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Control of A/C compressor

Control of A/C compressor

The A/C compressor engagement is controlled by functions in DICE and ECM. The following description covers what applies to functions in ECM.

The A/C compressor control function comprises two sub-functions


- logic function

- control function


Logic function



The logic function determines whether the A/C compressor should be turned off. This is done to enable turning off the A/C compressor under certain circumstances when the engine's maximum torque must be made available.

The A/C compressor will be turned off under the following conditions


- Coolant temperature higher than 123°C (253°F)

- Pedal sensor value greater than 95% and engine speed < 2500 rpm while driving in first gear

- Engine speed < 600 rpm


Control function

The control function governs the engagement and disengagement of the A/C relay after a command from the logic function.

After the power stage has amplified the signal, pin K30 will be grounded and the A/C relay will energize the A/C compressor electromagnetic clutch.