Trans Temp Sensor, No Rise After Start (Non-OBD II)

Name of Code:
164 (SA4) - Trans Temp Sensor No Rise After Start

When Monitored:
Continuously with the key on and engine running.

Set Condition:
This code will set if the transmission sump is less than 40°F and it does not rise more than 16°F after 10 minutes of run time. This code will also set if the vehicle temp (verified using battery temp and engine coolant temp) is below 100°F and the bans temp is above 260°F

Theory of Operation:
The Transmission Temperature Sensor is a positive temperature coefficient (PTC) thermistor type sensor. At cold temperatures the resistance is low and it rises with increased trans oil temperature. The sensor is provided with 5.5 volt supply from the PCM. The sensor supplies a signal to the PCM ranging from approximately 1.5 volts (cod) to 3.75 volts (hot). Note That when trans temp codes 74 (trans temp low) or 75 (trans temp high) are set, the PCM will use the engine coolant temperature as a default value for trans temp. Therefore, if one of these codes is set, the trans temp readings should not be used for diagnostic purposes. When the trans temp is below 32 degree F overdrive and TCC are disabled. When the trans temp is above 260 degree F overdrive is disabled and 3rd gear with TCC is used to cool the transmission.

Transmission effects:
When the transmission is using engine temperature as a default, transmission temperature is calculated using the following equation: (engine coolant temp x 0.4375)+ 87. If no engine coolant temp is available, 180 degrees F will be substituted. The MIL will not illuminate.

Possible Causes:
- Faulty Transmission Temperature Sensor
- Corroded, damaged, pushed out, miswired, or disconnected connector(s)
- Internal controller failure (PCM)