This bulletin provides information relating to vehicles equipped with a battery sensor. KIA emphasizes the caution not to install an additional ground cable to the battery on any vehicles equipped with a battery sensor. Installing an additional ground cable to a battery (-) terminal may cause the battery sensor to incorrectly recognize the battery state (charged/discharged) and temperature information. Advise customers not to install an additional battery ground cable. Emphasize the fact that a vehicle repair caused by the additional battery ground will not be covered under warranty.
The battery sensor, which is embedded on the battery (-) terminal transmits battery voltage and temperature information to the ECM. The ECM controls alternator voltage output necessary for the various vehicle electric units by duty cycle based on signals received from the battery sensor. Also, on some vehicles with the ISG (Idle Stop & G0) function, the idle stop and auto start are determined by the battery state of charge (SOC) and state of health (SOH) information received from the battery sensor.
If an additional ground cable is installed on the battery (-) terminal, the battery sensor may incorrectly register that the battery is in a discharged state, despite a normal battery condition. This may cause the battery sensor to transmit incorrect information to the ECM, alternator voltage output and ISG control, resulting in improper operation of various systems and components, as well as possible setting DTCs as listed below:
Battery sensor fault as detected by the ECM. Cause: battery sensor is abnormal. MIL off. Cause: poor connection or open/short.
LIN communication error. No MIL illumination. Open or short in LIN communication line.
Alternator control circuit. Open or short in harness. No MIL.
AMS voltage rationality. There is a wide voltage difference between battery sensor and actual value. No MIL.
AMS charging system voltage. Battery voltage at the power supply terminal of the ECM. Voltage from the battery sensor is greater than 3V. No MIL.
AMS no battery charge. State of charge (SOC) calibration. No MIL.