Transmission Fluid Temperature Sensor B Circuit High
What it means
P2743 means the transmission fluid temperature sensor 'B' circuit is reading high — a voltage that usually points to an open or high-resistance circuit, making the fluid look implausibly cold to the TCM. Because shift timing and torque-converter lock-up depend on fluid temperature, the transmission may shift differently or hold off lock-up as a precaution. It's a sensor/wiring fault and does not prevent the engine from starting.
Can I keep driving? Usually driveable — the transmission may alter its shift timing or lock-up as a precaution, but there's no immediate danger to driving.
Common symptoms
What you'll notice
- Check-engine light on
- Altered, harsh, or delayed shifts
- Torque converter lock-up may be disabled
- Reduced fuel economy
Common causes
Most likely first
- Faulty transmission fluid temperature sensor B (reads implausibly cold)Likely
- Open or high-resistance wiring in the sensor circuitCommon
- Corroded or loose connectorCommon
- Internal transmission wiring harness faultLess often
- Faulty TCM/PCMLess often
How to diagnose & fix
Work through it in order
- Scan and compare the reported fluid temperature with actual conditions.
- Inspect the sensor connector and wiring for an open or high resistance.
- Measure the sensor's resistance and check it against a temperature chart.
- Repair the internal harness or connector as needed.
- Replace the sensor if it fails testing, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2743?+
Can I just clear P2743?+
Related codes
Often seen with P2743
Read & clear P2743 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.