P2680: Coolant Degassing Valve Control Circuit High

What it means

Voltage on the coolant degassing valve control line is above the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

At a glance

• Usually lights the check-engine light

How it works

The coolant degassing valve control circuit operates a valve that helps release trapped air from the cooling system. The control module monitors the circuit voltage, and this code sets when it reads above the allowed range.

Common causes

Most likely first.

1. Control wire shorted to B+
2. Open solenoid coil
3. Connector pins corroded - high contact resistance

Symptoms

• Check-engine light
• Engine may take longer to reach operating temperature

How to diagnose it

1. Record freeze-frame data and check scan-tool coolant temperature and degassing-valve command data to see when the high circuit reading occurs.
2. With the engine cool, inspect the valve connector and nearby wiring for corrosion, water, heat damage, or chafing.
3. Check the control wire for a short to battery positive and inspect connector terminal fit using the manufacturer's wiring information.
4. Test the valve solenoid coil for an open circuit and compare the result with the manufacturer's specification.
5. If the circuit and valve check out, verify the control module's circuit output using the manufacturer's diagnostic procedure.

Common fixes

• Repair a control wire shorted to battery positive.
• Clean or repair corroded or loose degassing-valve connector terminals.
• Replace the degassing valve if its solenoid coil is open.
• Repair the control module circuit only if testing confirms an output fault.

Can I keep driving?

A longer warm-up may occur, but monitor the temperature gauge closely and avoid driving if the engine overheats or coolant is lost. A degassing fault can impair air removal from the cooling system.