Hi was wondering if anyone could help me out with a strange problem 
Recently bought a 2001 190zt with a standard tape player with cd changer in the glove box, problem is it plays the radio and a long code comes up on the panel beginning with "SN" I can still use the volume on the steering wheel control but nothing else! Even the on/off button won't work??? Anybody experience anything similar or know any way to reset it????

Recently bought a 2001 190zt with a standard tape player with cd changer in the glove box, problem is it plays the radio and a long code comes up on the panel beginning with "SN" I can still use the volume on the steering wheel control but nothing else! Even the on/off button won't work??? Anybody experience anything similar or know any way to reset it????