P2678 Fault Code

Coolant Degassing Valve Control Circuit/Open

• What does that mean?
• Symptoms
• Causes
• Solutions

The P2678 fault code indicates an issue with the coolant degassing valve control circuit, which may be open or malfunctioning. This valve plays a crucial role in managing coolant pressure and ensuring efficient engine operation. When this code is triggered, it's essential to address it promptly to avoid further engine problems.

What are the symptoms of the P2678 code?

Common symptoms associated with this fault code may include:

• Overheating engine due to improper coolant circulation.
• Warning lights on the dashboard, particularly the check engine light.
• Changes in engine performance, such as misfires or decreased power.
• Coolant leaks around the degassing valve.

What causes the P2678 code?

Possible causes of the P2678 code include:

• A faulty coolant degassing valve.
• Wiring issues like short circuits or open connections in the control circuit.
• A malfunctioning engine control module (ECM) that fails to control the valve properly.
• Corrosion or damage in the connectors related to the coolant system.

How to fix P2678?

To resolve the P2678 fault code, consider the following actions:

• Inspect the coolant degassing valve for any physical damage and replace if necessary.
• Check the wiring and connectors for the valve, ensuring there are no breaks or corrosion.
• Test the engine control module for proper functionality and reprogram or replace if it is faulty.
• Clear the fault code and monitor for any reoccurrences or additional symptoms.