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Bus message
|
Unit
|
Transmitter
|
User
|
Description
|
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A/C compressor request
|
On/Off
|
ACC
|
ECM
|
The ACC requests A/C compressor engagement if the ambient temperature exceeds 0°C and A/C OFF is not selected. The ECM activates the compressor if the pressure is sufficient and the engine is running.
|
|
A/C compressor request
|
On/Off
|
BCM
|
ECM
|
The MCC is not connected to the bus. The A/C command is sent via a separate lead to the BCM which requests A/C compressor engagement. The ECM activates the compressor if the pressure is sufficient and the engine is running.
|
|
A/C idle speed increase request
|
On/Off
|
BCM
|
ECM
|
The purpose of the function is to improve cooling properties when the engine is idling and the ambient temperature is high. At temperatures higher than 28°C when the A/C is active, the BCM will request an idle speed increase from the engine management system.
|
|
A/C compressor clutch active
|
On/Off
|
ECM
|
ACC, BCM
|
If the A/C compressor is not activated, recirculation will be selected in order to improve cooling properties. Recirculation is prevented if there is an A/C function fault. The BCM uses the information to increase the idle speed when the compressor is active and the ambient temperature is high.
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