P0710 – Transmission fluid temperature (TFT) sensor circuit malfunction

By John Kershaw (Contact Me)
Last Updated 2016-01-15
Ed.D, PhD Philosophy, BSME

Table of Contents

1. What Does Code P0710 Mean?
2. What are the common causes of code P0710 ?
3. What are the symptoms of code P0710 ?
4. Codes Related to P0710
5. Get Help with P0710

What Does Code P0710 Mean?

The TFT (transmission fluid temperature) sensor is part of the automatic transmission fluid pressure (TFP) manual valve position switch and is a thermistor that changes value based on temperature. The TFT is an NTC (negative-temperature coefficient), which means that as the temperature increases, the resistance decreases, and as the temperature decreases, the resistance increases. The PCM (powertrain control module) supplies a 5-volt reference signal to the sensor and measures the voltage drop in the circuit. When the transmission fluid is cold, the sensor resistance is high and the PCM detects high signal voltage. As the fluid temperature warms to a normal operating temperature, the resistance becomes less and the signal voltage decreases. This sensor is used by the PCM or TCM to detect the temperature of the automatic transmission fluid. This signal is used to determine the best shift points and to regulate line pressure. It will cause the control module (PCM or TCM) to engage the TCC (torque converter clutch) sooner and disable overdrive, to help reduce the fluid temperature if it reaches higher than normal.

NOTE: Whenever diagnosing a 700 series DTC (Diagnostic Trouble Code) with a transmission, transfer case or other driveline components, check for a DTC under chassis and body systems, not just under “P” or powertrain/engine or emission control type codes. Module communications DTCs are “U” codes. These are most often found when looking for DTCs under chassis or body systems. Chassis related codes are labeled “C” and body system related codes are labeled “B” codes and these can cause drivetrain issues if they affect a sensor that is also used by the heating and air conditioning system.

Figure 1 TFT Circuit Wiring Diagram

When the control module (PCM or TCM) detects one of the following unusual conditions, then DTC P0710 sets.

• Unrealistically large change in transmission temperature
• Transmission temperature which remains constant for a period of time in which a measurable amount of change is expected and is a type C DTC

What are the common causes of code P0710 ?

• Faulty Transmission Fluid Temperature Sensor
• Transmission Fluid Temperature Sensor harness is open or shorted
• Transmission Fluid Temperature Sensor circuit poor electrical connection

What are the symptoms of code P0710 ?

• MIL (Malfunction Indicator Lamp [Check Engine & Service Engine Soon])lights on
• Possible automatic transmission shifting problems

Codes Related to P0710

• DTCs P0117, P0118 P0112, P0113, P0502 or P0503, and P1870.

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