P0713
PowertrainTransmission Fluid Temperature Sensor Circuit High Input
Usually a small job, not a gearbox rebuild, so don't panic when you see this one. The transmission control side is reading a higher voltage than it should from the fluid temperature sensor, which points to an open circuit, a dead sensor, or broken wiring rather than the fluid actually being too hot. High voltage on this circuit normally means the signal isn't getting back, so the module assumes the worst and often drops the box into limp mode to protect itself. Most of the time the fix is a connector, a length of wire, or the sensor itself, all of which are at the cheaper end of gearbox faults.
ⓘ Information only. This page provides general educational information about fault code P0713. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0713 mean?
P0713 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Transmission Fluid Temperature Sensor Circuit High Input.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light or a dedicated transmission/gearbox warning lamp on the dash
- • Harsh, delayed or hunting gear changes, sometimes it'll feel like it can't decide which gear it wants
- • Box drops into limp mode, often stuck in third with no kickdown
- • An over-temperature warning showing even on a cold start when the fluid is stone cold, which is a giveaway for this fault
- • Slightly worse fuel economy because the shift map has gone defensive
- • Occasional whine or clunk under load if the box is shifting roughly
Possible causes
Causes commonly associated with P0713, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Failed transmission fluid temperature sensor, the single most common cause. They're a thermistor and tend to read open or sky-high as they die
- 2. Broken or chafed wiring in the sensor harness causing an open circuit, common where the loom passes near hot exhaust or sharp brackets
- 3. Corroded or loose connector at the sensor or at the control module, water and gearbox heat are hard on those pins
- 4. Sensor circuit shorted to a voltage source, less common but it will pull the reading high
- 5. Low or badly contaminated fluid affecting how the sensor sits and reads, worth ruling out early on a neglected box
- 6. On the rare end, a faulty TCM or PCM, but only chase this once the cheap stuff is properly tested
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Read live data and watch the actual fluid temperature value. If it's showing something daft like -40C or a maxed-out figure on a warm engine, that confirms the signal is lost rather than the fluid being hot
- 2. Get the sensor connector unplugged and inspect it properly. Look for green corrosion, spread pins, and any sign the loom has been rubbing or melting against the exhaust
- 3. Check the fluid level and condition while you're under there. Burnt, dark or low fluid can drag readings about and needs sorting first anyway
- 4. Probe the sensor circuit with the ignition on and engine off. A reading sat up near the 5V reference points to an open in the sensor or its wiring
- 5. Measure the sensor's resistance with a multimeter and compare it to the temperature value in the service data. A reading that's wildly out or open confirms the sensor
- 6. If the sensor and wiring both check out clean, only then start looking at the control module
Common questions about P0713
How do I know if it's the sensor or the wiring on my car? +
Live data settles it most of the time. Plug in a scanner, get the engine warm, and look at the fluid temp figure. If it reads an impossible low number or pegs at the top while everything else is normal, the signal is missing, so it's either the sensor or an open in the circuit. Wiggle the harness and connector with live data running. If the value jumps about as you move it, you've found a wiring or connector fault. If it stays dead with a good clean connector, the sensor itself is the likely culprit. On boxes where the sensor lives inside the sump as part of the internal loom, a sensor swap and a wiring fault end up being the same job anyway.
Can I sort this myself or is it a garage job? +
If your gearbox has an external sensor with an accessible connector, swapping it and cleaning up the wiring is a fair DIY job. Budget roughly £20 to £70 for the sensor plus the right fluid to top off whatever you lose. Where it gets awkward is the boxes that have the sensor on the internal valve body or built into the harness inside the sump, because then you're draining fluid, dropping the pan, and refilling to the correct level, which on a lot of modern autos means a proper fill-and-check procedure rather than a simple dipstick top-up. If you're not set up to get the fluid level spot on, hand that part to a garage. Getting the level wrong does more harm than the original fault.
Will clearing the code just make it go away? +
Only briefly. If the wire is broken or the sensor is dead, the module will read that high voltage again within a drive cycle or two and relight the lamp, usually dropping it back into limp mode. Clearing it is only useful as a test after you've actually repaired the cause, to confirm it stays off. Driving around with it cleared and ignored isn't free either, because the box can't see its real temperature and may keep running defensive shift patterns that put extra heat through the fluid over time.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →