Cadillac Repair: 1993 eldorado high idle, sec cycle, battery cables

Question
Hi Ed,I have a 1993 Eldorado with a 4.9 engine.It has been hanging on a high idle when you come to a stop so I bought a new Idle Speed Control for it and installed it and it doesnt help.I dont think the car done this when I bought it but the battery went bad shortly after I bought the car and so I replaced it.I was wondering if it needs to learn the idle speed again?Does this need to occur everytime the battery is unhooked?Is the Learning easy for me to do at home?Thankyou for your help.

Answer
Hi,Wes

Yes you are correct,looks like you need to idle relearn the PCM to the idle control motor,usually you do need to do this if the battery is disconnected or replaced,the condition is called sail on and is common.the relearn can be done at home and ill give you the procedure to this.
 First make sure the throttlebody is clean,and linkage is free no binding,you can clean the throttlebody using gumout or a solvent of that type if all is ok,begin the idle relearn procedure as follows:
 Start the engine and allow to idle until its at normal temp,allow to idle for 13 min,while idleing after 13min enter on board diagnostic by pressing and holding the off and warmer buttons at the same time,the displays should all light  and then PCM ?will appear diagnostics is entered,release both buttons,turn engine off wait 20 sec,key to on but donot start,enter diagnostics again,key off wait 20 sec,do this same procedure a total of 3 times,after the third off wait 20 sec cycle,start engine and allow to idle,press brake and shift into drive,no ac on,and allow to idle in drive with no ac on for 1 min,after the 1min turn the ac to on,and again idle eng with ac on for another 1 min,after the 1 min of idle with ac on,turn off engine and wait 20 sec,restart engine and verify that it learned by road testing and seeing if there is any sail-on,if there is still that problem,then you can disconnect both battery cables pos and neg,short the cables together without connected to the battery for about 10sec,then reconnect the battery,reroad test again and it should have solved the sail-on problem,if not contact me and we can do a further diagnosis,Thanks

ED