I have a 90 eldorado that wont start.....when i turn the key on i get a message that" monitored systems ok" then "system problem" blinks twice then "change oil". when i go to start the car everything goes blank and nothing happens. nay clues where to start. I took the key to local dealership and he said they dont have a way to test the key to make sure it is still good.

 

Battery????

 

battery AND oxidised battery posts ? ? ?



.

 

battery is fully charged and post are clean..........now i am getting a message that starter disable due to theft system.....i askedmy borhter-in-law if someone tried to breakin to the car and he said that he had pop-a-lock go in through the passenger side and then it wouldnt start on him.......maybe this is why he sold it to me.

 

This may be due to the dreaded failure of the loop from the theft processor to the ignition switch and back.

Try to fix this by providing the proper resistance to the processor, by-passing the key resistor circuit.

Get your key "read" at any GM dealership, then construct a jumper of the same resistance. Wire this across the circuit.

JCS

 

among other helfull subjects, the VAT jumper that JCS is refering
to, is in our Cadillac Forum FAQ

https://www.cadillacforum.com/m_7872/tm.htm