Function Explanation (DTC Detection Outline)
- With the DC-DC converter (i-ELOOP) function, the PCM performs malfunction determination, and verification of vehicle malfunctions/safety assurance is performed.
- The DC-DC converter (i-ELOOP) is equipped with a voltage lowering function which supplies power to the 12 V line from the 25 V line. If this function does not operate, it may not be possible to supply power to the vehicle's electrical devices. In this diagnostic, the system detects whether the DC-DC converter (i-ELOOP) can respond to the command voltage from the PCM, or it detects a malfunction in the voltage lowering circuit based on the on-board diagnostic of the DC-DC converter (i-ELOOP).
- The DC-DC converter (i-ELOOP) is equipped with a discharge circuit which discharges a certain amount of capacitor (i-ELOOP) voltage when the ignition is switched off. If this function does not operate, the capacitor (i-ELOOP) may deteriorate. In this diagnostic, a discharge circuit malfunction condition is detected in the DC-DC converter (i-ELOOP), and a malfunction is determined by the PCM.
- The DC-DC converter (i-ELOOP) is equipped with a bypass circuit which supplies voltage generated by the generator to the 12 V line. If this function does not operate, a power supply shortage may occur. In this diagnostic, a bypass circuit malfunction condition is detected in the DC-DC converter (i-ELOOP), and a malfunction is determined by the PCM. In addition, a malfunction is determined by the PCM from a mismatch with the response signal of the DC-DC converter (i-ELOOP) in relation to the bypass relay drive command signal from the PCM.
- The DC-DC converter (i-ELOOP) monitors the input/output voltage and the output current, and the PCM performs charge/discharge control of the generator based on each of the signals to assure the vehicle's power supply. If the output current of the DC-DC converter (i-ELOOP) exceeds the assurance value of the internal circuit, or each input/output value indicates an abnormal value, normal supply of electricity may not be possible. In this diagnostic, each input/output terminal of the DC-DC converter (i-ELOOP) is detected as an abnormal value/exceeding assurance value, and a malfunction is determined by the PCM.