P2740
Transmission Fluid Temperature Sensor B Circuit
Transmission
Generic OBD-II
Medium
What it means
P2740 means the control module has detected a fault in the circuit for transmission fluid temperature sensor 'B'. Without a trustworthy temperature reading, the transmission may adopt firmer or more conservative shift and torque-converter behavior. The car remains drivable and still starts; the concern is degraded shift quality and lost temperature protection.
Medium
Can I keep driving? Drivable, but the transmission may shift firmly or use a protective strategy because it can't read fluid temperature accurately.
Common symptoms
What you'll notice
- Check-engine light on
- Firm or altered shift behavior
- Possible reduced or delayed torque-converter lockup
- Inaccurate transmission-temperature reading
Common causes
Most likely first
- Faulty transmission fluid temperature sensor BLikely
- Open or shorted sensor wiringCommon
- Corroded or loose connector at the transmissionCommon
- Contaminated fluid affecting the sensorLess often
- Faulty PCM/TCMLess often
How to diagnose & fix
Work through it in order
- Scan and compare the sensor's reading to the actual temperature.
- Inspect the sensor connector and wiring for an open, short, or corrosion.
- Measure the sensor's resistance against the temperature spec.
- Replace the temperature sensor if it is out of range.
- Repair wiring as needed. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2740?+
Generally yes. The car runs, but the transmission may shift oddly. Fix it to restore normal shift scheduling and protect the transmission.
Can I just clear P2740?+
It comes back until the sensor or its wiring is repaired.
Related codes
Often seen with P2740
Read & clear P2740 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX