P2CF2

Auxiliary Thermostat B Stuck Closed

Moderate severity

The auxiliary thermostat B is stuck closed. Coolant cannot flow through the affected branch, risking overheating in the bypassed path.

Common causes

Thermostat element failed
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $70-440
Wax pellet aged - element non-responsive
A plausible cause — test and verify before replacing parts.
medium
Typical part cost: $70-440
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P2CF2.
Unlock causes
Free forever · No credit card

First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

Get the full step-by-step diagnosis

Create a free Wrenchify account to unlock the rest for P2CF2.

Unlock diagnosis

Free forever · No credit card

Related codes

See related trouble codes

Create a free Wrenchify account to unlock the rest for P2CF2.

Unlock related codes

Free forever · No credit card

Frequently asked questions

What does P2CF2 mean?

P2CF2 means "Auxiliary Thermostat B Stuck Closed". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.

What are the most common causes of P2CF2?

thermostat element failed; wax pellet aged - element non-responsive; carbon or debris buildup preventing free movement — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

Get the full P2CF2 diagnosis for your vehicle

Year, make, model + step-by-step repair help — free plan included.

Diagnose P2CF2