P2740Transmission Fluid Temperature Sensor B Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2740 is the umbrella circuit code for a second transmission fluid temperature sensor, labelled B. The control module supplies the thermistor with a reference voltage and flags an electrical fault when the returned signal leaves its plausible window, without separating short from open. Where B is documented, it sits outside the sump: Ford's TR9070 dual-clutch gearbox and a GM dual-clutch module of 2023/24 both use it for the fluid leaving the cooler, but report electrical faults through the split codes P2742/P2743 rather than P2740. No manufacturer publishes P2740 itself. Without a valid B value the module relies on sensor A or a default, so cooler control and hot-fluid protection get coarser; shifting usually remains normal.
- What you may notice
- Warning lamp or transmission message
- Fluid temperature B shows an implausible fixed value on the scan tool
- Cooler or hot-fluid protection works with a substitute value
- Likely causes
- LikelyLoose, corroded or damaged connector or lead to sensor B
- PossibleSensor B thermistor open or shorted internally
- RareFaulty input stage in the transmission control module
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.