Powertrain
generic / SAE
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).
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number7 / CB
Possible causes
- Thermostat stuck open high
- Thermostat stuck closed medium
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
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 150–700 €
- Estimated time: 0.5–2.5 h
- Component: transmission fluid thermostat
- Component: transmission cooler
- MIL / check engine light
Sources
References
sae:J2012