P275A: Transmission Fluid Temperature Sensor D Circuit
What to do
Check the transmission fluid level and condition before anything else — it is the working fluid of the whole system, and low or degraded fluid causes faults that look electrical. The car will usually still drive. If gear changes become harsh, if it slips, or if you smell burning, stop driving and have it recovered.
What this code means
Transmission fluid temperature sensor D has a circuit fault.
Transmission fluid temperature is not a comfort reading. The module shifts differently depending on it.
Cold fluid is thick and grips differently, so a cold transmission upshifts later, may lock the torque converter not at all, and applies clutches with more pressure to compensate. Hot fluid is thin, so pressures rise and the module may hold lower gears to keep the pump speed up. Losing the reading means every one of those adjustments is made on a guess.
A defaulted sensor usually reads a safe middle value, which is worse than it sounds: the transmission then behaves as though warm when it is freezing, and as though warm when it is overheating. The protective strategies that would have limited damage never trigger.
A circuit fault names the electrical path. Most of these sensors are inside the transmission, often built into the valve body or the internal harness — so replacement means dropping the pan, and the external connector deserves checking first because it is free.
More than one temperature sensor is normal on a modern transmission — sump, cooler outlet and clutch pack can all be measured, because the difference between them is what says whether the cooler is working. Sensor D is one of that set, and the vehicle's documentation says which position it occupies.
Transmission fluid is the first thing to check and the thing most often skipped.
It is not a lubricant that also happens to move things — it is the working fluid of a hydraulic machine. It carries the pressure that applies every clutch, it carries the heat away, it lubricates, and it is the friction surface itself: the additive package is tuned so clutches grip smoothly rather than snatching.
So fluid that is low, old, burnt or of the wrong specification changes how the transmission behaves, and it does so before any part has failed. Burnt fluid smells burnt and looks dark; healthy fluid is translucent. Checking it costs nothing and rules out a great deal.
"Filled for life" is a claim about the warranty, not the transmission. Many sealed units have no dipstick and a manufacturer schedule that never changes the fluid, and they still wear out faster on original fluid than on serviced fluid.
Likely causes
Start here
- Faulty transmission fluid temperature sensor · specialist
- Corroded or loose connector · specialist
- Damaged wiring harness · specialist
Less common
- Open circuit in solenoid wiring · specialist
Rare
- Faulty transmission control module · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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