U1520 is a 'Lost communication' code related to the body control module here in the U.S.
It is somewhat generic so my definition may apply to your car.........what country is the car being operated in?
If it was here, my first thought would be to exchange the negative battery cable......a component that was poorly manufactured with a failure rate high enough for G.M. to extend the warranty on.
Have you had any other electrical issues such as the radio going blank, the clock resetting, or all the instrument needles bouncing around?
If anything like that has occured I would exchange the cable before doing any further diagnostics.
Rob
It is somewhat generic so my definition may apply to your car.........what country is the car being operated in?
If it was here, my first thought would be to exchange the negative battery cable......a component that was poorly manufactured with a failure rate high enough for G.M. to extend the warranty on.
Have you had any other electrical issues such as the radio going blank, the clock resetting, or all the instrument needles bouncing around?
If anything like that has occured I would exchange the cable before doing any further diagnostics.
Rob