Circuit Description

The automatic transmission fluid (ATF) temperature sensor converts the fluid temperature into a resistance value which is input into the engine control module (ECM). The ECM applies a voltage to the temperature sensor through the ECM connector C19 terminal 95. The sensor resistance changes with the transmission fluid temperature. As the temperature becomes higher, the sensor resistance decreases. One terminal of the sensor is grounded so that the sensor resistance decreases and the voltage goes down as the temperature becomes higher. The ECM calculates the fluid temperature based on the voltage signal.

These DTCs indicate an open or short in the ATF temperature sensor circuit. The ATF temperature sensor converts ATF temperature to an electrical resistance value. Based on the resistance, the ECM determines the ATF temperature, and the ECM detects an open or short in the ATF temperature circuit. If the resistance value of the ATF temperature is less than 79 Ohms or more than 156 Kohms, the ECM interprets this as a fault in the ATF sensor or wiring. The ECM will turn on the MIL and store the appropriate DTC.