transmission oil temp gauge and sensor

• 2024-01-26

The function of the automobile oil temperature gauge is to display the temperature of the engine oil, the higher the temperature, the lower the resistance. If the oil temperature is too high in abnormal situations, the oil temperature indicator light will be used to remind and warn.

1. The installation position and function of the transmission oil temperature sensor The transmission oil temperature sensor is installed on the valve plate in the oil pan of the automatic transmission. It is used to detect the temperature of hydraulic oil of automatic transmission, so as to perform shift control, oil pressure control and lock-up clutch control as an electronic control unit
 basis.

2. Structure and working principle of transmission oil temperature sensor Inside the transmission oil temperature sensor is a semiconductor thermistor with negative temperature coefficient. The higher the degree, the lower the resistance. The characteristic curve of its resistance changing with temperature is shown in the negative temperature coefficient thermistor in the coolant temperature sensor.resistance characteristics. The computer measures the temperature of the automatic transmission hydraulic fluid based on the change in its resistance.

3. Detection method of transmission oil temperature sensor
1 Measure the resistance value of the oil temperature sensor, remove the transmission oil temperature sensor, place the sensor in a beaker filled with water, and heat it in the beaker water, measure the resistance between the two terminals of the sensor at different temperatures. Standard value of sensor resistance Compare the measured resistance value with the specified value. If the resistance value differs greatly from the specified value, it should be replaced.

4. Symptoms that the transmission oil temperature sensor is broken The function of the transmission oil temperature sensor is to detect the temperature of the hydraulic oil of the automatic transmission, as the basis for the electronic control unit to perform shift control, oil pressure control and lock-up clutch control. The oil temperature sensor of the automatic transmission is installed on the control valve, which mainly controls the high temperature of the transmission. If the oil temperature sensor of the transmission is broken, the temperature of the transmission oil cannot be detected, thus it will not be able to provide the oil temperature signal to the transmission computer, which may cause the transmission shift shock. Torque converter when transmission oil temperature is high and dry 150°C. Immediately enter the lock-up condition, if the oil temperature of the transmission does not drop after 30s, the torque converter will release the lock-up condition, and the transmission will exit the overdrive gear.

The oil temperature sensor itself or the wiring harness is short-circuited, and the data flow will show that the transmission oil temperature is higher than 150°C, so the oil temperature sensor itself or the wiring harness is short-circuited.After the road, the torque converter does not enter the lock-up condition, the transmission does not have an overdrive gear, and the car does not have a high speed.