Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Battery Current Sensor (With Battery Temperature Sensor)
FUNCTIONS WITHIN THE SYSTEM
The ECM judges the battery load state based on the battery current sensor and battery temperature sensor, and controls the amount of alternator power generation. As a result, it is possible to reduce the engine load.
INDIVIDUAL FUNCTION WITHIN THE SYSTEM
Battery Current Sensor
The battery current sensor detects the battery charge/discharge current and transmits a signal to the ECM.
Battery Temperature Sensor
The battery temperature sensor is integrated in battery current sensor. The sensor measures temperature around the battery.
INDIVIDUAL OPERATION
Battery Current Sensor
In this vehicle, the battery current sensor that is installed on the negative cable of the battery is used to measure the battery input/output current and perform various controls. If electrical equipment, ground wire, or other items are directly connected to the battery terminals, this may result in control errors because battery current input/output other than that measured by the battery current sensor is taking place. In the worst case, issues such as a dead battery may occur. Never directly connect electrical equipment, ground wire, or other items to the battery terminals.
Battery Temperature Sensor
The battery temperature sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.
| Temperature [°C (°F)] | Voltage* (V) | Resistance (kΩ) |
|---|---|---|
| 25 (77) | 3.333 | 1.9 - 2.1 |
| 90 (194) | 0.969 | 0.222 - 0.258 |
*: These data are reference values and are measured between ECM terminals.
COMPONENT LOCATION
The battery current sensor is installed on the battery negative cable.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.