Transmission Temperature Sensor
AUTOMATIC TRANSMISSION - 42RLETRANSMISSION TEMPERATURE SENSOR
Description
Fig. 257 Transmission Temperature Sensor:
The transmission temperature sensor (2) (Fig. 257) is located in the transmission range sensor (1) and communicates transmission sump temperature to the TCM.
OPERATION
The transmission range sensor (TRS) has an integrated thermistor that the TCM uses to monitor the transmission's sump temperature. Since fluid temperature can affect transmission shift quality and convertor lock up, the TCM requires this information to determine which shift schedule to operate inch The TCM also monitors this temperature data so it can energize the vehicle cooling fan(s) when a transmission overheat condition exists. If the thermistor circuit fails, the TCM will revert to calculated oil temperature usage.
CALCULATED TEMPERATURE
A failure in the temperature sensor or circuit will result in calculated temperature being substituted for actual temperature. Calculated temperature is a predicted fluid temperature which is calculated from a combination of inputs:
- Battery (ambient) temperature
- Engine coolant temperature
- In-gear run time since start-up