Trouble code P0603 means:Internal control module,keep alive memory (KAM) error
Trouble code P0730 means:Incorrect gear ratio
Trouble code P0100 means:Mass or volume air flow circuit malfunction
look behind the panel on the right side of your trunk where your jack is stored
02 oxygen sensor circuit malfuction bank 1 sensor 1
Trouble code P0011 means:"A" camshaft postion-timing-over-advanced (bank 1)
It could be brake fluid, badly adjusted emergency brake sensor, some other problem with the brakes... a dealership code scanner can tell you what's wrong.
Trouble code P0420 means:Catalyst system efficiency below threshold (bank 1)
it's your 'maf' = mass air flow sensor. easy to fix, pretty cheap at about $150 from rockauto.com or a good online source. do NOT buy from the caddy dealer! go to cadillacforums.com and either peruse or better yet, join the catera/cimarron group for some real in-depth answers to ALL things catera. trust me.
P0071-Ambient Air Temp. Sensor Range/Performance
haynes techbook automotive computer code electronc engine managament system
go to the dealer ( Cadillac or subsidiary) near you and take your VIN number they will find out the code to unlock your stereo, it is caused because the batery was diconected or discharged, the memory of the stereo keeps watching for the vin number stored in memory but if you loose it you need a code, this kind of stereos only work on Cadillac, do not try to install it on a Nissan it won work, or any other car that is not the original. ha ha ha ha reddragon.
the code is 1989 cadillac Devillle and i am not kidding