Cadillac Repair: Erroe code 51, flat blade, prom chip

Question
I have a Cadillac Deville 1985 with 4.1 motor...an just put a new computer in it ..now I have an error code 51 showing up.What does this code mean

Answer
Hi Thomas,

       Most times it means that you didn't change the prom chip from the old ECM/computor to the new one. There is a small cover held on by a 7mm screw and underneith is the prom. There should be a removal tool that is used by placeing it on one end of the prom and prying it up. What I do is work one end up alittle bit and go to the other side and pry it up. Reason being is that the prom pins are very easy to bend. A small flat blade screwdriver can be used if the tool isn't there.

     Once you have it out look on the bottom side where the pins are to make sure they aren't bent. It is made to go in only 1 way so make sure to line it up, place it over the socket and try to push straight down.

    If you already transfered the prom then maybe a pin was bent. Otherwise the computor could be defective. When installing the ECM or prom ALWAYS have the key in the off position or out of the ignition because the sudden electrical surge through the ECM can damage it right away or cause it to go bad prematurely.

    Hope that helps. Bill