This is my first time on this board. I'm a college student and full-size RWD enthusiast, and after 4 years with an '87 Ford Crown Vic I moved up in the world and bought a 1987 Cadillac Brougham, Cotillion White with white leather and 69,000 original miles for $3500. It's the closest I could get with my budget to my real dream car, my late grandfather's gold 1959 Sedan DeVille (long gone, he bought new DeVilles every 5 years) that my dad got to drive to his high school prom in '63 (that must have been fun).

Anyway, prior to buying the Brougham I had my mechanic inspect it and he said it was in excellent shape, except the check engine light was on. Having seen check engine lights before and knowing that usually means a cheap sensor fix, I was not concerned. After buying the car, I brought it in. He scanned it, and the codes for the oxygen sensor and the throttle position sensor came up.

I had both sensors fixed. The car ran slightly better. But the check engine light is still on! Sometimes, I'll start up the car and it won't come on at all in an hour's driving. Then I'll stop, get out, get back in, start it again, and on it comes. Usually it's on though. I checked the gas cap, which was a little worn, and replaced that, thinking that could be the problem. I put carboretur cleaner in, both the kind you put into the gas tank and the kind you spray into the carb itself. Neither seems to have changed anything.

Any ideas on what this could be? A short? A mechanic with scanning equipment that is too primitive (he has pretty low-grade stuff as it is a Meineke but he's "my" mechanic and has been for years)? Is the carboretur itself going? I'm getting about 14-15 mpg in town and 19-21.5 highway which seems normal and the car seems to be running fine.

Currently I have a piece of black tape over the light because it's so annoying. But I'd like to see if there's a real problem and I'm not sure how unless maybe I go to another mechanic.

This is my first time on this board. I'm a college student and full-size RWD enthusiast, and after 4 years with an '87 Ford Crown Vic I moved up in the world and bought a 1987 Cadillac Brougham, Cotillion White with white leather and 69,000 original miles for $3500. It's the closest I could get with my budget to my real dream car, my late grandfather's gold 1959 Sedan DeVille (long gone, he bought new DeVilles every 5 years) that my dad got to drive to his high school prom in '63 (that must have been fun).

Anyway, prior to buying the Brougham I had my mechanic inspect it and he said it was in excellent shape, except the check engine light was on. Having seen check engine lights before and knowing that usually means a cheap sensor fix, I was not concerned. After buying the car, I brought it in. He scanned it, and the codes for the oxygen sensor and the throttle position sensor came up.

I had both sensors fixed. The car ran slightly better. But the check engine light is still on! Sometimes, I'll start up the car and it won't come on at all in an hour's driving. Then I'll stop, get out, get back in, start it again, and on it comes. Usually it's on though. I checked the gas cap, which was a little worn, and replaced that, thinking that could be the problem. I put carboretur cleaner in, both the kind you put into the gas tank and the kind you spray into the carb itself. Neither seems to have changed anything.

Any ideas on what this could be? A short? A mechanic with scanning equipment that is too primitive (he has pretty low-grade stuff as it is a Meineke but he's "my" mechanic and has been for years)? Is the carboretur itself going? I'm getting about 14-15 mpg in town and 19-21.5 highway which seems normal and the car seems to be running fine.

Currently I have a piece of black tape over the light because it's so annoying. But I'd like to see if there's a real problem and I'm not sure how unless maybe I go to another mechanic.

First off, congrats on the Caddy. That gas milage sounds good to me so I would worry about a carb rebuild. Your mechanic could have not correctly adjusted the TPS sensor, which is why you are getting the Service Engine Soon light.

Next, pull the codes from the car and post them here and the members on this board will help you out. To get the codes with the car running or key in On position, press "OFF" and "WARMER" at the same time for 4 to 5 sec. and the climate control will dispaly "-1.8.8." then the codes (ie 12, 34, etc) and then "7.0", which is the end of that diagnostic level.

hello. first time here.

my check engine light has also come on recently. i let my brother take the car to his atuo shop calss to put it on the scanner, but the computer wouldnt communicate with the scanner.

the car doesnt seem to run any different. i wont pull the bulb or put tape over it, cause then ill never get it taken care of properly.

i currently drive with my hand positioned on the wheel so that my fore-arm blocks the light. but every time i turn, it still there.

it used to come on occasionally and sometimes it wouldnt come on for a few minutes into a trip when it did. now it is always on.

any advice?
thanks

hello. first time here.

my check engine light has also come on recently. i let my brother take the car to his atuo shop calss to put it on the scanner, but the computer wouldnt communicate with the scanner.

the car doesnt seem to run any different. i wont pull the bulb or put tape over it, cause then ill never get it taken care of properly.

i currently drive with my hand positioned on the wheel so that my fore-arm blocks the light. but every time i turn, it still there.

it used to come on occasionally and sometimes it wouldnt come on for a few minutes into a trip when it did. now it is always on.

any advice?
thanks

I would guess that your ECM is shot since the car was not communicating with the shops scanner. Try to see if you can get into diagnostics as I explained in the reply right before yours and go from there.

i tried holding down the "off" and "warmer" buttons for a more then 4-5 seconds, both with the car running and with the car off and the key in teh run position.

the display only showed the desired temperature.

I seem to think that display on the temp. panel is only on the 4100 cars. In any case, the diag. plug is under the dash just to the right of center. There are 2 rows of terminals. Short together the 2 farthest to the right on the top row, then turn the ignition on. It will flash 12 on the check engine light 3 times, then get ready to count the flashes because the codes flash next. Each code will flash 3 times and when it's shown you all of them, it will flash 12 three times again.

The only warning I would like to offer is that just reading codes can still turn into a hit or miss game of parts changing. Sometimes a good educated assumption can be drawn that solves the problem, other times it ain't so easy. That's why those little code readers are $50 bucks and a scanner is $3000. It is very helpful to see real time data of what the systems are doing and you must be capable of understanding it. I'm not trying to discourage anyone, but don't spend a fortune buying parts you don't need if the problem gets stubborn. Get someone who knows what they are doing to diagnose it in person.

Yeah, I think I may just take my Check Engine light into another independent mechanic in the area who has a really state of the art scanner...he fixed another problem my regular Meineke mechanic (who was honest about this and did not charge for finding nothing, thankfully)couldn't find on my Ford due to his handheld scanner.... so maybe this other mechanic can isolate my check engine problem too.

Thanks for the suggestions and help above. I did try the "off-warmer" thing but I think the other person is right, that that only works on the HT4100 cars because all I got was the current temperature on the climate control system.

Since off and warmer didn't work your best be is like you stated to take the car to the other shop. Since barge master has a 5.0 FWB go with his suggestions as I know many things for the 4100 and 4.5 (few for Northstar), as I never had any experience with the 5.0/5.7 engines. I just thought that off and warmer was a Cadillac thing for all Caddys, but I guess not.

I'm pretty sure there was another post a while ago that talked aboutnot being able to get codes the normal way too. With a carburetor it probably isn't complicated enough to need them. You can get codes the normal way on the 90s Broughams.

A friend of mine has a 1988 DeVille and it didn't work with a scanner either. This was before you could buy cheap scanners. But on it the codes did work through the display on the dash properly.