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Thunderbird Blues
updated: Aug 16, 2012, 9:46 PM

By Edhat Subscriber

I need to smog my 95 TBird and the "Check Engine" light won't go off, and I can't pass the smog test with the light on.

Two years ago, it was on, and I paid to have it diagnosed to be fixed, and the computer said nothing was causing the light to be on - they ran the test more than once. They told me then that the process of diagnosing the light would "reset" it, and that I would have to drive it a few days to get enough data on it to pass the test. I did that, and got it smogged. Five days later, the light came back on and is still on.

Any suggestions on how to get that light to go off without having to spend more than $100 just to have a diagnosis? Is there a fuse that I can take out? I have been told that disconnecting and reconnecting the battery can be detected during the smog test.

All suggestions are welcome, as my registration expired, and I already got a parking ticket and don't want to push my luck. However, I do not have a lot of money to spend, and just the registration, and the smog test will be around $150, plus the parking ticket ($25 if I fix it within a week, $168 if I don't), So, please HELP!

Comments in order of when they were received | (reverse order)

LIMES	2012-08-16 11:52 PM
I had the same problem--ended up having to get a new catalytic converter installed. I'm afraid it's not cheap to do in California because of emissions standards (which are a good thing). Sorry and good luck!
COMMENT 309347	2012-08-17 06:16 AM
My check engine light came on the day AFTER my smog check. I have a '96 f250. I was able to reset the computer by disconnecting the battery and draining any residual power by pressing the brake pedal and horn. (power is stored for x amount of time to keep computer up to date if you ever have to disconnect the battery). You can google this, and perhaps you will get lucky. I believe the smog check made my light come on, because it never came back on after I reset the computer.
COMMENT 309362	2012-08-17 06:54 AM
I'd post a link, but I can't, so here's some quoted text: "The OBD port is under the hood near the air box. [...]the 94 (and 95) 3.8 is still OBD-I. The 4.6L cars for these years are fully OBD-II compliant however[...] You do not need a code reader to pull codes from your vehicle. The diagnostic port has two main connectors, one of which is a single wire leading to a small, gray plug (closest to the front of the car). Ground this wire and you can perform either the KOEO or KOER tests, and the codes will flash on the "check engine" light on the cluster. Do a couple Googles for the code meanings and test procedures. The best way to clear the codes is of course to fix the problem and let the computer identify the issue no longer persits. However if you pull the PCM fuse (#15 in the underhood fuse box near the battery) or disconnect the battery the codes will be erased. If the issue the code was pertaining to was not corrected however, the code will of course reappear."
EZ2	2012-08-17 07:33 AM
682-0101 gm auto and smog they are the BEST!!
FLICKA	2012-08-17 08:14 AM
My "check engine" light has been coming on for a few years, caused by a computer glitch, according to my mechanic. I finally put a piece of black tape over it. Car runs great!
COMMENT 309404	2012-08-17 08:27 AM
Early 95 *should* be obd1, late 95 might be obd2 (96 was the first year all cars were required to be obd2). If it is obd1, you may be able to pull the code yourself if you look for the process online. The thing is, I recall Fords needing an oscilloscope or multimeter to measure pulses to determine the code number. Some obd1 cars are as easy as putting a short jumper wire into a connector, turning ignition on, and counting the number of pulses of the check engine light. If your car IS ob1, the smog tech won't plug anything into it, so he will have no idea whether or not you reset it right before the test or not. If it is obd2, the computer gets data from the ecu to see that the car has checked all parameters (sensors, etc.) for proper functionality. Obd1 is a little more rudimentary with codes, so if you do pull a code, it may lead to multiple possibilities. Hopefully its something fairly stupid like an o2 sensor. With any luck, you'll have a simple 1 wire o2 that is about $30.
COMMENT 309429	2012-08-17 09:08 AM
I'll second GM auto for smog check. Been going there for years, never a problem with my car passing.
COMMENT 309438	2012-08-17 09:20 AM
aamco checks it free....I think.
COMMENT 309559	2012-08-17 11:41 AM
For $30, you can buy a scan tool on amazon that will give you the code and turn off the light.
COMMENT 309570	2012-08-17 11:57 AM
Could be the type of gas you are using? Try quality gas like Shell if you don't already and see if that helps.
COMMENT 309738	2012-08-17 06:02 PM
I think AutoZone will pull the code for free if the car is OBD-II.
COMMENT 309774	2012-08-17 08:12 PM
A loose gas cap can cause the light to come on. Make sure the cap is on tight, turn it til it clicks or is tight. Inspect the cap also for cracks and replace if necessary.
COMMENT 309892	2012-08-18 11:23 AM
Garcia's Auto at the south end of Kellogg past the drive in is excellent all around but extremely good and fast on the smog testing and willing to do older cars. He has the most reasonable prices too on parts and labor and I've sent a few friends there who were quite pleased too. Usually no appointment necessary too but it never hurts to call. Nice family owned and operated business My check engine light comes on now and then and it is usually a leak in the gas tank pressure so a fill up and tightening the cap well often puts it out. Tell them Human sent you.

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