The transmission oil temperature sensor YT315D is a key sensor installed in the automatic transmission (AT) system of the roller. Its main function is to monitor the temperature of the automatic transmission fluid (ATF) and convert this temperature information into an electrical signal to the electronic control unit (ECU) or transmission control module (TCM) of the vehicle. This information is essential for the efficient and safe operation of the automatic transmission. Here are some key aspects of the transmission oil temperature sensor:

Working principle

- Temperature perception: The sensor YT315D usually uses a negative temperature coefficient (NTC) thermistor element inside. The resistance value of this element decreases with increasing temperature and vice versa. When the transmission oil temperature changes, the resistance value of the thermistor changes.

- Electrical signal conversion: The ECU calculates the current oil temperature by monitoring the change in the resistance value in the sensor circuit. This electrical signal is usually an analog signal, representing a specific temperature value.

Main functions of Oil temperature sensor YT315D

1. Gear shift control: adjust the gear shift logic according to the oil temperature, such as avoiding shifting to a high gear at low temperatures to prevent gear shift shock; at high temperatures, downshift measures may be taken to reduce the oil temperature and protect the gearbox.

2. Oil pressure control: Oil temperature directly affects the viscosity of the oil, which in turn affects the oil pressure. The sensor signal helps the ECU adjust the oil pressure to ensure that the oil pressure is not too high at low temperatures to avoid shock; the oil pressure is sufficient at high temperatures to ensure lubrication.

3. Locking clutch control: There is a locking clutch in the automatic transmission to improve transmission efficiency. It is not enabled when the oil temperature is too low to avoid transmission shock; it may be unlocked when the oil temperature is too high to prevent overheating.

4. Protection mechanism: Too high or too low oil temperature will trigger protection measures, such as limiting the gearbox function to avoid serious damage.

Fault impact

- Abnormal gear shift: Faults in Oil temperature sensor YT315D may cause inaccurate gear shift timing, delayed gear shifting, gear skipping or inability to shift gears.

- Failure of oil temperature management: Failure to accurately monitor oil temperature may result in the oil temperature being too high without timely cooling measures, or failure to take appropriate preheating measures when the oil temperature is too low.

- Performance degradation: Long-term poor oil temperature control will accelerate the aging of the transmission oil, affect the lubrication effect, and reduce the service life of the transmission.

Regular inspection and replacement of the Oil temperature sensor YT315D are necessary maintenance measures to ensure the normal operation of the sensor, which will help improve the overall performance of the transmission and extend its service life. If a sensor failure is suspected, it can be checked by reading the fault code through a professional diagnostic tool or directly measuring the change in its resistance value.