DTC P0516-769: Battery Temperature Sensor Circuit Low; DTC P0517-770: Battery Temperature Sensor Circuit High: Description

The auxiliary battery temperature sensor detects the auxiliary battery temperature. The resistance of the thermistor built into the auxiliary battery temperature sensor changes in accordance with changes in the auxiliary battery temperature. The lower the auxiliary battery temperature, the higher the thermistor resistance. Conversely, the higher the temperature, the lower the resistance. The auxiliary battery temperature sensor is connected to the hybrid vehicle control ECU. A voltage of 5 V is supplied to the auxiliary battery temperature sensor from the THB terminal of the hybrid vehicle control ECU through its internal resistor. This means that the resistor and the auxiliary battery temperature sensor are connected in series. The voltage at the THB terminal and the resistance value change in accordance with changes in the auxiliary battery temperature. Based on this signal, the hybrid vehicle control ECU reduces the charging current when the auxiliary battery temperature is high to protect the auxiliary battery.

Fig 1: Identifying Resistance To Temperature Graph
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DTC No.	INF Code	DTC Detection Condition	Trouble Area
P0516	769	Malfunction in the auxiliary battery temperature sensor circuit (short to GND)	Battery (Battery temperature sensor) Wire harness or connector Hybrid vehicle control ECU
P0517	770	Malfunction in the auxiliary battery temperature sensor circuit (open or short to +B)