I need to replace my cd changer with a second hand unit. Does it need recomputing?

sounds like the problem is that the head unit does not have the version coding set to show you have a cd changer installed in the vehicle. The second possibility is that the fiber optic ring in down which could give the same result. First you have to restart the fiber optic ring and then you have to check the version coding; You need to hook up a mercedes sds to the vehicle

Try putting your radio code back into the system it should be written in the hand book if you don't remember it.

I dont remember if that year had a theft lock system or not, but I am looking into it. disconnect the negative battery cable for ten minutes and that should get you back to where you can enter the unlock code again and use the radio.

With the low current draw that a cd unit uses It would take some hours to affect a good battery. Remove the fuse for the cd unit and have a battery shop check the battery for a bad cell ( Load test on the battery). Pull the cd player and have a tecki look at it as I feel you have 2 faults not connected.

Try pulling the fuse for the cd changer with the ignition on, and then plug it back in. If you are lucky you might reset the unit, otherwise the changer will likely need removed sent in for repair or replacement.

Unfortunately 90% of the time when you get error codes from the CD player/changer it means that there is a mechanical failure in the CD player/changer unit itself and it usually requires CD player/changer rebuild or replacement...
First make sure you have entered the correct anti-theft code. If battery power has been disconnected recently than the stereo display will read CODE if the incorrect anti-theft code is entered the display will read ERR1 thru ERR3. If this is the case you'll have to get the correct anti-theft code. Note; If you enter the incorrect code three times the stereo locks up. Disconnect the battery for more than 30 seconds and then retry.
FYI;Never use adhesive labels or protective disc covers on recordable CD's. Recordable CD's are actually thicker than pre-recorded CD's. Automotive players and changers use rollers to draw the disc into the unit. The added thickness of an adhesive label or protective disc cover may cause the disc to jam. Also CD players and changers are exposed to high temperatures inside the vehicle. High temp will cause the labels adhesive to soften which may cause the labels edges to curl or cause it to bubble. Either one may cause the disc to jam. If the player can not be disassembled and have the discs removed successfully than it will have to be replaced. -hope this helps.

Unfortunately 90% of the time when you get error codes from the CD player/changer it means that there is a mechanical failure in the CD player/changer unit itself and it usually requires CD player/changer rebuild or replacement...
First make sure you have entered the correct anti-theft code. If battery power has been disconnected recently than the stereo display will read CODE if the incorrect anti-theft code is entered the display will read ERR1 thru ERR3. If this is the case you'll have to get the correct anti-theft code. Note; If you enter the incorrect code three times the stereo locks up. Disconnect the battery for more than 30 seconds and then retry.
FYI;Never use adhesive labels or protective disc covers on recordable CD's. Recordable CD's are actually thicker than pre-recorded CD's. Automotive players and changers use rollers to draw the disc into the unit. The added thickness of an adhesive label or protective disc cover may cause the disc to jam. Also CD players and changers are exposed to high temperatures inside the vehicle. High temp will cause the labels adhesive to soften which may cause the labels edges to curl or cause it to bubble. Either one may cause the disc to jam and cause the player to display error codes E-01 thru E-07. If the player can not be disassembled and have the discs removed successfully than it will have to be replaced. -hope this helps.

CD player is not working. Motor will not unload or load discs. It will play CDs fine but cannot change them. Unit will need to be repaired by an audio specialoist or replaced.

Most of the time the cd changer will need to be replaced. Your only chance is to do a power reset to the cd changer. pull the fuse for 15 seconds, re-insert and see if the changer reboots correctly. The fuse chart is behind the triangular panel on the left side of the drivers side dash panel

this happens when the cd changer is going bad it is posible that the radio will play again if not the cd changer needs to be remove and the fiber optic cable loop needs to be plug back with out the cd changer

you can have the cd changer repair or go here to find a new one

http://www.oemautosound.com/c-162-mercedes-products.aspx