Hey everybody, new caddy owner here, i just bought a 1990 fleetwood, i got a check eng light, how can i decode this? the dealer said they can only decode after 1996 models and up. so mine being a 90 they cant decode it. any websites i can get it decoded from? \
Thanks for any help you can give me

 

it's probably an o2 sensor or egr valve malfunction. if the light stays on and does not flash, that's probably your problem.

 

thanks 1997 caddy, im having the EGR replaced tomorrow hopefully that does it.

 

i agree with the above posts, check your oxygen sensor, it might need some replacement.

 

If it has a cpu in it probably an ODBI and not ODBII if so you can short 2 pins I think A and B together or to A to Ground and you should get some flash codes on your dash. The Check eng light will flash like 2 times pause 3 times =23 this is an example it will flash codes 3 times and move on to the next code.


Just look up ODBI or ODB1 as it’s called. On Google.

 

i have a 1990 fleetwood 4.5 and codes can be found online as well as capable of reding them with the heater conrols . if they are telling you they cant read them then they arent mechanics or you have a 1990 cadillac different than the others i have seen . all of what you need to know is online or in the factory manual . you can even turn on and off injectors to troubleshoto a miss.

 

funny he said he has a 90 cadillac LOL.