What Does P2679 Mean?
The coolant degassing valve control circuit voltage is lower than expected. A short to ground or excessive current draw prevents proper valve control.
Common Causes
40%
Short to ground in degassing valve control circuit wiring
30%
Failed degassing valve solenoid with internal short
15%
Water intrusion or corrosion in connector causing short
10%
Chafed wiring harness contacting ground
5%
Failed ECM driver circuit
Diagnostic Steps
1
Step 1: Disconnect degassing valve solenoid and measure coil resistance
2
Step 2: With valve disconnected, test control circuit for short to ground using ohmmeter
3
Step 3: Inspect wiring harness for damage, especially near heat sources or sharp edges
4
Step 4: Check connector for moisture, corrosion, or pushed-out terminals
5
Step 5: If wiring is good, replace solenoid; if short persists, test ECM output
Estimated Repair Cost
$200 - $650
Parts + labor, varies by vehicle and location
The coolant degassing valve control circuit voltage is lower than expected. A short to ground or excessive current draw prevents proper valve control.
The most common cause of P2679 (Coolant Degassing Valve Control Circuit Low) is: Short to ground in degassing valve control circuit wiring
Typical repair costs for P2679 range from $200 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Risk of overheating due to air pockets in cooling system. Avoid extended driving until repaired to prevent engine damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2679 to identify the root cause.
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Quick Info
Category
Powertrain
System
Cooling System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
