Sub Battery Current Sensor
WARNING: This page is about a different car, the 2018 Infiniti Q50. However, it is still accessible from the selected car via links, so may be relevant.
The sub battery current sensor is installed to the negative cable of the sub battery. The battery current sensor detects the sub battery charge/discharge current and transmits a signal to EMCM. EMCM judges the sub battery load based on the signal.
CAUTION:
Never connect the electrical component or the ground wire directly to the battery terminal. The connection causes the malfunction of the power voltage variable control, and may cause the battery to discharge.