Powertrain
Definition only
Lights the check engine lamp
P2CF2: Auxiliary Thermostat B Stuck Closed
Standardized SAE J2012 code · P2Cxx codes
What does P2CF2 mean?
The auxiliary thermostat B is stuck closed. Coolant cannot flow through the affected branch, risking overheating in the bypassed path.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Thermostat element failed
- Medium Wax pellet aged - element non-responsive
- Low Carbon or debris buildup preventing free movement
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2CF2 on the same make and model first.
P2CF2 in the community
Ask about P2CF2No one has posted about P2CF2 yet
Share your vehicle, the tool you used and what you tested — the first thread helps everyone who searches for this code.
Describe your P2CF2 problem