System Operation: Notes

When the A/C switch, the AUTO switch, or the DEF switch is pressed, or when shifting mode position to D/F, the A/C auto amp. transmits the A/C switch signal and blower fan motor switch signal to the ECM, via CAN communication.

ECM judges whether the A/C compressor can be turned ON, based on each sensor status (refrigerant-pressure sensor signal, throttle angle, etc.). If the ECM judges that the A/C compressor can be turned ON, it sends A/C compressor request signal to the IPDM E/R, via CAN communication.

Upon receipt of A/C compressor request signal from the ECM, the IPDM E/R turns the A/C relay ON to operate the A/C compressor.

When sending A/C compressor request signal to the IPDM E/R via CAN communication line, the ECM simultaneously sends A/C compressor feedback signal to A/C auto amp. via CAN communication line.

The ECM sends A/C compressor feedback signal to A/C auto amp., then, uses input A/C compressor feedback signal to control air inlet.