radio flashes "EEEE" instead of "CODE"

[foxmo]

I have a 1991 volvo 240 DL and when the mechanic recently replaced my
water pump he had to disconnect the battery, etc. etc. etc. And as you may have guessed the radio showed "code" when everything was hooked by up...unfortunately the manual with the code is nowhere to be found...so when I called the volvo dealer he gave me a code matching
the vin number...however, after putting that code in what resulted was the
"CODE" letters were replaced by "EEEE" but no audible sound and no action....I then tried to get the "CODE" on the radio face plate to reappear by disconnecting the battery terminals...but no such luck...the "EEEE" still
appeared when I turned on the radio again.... WHAT TO DO? WHAT TO DO?

[camper guy]

I get the same code when I use the CD player/exchanger in the trunk but it's only sporatic. Maybe you need the s/n from the radio. The stock radio could have been replaced with a better radio.