P2740Transmission

Transmission Fluid Temperature Sensor B Circuit

P2740 means the transmission control module detected a fault in the transmission fluid temperature sensor B circuit, so fluid temperature readings may be unreliable.

🚗 Drivable short term but get it checked. Bad fluid temperature data can affect shift timing and torque converter lockup.
MEDIUM
severity
Is P2740 really the problem on YOUR car?
Get a free AI diagnosis ranked by probability for your exact year, make, and model.
Run Free Diagnosis →

🎯 Top Causes, Ranked by Likelihood

#1Faulty fluid temperature sensor B$100-$350
40%
The sensor reads out of range or has failed.
#2Wiring or connector fault$100-$350
30%
Open, shorted, or corroded wiring disrupts the circuit.
#3Low or degraded fluid$100-$300
15%
Poor fluid contact affects readings in some designs.
#4TCM fault$500-$1200
15%
The module circuit that reads the sensor has failed.

🩺 Common Symptoms

💰 Repair Cost: DIY vs Shop

DIY Cost
$50-$400
Shop Cost
$150-$600

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose P2740

1Scan live data for fluid temperature readings
2Inspect the sensor wiring and connector
3Test sensor resistance across a temperature range
4Replace the sensor if it reads out of spec

❓ Frequently Asked Questions

Can I drive with P2740?
Yes for a short time, but shift timing and lockup may be affected, so get it diagnosed.
What does sensor B measure?
It measures transmission fluid temperature, which the module uses to adjust shifts and lockup.
How much to fix P2740?
Sensor replacement usually runs $150-$500 including labor.

🔗 Related Codes

P2741P2742P2743P0711
Don't guess. Know exactly what's wrong.
AmpAuto's AI ranks the real causes for your specific vehicle in 30 seconds.
Diagnose P2740 Free →