IHKA and MHD tune


Sep 1, 2021
Hi everyone. Any expert on here know about the E60 IHKA(High) control logic on the N54 AC Compressor solenoid ( 7SEU17C ) ? I am having issue with the A/C system as soon as the engine speed above the idle speed. the A/C system is getting 15-17bar high side ( 32-40 PSI low side) and the evaporator getting 5c-0.5c as soon as the AC button pressed at idle ( station), A/C button have been cycle on and off to test for the functionality, as soon as the button press, it is confirmed that the refrigeration capacity value increase to 80-90% ( I believe that is the value of the Solenoid PWM) Per ISTA+ read out, however as soon as I rev the engine at idle or as soon as I take off from standstill, the high pressure side come back down to 8-10 bar even the refrigeration capacity value still show 90-94% ( Note, as soon as the A/C button not light up, the value is ZERO) , I believe that value not the system total output, it is only showing the command of the button, I believe the DME is limiting the IHKA output . I do have a radiator blind shutter code , however the car never had one, I had a custom tune from a tuner and ever since that code stay on, so my question is , anyone know what is the control logic and what is the CAN bus bit I can monitor to see what is limiting the IHKA output to the compressor? Anyone know the bit in the tune file address i can turn off the radiator shutter code? or deactivate it since I don't have one?