OBD Guide

P2CEF

Auxiliary Thermostat A Stuck Open

P2CEF is an OBD-II diagnostic trouble code meaning: Auxiliary Thermostat A Stuck Open. Common causes: additional thermostat malfunction, problems with the thermostat electrical connections. Estimated repair cost: $17–56.

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

Symptoms

  • The engine takes a long time to warm up
  • Increased fuel consumption
  • Unstable engine temperature
  • Reduced interior heating efficiency
  • Check Engine light comes on

Causes

  • Additional thermostat malfunction
  • Problems with the thermostat electrical connections
  • Open or short circuit in thermostat control circuit
  • Mechanical jamming of the thermostat
  • Problems with the engine control unit

How to Fix

  1. Check thermostat electrical connections
  2. Test the thermostat operation
  3. Replace a faulty thermostat
  4. Check the integrity of the control circuit
  5. Reset the error code and test drive

Related codes

Error P2CEF by Vehicle Brand

FAQ

What does the P2CEF code mean?

P2CEF is an OBD-II diagnostic trouble code that indicates: Auxiliary Thermostat A Stuck Open

What causes a P2CEF error code?

The most common causes of P2CEF include: Additional thermostat malfunction; Problems with the thermostat electrical connections; Open or short circuit in thermostat control circuit; Mechanical jamming of the thermostat.

How do I fix a P2CEF diagnostic trouble code?

To fix P2CEF: Check thermostat electrical connections. Test the thermostat operation. Replace a faulty thermostat. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2CEF?

Yes, but get it checked soon

How much does it cost to fix P2CEF?

The estimated repair cost for P2CEF is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat