A transmission fluid temperature sensor operates by sending the computer an an electrical signal based on the temperature of the ATF. Typically, the lower the voltage the higher the temperature of the transmission fluid is. However, a P2742 DTC means that either there’s an electrical problem that is causing the TFT sensor to send back an unusually low voltage signal. Or, the transmission fluid has in fact overheated.
How Serious is the Code?
A P2742 diagnostic trouble code is actually quite serious. If the transmission has in fact overheated, there could be significant internal damage. If the TFT sensor has failed, then the ECU can put the transmission into Limp Mode, which will be restricted to a single forward gear.
Some common symptoms of a P2742 DTC include:
- Overheating transmission
- Slipping between the gears
- Delayed, unusually harsh or erratic shifts
- Torque convertor lockup clutch malfunction
- Limp Mode
The typical causes of a P2742 trouble code include:
- Dirty transmission fluid and/or a clogged transmission filter
- Low transmission fluid level
- Transmission fluid leak
- Damaged or corroded wiring connectors
- Damaged wiring, a short or corrosion
- Failed transmission fluid temperature sensor
How to Diagnose the Code?
The first thing that should be checked when trying to diagnose a P2742 OBDII trouble code, is the transmission fluid itself. If it’s low or dirty, that could increase the operating temperature of the transmission, which can cause both the TFT sensor not to work properly, and an overheating situation.
What Repairs Will Fix P2742?
- Change dirty transmission fluid
- Change transmission filter
- Fix transmission fluid leaks
- Fix shorts in the wiring and/or damage
- Fix corroded or damaged connectors
- Install a new transmission fluid temperature sensor
- P2740 – Transmission Fluid Temperature Sensor B Circ
- P2741 – Transmission Fluid Temperature Sensor B Circ Range/Performance
- P2743 – Transmission Fluid Temperature Sensor B Circ High Voltage
- P2744 – Transmission Fluid Temperature Sensor B Circ Intermittent