A/C Compressor Activation
Function
The A/C compressor is controlled as follows:
- Operation of the air conditioning button
- Transmission of the request via the Central Gateway Module (ZGM) to the digital engine module DME/DDE
- Setting of the operating mode ”Air conditioning on” by the DME/DDE
- Transmission of the status from the DME/DDE via the powertrain CAN to the ZGM
- Transmission of the request from the ZGM via the K-CAN to the air conditioning control unit
- Activation of the air conditioning compressor
The A/C compressor is switched off in precisely the same way.
This procedure ensures that at the time the air conditioning compressor is switched on, the engine has sufficient power reserves. Activation of the A/C compressor does not bring about a dip in engine speed.
Diagnosis
In the event of a fault, the entire signal path must be checked.