Security code does not work

I recently purchased a '91 560 SEC. I changed the battery and went to enter the code provided by MB Canada and it does not work! The screen on the radio just flashes "CODE". If I enter it in more than once it locks me out again with "WAIT". Can anyone explain the proper procedure for entering the code and what to do if the code ultimately does not work?

[jsmith]

it's a four digit code. sometimes they give you a five digit number with a leading zero which you can disregard but it's as simple as punching up the numbers when it asks for the code...

[David C Klasse]

After you enter the code, (which I guess could be 4 digits, but mine is 5 digits), you must press the SC button. I believe you have it on your car (just a different location that on mine). I had the same problem; I finally called the dealer and they told me to enter the code and then press SC. But you must first wait until the radio flashes CODE again, you can't do it while it says WAIT.
Good luck!

Thank you for the advice.

To answer a few questions: I was given a four digit code. I tried entering the code and pressing the SC button... Once again, "CODE" still appears on the radio. Do this more than once and... "WAIT" comes up for 1 to several hours until it resets again to "CODE".

I am still hoping that a simple (lower cost) solution exists out there.

Thank you to all for your help thus far

[carman850]

I bought my 92 400E from Toronto, when I picked up my car from dealer, I saw them swapping Radios from one car to another, so it's likely that your stereo is no longer the original one.

I guess MB dealer should be able to tell you the actual code by knowing the serial number of the stereo itself.

Good luck.

As it turns out the dealer had switched out the radio. The code on file with MB Canada was for the previous radio. After pulling the radio and obtaining the serial no..... calling MB Canada and obtaining the new code... well it worked BUT. The radio seems to have static/humming noise from time to time and the sound rises and falls on its own? I have not had the time to work on it lately. I am not sure if the speakers or the unit or both are at fault? If anyone has any suggestions I would very much appreciate it.

I am also considering changing out this stereo for CD player/stereo. Does anyone have any suggestions as to a make that might work out better for this car? Is there anything that I should consider before undertaking this project (I will check the archives)?

All of your previous suggestions were very helpful and allowed me to zero in on the solution quicker.

Thanks to all!