OBD-II code · Powertrain (generic)
P07CB Transmission Fluid Thermostat Performance
The transmission fluid thermostat (similar in function to a coolant thermostat — opens at a calibrated temperature to route ATF through the cooler) does not regulate temperature within the expected band. Either stuck open (ATF stays cold, friction modifier ineffective) or stuck closed (ATF overheats, oxidising the fluid).
Is it safe to drive with P07CB?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyThermostat stuck open
- PossibleThermostat stuck closed
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–2.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Transmission Fluid Thermostat, Transmission Cooler
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.