OBD Guide

P0E79

Coolant Bypass Valve A Control Stuck/Open

P0E79 is an OBD-II diagnostic trouble code meaning: Coolant Bypass Valve A Control Stuck/Open. Common causes: stuck coolant valve, open or short circuit in control circuit. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Unstable engine temperature
  • Poor interior heating
  • Extended engine warm-up time
  • Check Engine light comes on
  • Possible errors in related systems

Causes

  • Stuck coolant valve
  • Open or short circuit in control circuit
  • Problems with the engine control unit
  • Valve contaminated or corroded
  • Valve solenoid malfunction

How to Fix

  1. Check valve electrical circuit
  2. Test the resistance of the electromagnet winding
  3. Clean or replace coolant valve
  4. Check thermostat operation
  5. Reset error and test drive

Related codes

Error P0E79 by Vehicle Brand

FAQ

What does the P0E79 code mean?

P0E79 is an OBD-II diagnostic trouble code that indicates: Coolant Bypass Valve A Control Stuck/Open

What causes a P0E79 error code?

The most common causes of P0E79 include: Stuck coolant valve; Open or short circuit in control circuit; Problems with the engine control unit; Valve contaminated or corroded.

How do I fix a P0E79 diagnostic trouble code?

To fix P0E79: Check valve electrical circuit. Test the resistance of the electromagnet winding. Clean or replace coolant valve. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0E79?

Yes, but get it checked soon

How much does it cost to fix P0E79?

The estimated repair cost for P0E79 is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat