I fix a U063B diagnostic trouble code?
To fix U063B: Check the integrity of the bypass valve circuit. Inspect connectors and wiring harness for damage. Check valve resistance (compare with nominal). For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U063B?
Limited driving only, diagnose soon
How much does it cost to fix U063B?
The estimated repair cost for U063B is $17–56. Actual cost depends on your vehicle, location, and labor rates.
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