What it means
The battery charger coolant control valve control circuit voltage is above the expected range. The valve may not regulate coolant flow as commanded, which can affect charger cooling or charging operation depending on the vehicle.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery charger coolant control valve directs coolant through the charger’s cooling circuit. The control module monitors the valve’s electrical control circuit and sets P0DFF when its voltage is higher than expected, which can prevent the valve from regulating coolant flow as commanded.
Common causes
Most likely first.
- Wire shorted to B+
- Coil open
- Connector pins corroded - high contact resistance
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Record freeze-frame data and review charger coolant valve command and feedback data to identify when the high-circuit fault appears.
- With the vehicle safely powered down, inspect the valve connector and harness for corrosion, loose pins, or insulation damage that could expose the control wire to battery voltage.
- Check connector contacts for corrosion or poor fit that could interrupt the circuit.
- Use the vehicle wiring diagram to test the control wire for a short to B+ and verify continuity as specified by the manufacturer.
- Measure the valve coil and circuit response against the manufacturer’s specification to determine whether the coil is open or the harness is at fault.
Common fixes
- Clean and secure corroded or loose valve connector terminals.
- Repair the control wire if it is shorted to B+ or damaged.
- Replace the battery charger coolant control valve if its coil is open.
- Clear the code and verify valve operation and charging behavior.
Can I keep driving?
Charging may be slow, interrupted, or unavailable, and the charger may not receive the intended cooling. Avoid repeated charging attempts if the vehicle reports a high-voltage system fault, and have the circuit diagnosed promptly.
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.