A P2740 DTC gets triggered when the ECU detects a problem with the transmission fluid temperature sensor labeled B. The TFT sensor tells the computer what the temperature of the transmission fluid currently is. If the information coming back from this sensor does not meet the preset computer parameters, then either the transmission fluid is getting too hot, or the TFT sensor is malfunctioning.
How Serious is the Code?
The P2740 diagnostic trouble code is pretty serious, because it means either the transmission is overheating, or the computer can’t tell when it is overheating. In either case, there can be a serious internal damage from the excess heat, or the transmission may think that it’s overheating because of the failing transmission fluid temperature sensor, which can cause the ECU to put the transmission into Limp Mode (the transmission is locked into a single forward gear).
Symptoms of a P2740 include:
- Harsh, delayed or erratic shifts
- Transmission overheating
- Torque convertor lockup malfunction
- Limp Mode
Common causes of a P2740 DTC include:
- Low transmission fluid level
- Dirty transmission fluid
- Failed transmission fluid temperature sensor
- A short, damage, or corrosion in the wiring or connectors
How to Diagnose the Code?
One of the first things that should be done when diagnosing a P2740 OBDII trouble code, is to check the level and condition of the transmission fluid. Next, the wiring and connectors on the transmission wiring harness should be inspected for signs of damage and corrosion. If no problems are found up to this point, then the TFT sensor itself will need to be tested with a volt meter.
What Repairs Will Fix P2740?
- Replace the transmission fluid temperature sensor
- Change the transmission fluid
- Repair transmission fluid leaks
- Repair a short, damage, or corrosion in the wiring or connectors
- P2741 – Transmission Fluid Temperature Sensor B Circ Range/Performance
- P2742 – Transmission Fluid Temperature Sensor B Circ Low Voltage
- P2743 – Transmission Fluid Temperature Sensor B Circ High Voltage
- P2744 – Transmission Fluid Temperature Sensor B Circ Intermittent