P0710–P2740 Transmission Fluid Temperature Sensor A Circuit
The ECU has logged a fault on P0710. The definition below is the exact wording the standard uses for this code.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P0710 | Transmission Fluid Temperature Sensor A Circuit | Investigate soon |
P2740 | Transmission Fluid Temperature Sensor B Circuit | Investigate soon |
The definition
P0710: Transmission Fluid Temperature Sensor A Circuit.
P0710 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
What actually causes this on a VAG
Your automatic gearbox measures the temperature of its own oil and uses that reading constantly: to decide how firmly to shift, when it is safe to lock the torque converter, and when to protect itself in traffic or when towing. P0710 means the control unit is not getting a believable signal from that sensor at all. On most VAG automatics and DSG boxes this is not a bolt-on part you can reach - it lives inside, as part of the internal wiring harness or the mechatronic unit, with its wires leaving through a sealed plug in the casing. Note that the official description says sensor 'A': some of these gearboxes carry more than one temperature sensor, so make sure any quote is for the right one. The car will often feel firmer or lazier than usual and may hold a safe gear, because the control unit will not risk normal shift behaviour without a temperature reference.
Most likely causes, in order
- Connector or loom fault at the gearbox. The external plug takes heat, spray and salt, and can also fill with oil that has crept along the inside of the wires. Corroded pins, a plug not properly latched after a service, or a chafed wire near the exhaust are all common and all repairable. Unplug it and look for corrosion and oil film before anything else, and watch the live temperature value in a scan tool while flexing the loom.
- Recent work left something disturbed. If this code appeared shortly after a gearbox service, a mechatronic repair, or a starter or subframe job, suspect the plug or a trapped wire before anything internal. Ask what was disconnected and have that checked first. This is the cheapest possible outcome and it is a genuinely frequent one.
- Sensor or internal harness failure inside the gearbox. The sensor itself, or the internal harness carrying its signal, can fail. On most of these boxes reaching either means opening the gearbox or replacing a mechatronic assembly, so this must be proved by measuring at the external gearbox connector, not assumed because the code mentions a sensor. Insist on seeing that measurement before agreeing to internal work.
Worth knowing: This matters more than most sensor codes, for a reason that is easy to miss. The oil level on VAG automatics and DSG boxes has to be set with the fluid inside a specified temperature window, and that window is judged from this very sensor. With no valid reading, nobody can set the level correctly. So fix this fault before any fluid service, not after - and be sceptical of a gearbox that was 'serviced' while this code was already stored, because the level may well have been set wrong, which does far more damage than the original fault.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P0710 mean?
P0710 means Transmission Fluid Temperature Sensor A Circuit. It is logged when the ECU sees this circuit outside its expected operating window.
Can I drive with P0710?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.