Battery Temperature Sensor: Description and Operation

The PCM uses the temperature of the battery area to control the charge rate. This temperature data, along with data from monitored line voltage, is used by the PCM to vary the battery charging rate. The system voltage is higher at cold temperatures and is gradually reduced as temperature around the battery increases.

The function of the battery temperature sensor (BTS) is to enable control of the generator output based upon ambient battery temperature. As battery temperature increases, the charging rate should decrease. As battery temperature decreases, the charging rate should increase. The sensor functions similar to the ECT sensor with one major difference, the ambient sensor does not have a dual temperature range program. The PCM maintains the optimal out- put of the generator by monitoring battery voltage and controlling battery voltage to a range of 13.5 - 14.7 volts based on battery temperature.

The battery temperature sensor is also used for OBD II diagnostics. Certain faults and OBD II monitors are either enabled or disabled depending upon the battery temperature sensor input (example: disable purge and EGR, enable LDP). Most OBD II monitors are disabled below 20 °F.