If a transmission fluid temperature sensor is sending the ECU an usually high voltage signal, it means that either the TFT sensor has failed, or the transmission has overheated. In either case, a P2743 DTC will be triggered.
How Serious is the Code?
If your vehicle has a P2743 diagnostic trouble code, you should get to the mechanic immediately. A P2743 DTC means that either the transmission has overheated, in which case you could be looking at serious internal damage. Or the TFT sensor has failed, which will prevent the ECU from knowing when the transmission actually is overheating. And it can also cause the ECU to put the transmission into Limp Mode, which can lock it into a single forward gear.
Symptoms of a P2743 DTC code include:
- Overheated transmission
- Smoke from transmission
- Slipping between gears
- Harsh, delayed or erratic gear changes
- Torque convertor lockup malfunctions
- Limp Mode
The most common causes of a P2743 trouble code include:
- Dirty transmission fluid and/or transmission filter
- Low transmission fluid levels
- Transmission fluid leak
- Corroded or damaged wiring connectors
- A short, damaged or corroded wiring
- Faulty transmission fluid temperature sensor
How to Diagnose the Code?
Dirty or low levels of transmission fluid can actually cause the gearbox to overheat, so this should be the first place to start in diagnosing a P2743 OBDII trouble code. The wiring and connectors on the transmission wiring harness should also be checked. If you can’t find any problems by this point, then the TFT sensor itself will need to be tested.
What Repairs Will Fix P2743?
- Change the transmission fluid and filter
- Repair transmission fluid leaks
- Find and fix any damaged wiring or shorts
- Replace any corroded or damaged connectors
- Replace transmission fluid temperature sensor
- P2740 – Transmission Fluid Temperature Sensor B Circ
- P2741 – Transmission Fluid Temperature Sensor B Circ Range/Performance
- P2742 – Transmission Fluid Temperature Sensor B Circ Low Voltage
- P2744 – Transmission Fluid Temperature Sensor B Circ Intermittent