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Check engine soon light

i have a 1984 cadillac eldorado barritz that runs just fine. the check engine soon light came on. what causes this to come on,and how do i fix it?

It might be a mileage counter saying it’s time to change the oil. It might be some malfunction in the engine, and you should get a mechanic to check it out…soon.

Any failure of an emissions control device will cause this to come on. There is a procedure to cause the check engine light to blink out a code or codes that a mechanic can use to decipher the problem. This vehicle is not OBDII compliant so most code readers will not work.

Failure to repair can cause other problems with the engine later on, expensive problems.

1984 is a long time ago and much of what is true now didn’t apply then. In addition, there is a kind of silly confusion between “Check Engine”, “Malfunction Indication”, “Service Engine Soon”, “Service Engine” lights. Some cars had two lights – one indicating something was wrong, the other indicating that some periodic maintenance is required. The terminology isn’t all that consistent. A “Service Engine Soon” light might not mean anything other than you are due to have the seat covers dusted off or whatever. Whereas a “Check Engine” light almost always means something wrong – which may not be either expensive or important to fix.

If you normally have your car serviced at a dealer, call them and ask. If you are allergic to dealers, maybe ask in a Cadillac specific forum.

You can use the Check Engine light to retrieve the codes.

Locate the ALDL connector under the dash below the steering column. Using a paper clip or jumper wire, plug into the A and B terminals. Turn the ignition switch to the run position so that the dash lights come on, and the Check Engine light will stsrt flashing codes. The codes will appear as a series of flashes and pauses and each code will repeat three times. So for example a code 24 will appear as **-****. Here’s a list of the codes


An '84 Caddy doesn’t have OBDII.

It does, however have BOV8: big ol’ V8