Toyota Rav4 cd multichanger??

I m sorry but I don't thing I have the knowledge to solve this problem

call the dealer with the VIN

The code is located with the original paperwork/manual provided with the vehicle. If you do not have this, you will need to take the car to a Toyota dealership and provide them with the radio serial number and the VIN.

yes check the wiring

Have blown fuses or fusible links or melted
bars under fuse & distribution box-- depending
on what the car has

put the cd player off and on repetaedly until the err-3 disappears.

You've got a blown fuse. Check your fuse box.

Replace the CD player. To pull the plastic baffle off the dashboard: Adjust the heating vents so they point downwards. Grab the plastic bar between the heating vents and the stereo. Pull. Remove the screws from the front of the mounting brackets. Pull out the crappy stereo. Unplug the antenna and the wiring harnesses. Transfer the mounting brackets to your new stereo. Cut off the big wiring harness (unless you're lucky enough to have a replacement stereo that accepts the same kind). Connect the wires to the wires on your new stereo's harness. For more info: check the website: http://tomclegg.net/toyotastereo

If I unplug all the wires from the CD player won't the security system lock up my stereo system? Which means that I have to go to a dealer to get the code from them.

Send me the code for the radio, I have all of the unlock codes.