RAM 1500 Van V8-5.9L VIN Z LDC (2001)
Battery Temperature Sensor: Description and Operation
The Battery Temperature Sensor (BTS) is attached to the battery tray located under the battery.
The BTS is used to determine the battery temperature and control battery charging rate. This temperature data, along with data from monitored line
voltage, is used by the PCM to vary the battery charging rate. System voltage will be higher at colder temperatures and is gradually reduced at warmer
temperatures.
The PCM sends 5 volts to the sensor and is grounded through the sensor return line. As temperature increases, resistance in the sensor decreases and the
detection voltage at the PCM increases.
The BTS is also used for OBD II diagnostics. Certain faults and OBD II monitors are either enabled or disabled, depending upon BTS input (for
example, disable purge and enable Leak Detection Pump (LDP) and 02 sensor heater tests). Most OBD II monitors are disabled below 20 degrees F.