○ Clean the unit and connectors 

○ Read the list of faults to identify failures 

○ Preventive replacement of all worn and fragile components

○ Full operational test on a test bench 

○ Fitting on the vehicle, identical to the genuine part including the calibration download process if required

○ The memory function can no longer be activated

○ The audio system is silent

○ A CD is stuck inside the player

○ The sound level is not gradual

○ The navigation no longer works

○ The SIM card or navigation CD

○ The speakers

○ The aerial cable