Porsche Climate Control

[gkmaia]

My climate control has gone kaputs...

The control is based on a C515C microcontroller and interfaces with the CANBUS with a TJA1054. According to the datasheet failure scenarios the 1054 seems to be working properly.

The display is driven by a PCF8576. As you can see in the video bellow the unit is able to to drive the display and the car's actuators. However I can't control the temperature.

And by looking at the cars wiring is possible to see that all that works is connected directly to the unit, while temperature sensors info has to come from the canbus.

Is it an indication that there is no hardware issue with the unit? Most likely lost the capacity to communicate with the canbus?



https://www.nxp.com/docs/en/data-sheet/PCF8576.pdf
https://pdf.datasheetcatalog.com/datasheet/philips/TJA1054T.pdf
https://www.jakelectronics.com/pdf/datasheets/infineon-safc515c8em-datasheets-1499?product=infineontechnologies-safc515c8em-13112211

[kripton2035]

isn't it simply that you're out of refrigering gaz ?

[gkmaia]

isn't it simply that you're out of refrigering gaz ?

Probably not, because I have a canbus diagnostics tool and the car has no issue. It would show in the can bus if the refrigerant pressure was off.

[Haenk]

Probably not, because I have a canbus diagnostics tool and the car has no issue. It would show in the can bus if the refrigerant pressure was off.

So you can read the actual outside temperature via OBD?
And did you scan for further errors via OBD, the pressure sensor should bring up a reading as well?
"No issue" is really of no meaning, the temperature sensor might read -50oC - which will make the aircon stop but will not create a fault.

From the behaviour I would expect an error inside the airconditioning system, not in the frontend unit.

[gkmaia]

The OBD I have is a Porsche specific one so it access all areas of the car. And yes I can read at least 20 parameters within the AC system. It is very comprehensive and all parameters related to AC seemed to be within spec. But, will review the parameter to make sure they are in spec and not missing anything.

Also, if I scan the car without the AC module connected it accuses the module is missing and it could only know that through the canbus as you can see in the diagram attached there are no ID lines. This supports your theory that the unit is working, communicating with the ECU and the problem is somewhere else.

[EHT]

What about power supply and ground lines in some places? Have you also asked in rennlist to see if there is some common problem on that model, perhaps something with the wiring looms or water ingress