Coolant Degassing Valve Control Circuit Low
The P2679 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the control circuit of the coolant degassing valve. This valve is responsible for venting air from the cooling system to prevent air pockets that can cause overheating. A low circuit voltage typically points to a short to ground, open circuit, or a faulty valve. This issue can lead to improper cooling system operation and potential engine overheating.
01. Most Common Causes
- Faulty coolant degassing valve
- Short to ground in the control circuit
- Open circuit or damaged wiring/connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine overheating or temperature fluctuations
- Coolant loss or visible leaks
- Poor heater performance
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect the coolant degassing valve and its wiring for damage or corrosion.
Step 3: Test the valve's resistance with a multimeter (specs vary by vehicle).
Step 4: Check for voltage at the valve connector with the ignition on; should be near battery voltage.
Step 5: If voltage is low, check for shorts or opens in the circuit; repair as needed.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can lead to engine overheating and serious damage. Have the vehicle inspected promptly.
How much does it cost to fix?▼
Repair costs typically range from $50 to $150 for parts and labor, depending on the cause and vehicle model.