My air suspension is stuck in access height with the fault code (53) i believe it only says ecu fault.The fault code wont clear and none of the lights are illuminated on the control panel.Oh and there is no air suspension inactive message displayed.My guess is the ecu but wanted some input.

 

Probably the ECU fan ball bearing has worn completely out, causing too much humidity or heat to enter the ECU case and thus causing the computer to overheat. Maybe. I'm no expert but I had a similar prob with my '03 RR HSE, except mine hadnt worn out completely but I had it replaced anyway. If the fan goes out, obviously you can have BIG problems with your ECU....
Hope this helps at least a little bit.