Recently i've been having some issues that i just can not seem to figure out.
I am driving a 2006 W221 S500.
At random i am getting some errors on the display and COMAND unit and also faults when using DAS to do a full test.
The problems do mainly seem to come up when reversing after driving for a while, but also randomly come up while driving.

The list of symptoms, which all come at exactly the same time:

• Air suspension becomes very stiff
• 'Tire pressure monitoring does not function' error message in main display
• 'Parking assistant does not function' error message in main display
• 'ESP does not function' error message in main display
• 'Distronic plus / Speedtronic not available' message in main display
• 'Steering angle sensor is not initialised' message in COMAND display when activating reverse while the issues are present

The fault codes that i get when doing a full test on all modules with DAS(these faults all come at the same time together with the symptoms above):

• ETC - Electronic transmission control
  061B Component Y3/8n4 (Fully integrated transmission control (VGS) control unit) is defective.
• DTR - Distronic
  6231 One or more messages sent from control unit N47-5 (ESP control unit) via the CAN bus is implausible. ( Steering angle , Rotational speed )
• SGR - Radar sensors control unit
  7451 CAN signal 'Steering angle' from control unit N80 (Steering column module) is implausible.
  7409 Chassis CAN bus : No CAN message was received from control unit N47-5 (ESP control unit).
  7306 Vehicle dynamics CAN bus : CAN communication is faulty.
• ABR - Adaptive Brake
  5938 Check component N49 (Steering angle sensor).
• XALWA-L - Xenon headlamp, left
  5017 CAN signal 'Steering angle' from control unit SCM [MRM] is implausible.
• BNS - Vehicle power supply control module
  9014 The consumer shutoff is active.
• SCM [MRM] - Steering column module
  9334 Component N49 (Steering angle sensor) is defective.
  9352 Steering angle sensor speed too high

I was already suggested to check the passenger footwell for moisture as there is a module there where a lot of CAN wiring comes together, but this was dry and all connectors were nice and clean.
Besides this i can't really find anyone with the same issues, and i do suspect something with CAN signals and/or wiring as i personally doubt all these modules to break at the same time and also repair themselves at the same time.

If anyone has any idea where i could start from here i would highly appreciate it, i am completely out of idea's.
I have been through many pages of posts within the W221 section and also did a lot of searching but can not find anyone with anything like this.
Besides this the car has no issues. It drives, shifts and steers great, even when the faults are present, except for the very stiff suspension at that moment and some features not being available.

If i missed any information that might be relevant please ask, i can always try to gather more.