Battery temperature sensor circuit

The battery temperature sensor installed on the battery current sensor detects battery temperature.

A thermistor is integrated into the battery temperature sensor, and the resistance in the battery temperature sensor changes according to the battery temperature.

The resistance of the thermistor in the battery temperature sensor decreases as the battery temperature increases. The resistance increases as the temperature decreases.

The battery temperature sensor is connected to the ecm. The ecm supplies 5 v from the thb terminal to the battery temperature sensor through resistor r.

The battery temperature sensor and resistor r are connected in series. This results in fluctuations in the voltage supplied from the thb terminal when the resistance changes according to the battery temperature.

The ecm determines the battery temperature according to fluctuations in voltage. When the battery temperature is high, the ecm determines to reduce the amount of current supplied from the generator in order to protect the battery.

Refer to dtc p1550 (see page es-262)

1. 1
   Inspect battery current sensor
2. 2
   Disconnect the b29 battery current sensor connector.
3. 3
   Measure the resistance.

Standard resistance

1. 1
   Check harness and connector (battery current sensor - ecm)
2. 2
   Disconnect the b29 battery current sensor connector.
3. 3
   Disconnect the b30 ecm connectors.
4. 4
   Measure the resistance of the wire harness side connectors.

Standard resistance (check for open)

Standard resistance (check for short)