Communication between air conditioner and injection computer
The injection ECU authorizes the compressor to turn on based on the power the compressor draws and the refrigerant pressure in the circuit.
The information used for the air conditioning system is transmitted over the multiplex network:
- pin A 3 kakal CAN L multiplex network (CECBS);
- pin A A4 CAN channel H of the multiplex network (CECBS).
When the air conditioner switch is pressed, the air conditioner control panel requests permission to turn on the compressor. The injection ECU decides whether or not to turn on the compressor, controls the engine cooling fan and sets the appropriate fast idle speed, which is 896 min-1 for F4P engine and 848 min-1 for the K4M engine.
Attention! The refrigerant pressure and power input are never 0, whether the compressor is on or off.
A/C Compressor Activation Strategy
Note. In some engine operating modes, the injection computer prohibits the activation of the air conditioning compressor.
Engine start strategy
The operation of the air conditioning compressor is prohibited after starting the engine for 10 seconds.
Strategy for achieving maximum performance within a 5 second time delay.
Start conditions
Throttle valve fully open.
Engine speed below 3800 min-1.
2nd or higher gear engaged.
Termination conditions
Throttle valve not fully open.
Or after a time delay of 5 s.
Or at crankshaft speed.
Engine overspeed protection strategy.
The compressor turns off if the engine speed is above 6016 min-1 for F4P engine and 6500 min-1 for the K4M engine.
Overheat protection strategy
The compressor does not turn on if the coolant temperature is above 115°C for the F4P engine and 119°C for the K4M engine at high speeds and heavy engine load.