OBD2 codes.

Transmission Fluid Temperature Sensor Circuit Malfunction

The automatic gearbox has its own control unit (TCM), which decides when to shift using speed, temperature, pressure and selector position sensors. The gearbox oil temperature sensor lets the control unit adapt shifts and torque converter lock-up to the temperature. This code means a fault in its circuit.

What the car has detected

The gearbox oil temperature sensor signal is missing or invalid (open or short circuit; some makes use their own codes such as P0712 or P0713).

Without that reading the control unit uses back-up values: shifts may be harsh or late and the gearbox isn't protected against overheating. Get it checked soon and avoid heavy work such as towing.

Symptoms

• Engine or gearbox warning light on
• Harsh or late shifts, especially when cold
• Torque converter not locking up (higher revs on the motorway)
• Limp mode in some cases

Possible causes

• Failed temperature sensor
• Wiring or connector with a short or open circuit
• On some gearboxes the sensor is in the valve body or mechatronic unit
• Gearbox control unit fault (rare)

Checks for the garage

• Read the gearbox oil temperature with diagnostics and check it is plausible
• Check the sensor connector and wiring
• Measure the sensor's resistance against temperature, if accessible
• Check the gearbox oil level and condition

Next step

Have the gearbox oil temperature read with diagnostics and the sensor and its wiring checked.

Go to a garage: on many automatic gearboxes the sensor is inside the box and replacing it means draining the oil.

Original sources · Date indicated: 2026-10-12