What it means
The transmission control module monitors the circuit for transmission fluid temperature sensor C. This code sets when the circuit signal is outside the expected electrical range; the title does not specify the type of circuit fault.
At a glance
- Usually lights the check-engine light
How it works
Transmission fluid temperature sensor C measures fluid temperature at its sensing point and sends an electrical signal to the transmission control module. P274A sets when the sensor C circuit falls outside its expected electrical range; the code alone does not identify whether the signal is too high or too low.
Common causes
Most likely first.
- Open sensor element or broken sensor wire
- Corroded sensor connector
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and compare sensor C's reported temperature with other available transmission temperature readings and ambient conditions.
- Inspect sensor C's connector and wiring for an open, corrosion, loose terminals, or heat damage.
- Check whether the reported temperature is implausible or fixed while the transmission warms or cools.
- Test the sensor C signal, reference, and ground circuits using the wiring diagram and manufacturer's specifications.
- If the wiring tests correctly, test sensor C itself and inspect that it is seated in the fluid path.
Common fixes
- Reconnect sensor C and repair corroded connector terminals.
- Repair an open or damaged sensor C wire.
- Replace the faulty transmission fluid temperature sensor C.
- Correct sensor C's seating if it is not positioned in the fluid path.
Can I keep driving?
Keep trips short and gentle until the fault is diagnosed; incorrect temperature data can affect shift control and may lead to limp mode or slipping. Stop if the transmission slips, shudders severely, or loses drive.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.