P2740 code meaning
Transmission Fluid Temperature Sensor B Circuit
Powertrain system Generic code P27xx codes Check engine light
What P2740 means
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.
P2740 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P2740
- 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
Common causes of P2740
- Most likelyLoose, corroded or damaged connector or lead to sensor B
- PossibleSensor B thermistor open or shorted internally
- Less likelyFaulty input stage in the transmission control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Trans fluid temp sensor bWiring harness
What each part of P2740 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 7 | Area: transmission. |
| 40 | The exact fault in that area. |
What to do next
- Note P2740 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2740
What does P2740 mean?
P2740 means "Transmission Fluid Temperature Sensor B Circuit". P2740 is the umbrella circuit code for a second transmission fluid temperature sensor, labelled B. It is a generic code, so it means the same on every make.
Is it safe to drive with P2740?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2740 fail an emissions test?
P2740 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P2740 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P2740 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.