OBD Guide

P2678

Coolant Degassing Valve Control Circuit/Open

P2678 is an OBD-II diagnostic trouble code meaning: Coolant Degassing Valve Control Circuit/Open. Common causes: open or short circuit in control circuit, degassing valve malfunction. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Engine overheating
  • Unstable engine operation
  • Increased fuel consumption
  • Check Engine Light Is On
  • Poor interior heating

Causes

  • Open or short circuit in control circuit
  • Degassing valve malfunction
  • Problems with the engine control unit
  • Corrosion of contacts or connectors
  • Wiring harness damage

How to Fix

  1. Check the integrity of the valve control circuit
  2. Check the resistance of the degassing valve
  3. Inspect connectors and contacts for corrosion
  4. Replace degassing valve if necessary
  5. Check the operation of the system after repair

Related codes

Error P2678 by Vehicle Brand

FAQ

What does the P2678 code mean?

P2678 is an OBD-II diagnostic trouble code that indicates: Coolant Degassing Valve Control Circuit/Open

What causes a P2678 error code?

The most common causes of P2678 include: Open or short circuit in control circuit; Degassing valve malfunction; Problems with the engine control unit; Corrosion of contacts or connectors.

How do I fix a P2678 diagnostic trouble code?

To fix P2678: Check the integrity of the valve control circuit. Check the resistance of the degassing valve. Inspect connectors and contacts for corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2678?

Limited driving only, diagnose soon

How much does it cost to fix P2678?

The estimated repair cost for P2678 is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat