Service engine soon light

[ricosuave420]

Today I was driving through town in a bit of traffic, I stopped a few places, in total about 2 hours, with drive time being about 45 minutes of it, it's 92 here today, I've got a 93 ssei with 190k, and in the last 10 minutes of the drive the SES light came on for about 10-15 seconds, then went off for about a minute then came back on for again 10-15 seconds then off, happened about 6 times before I got home, I know it's hot out but I just did a coolant flush about 6 weeks ago and the temp gauge was normal, I didn't feel anything rough running, does anyone have any ideas. Never happened before today, I've got obd1 so codes are gonna be a pain in the ass, I read it may be the O2 sensor, I don't think I've ever changed it, atleast in the 6 years I've been driving it

[J Wikoff]

Might be an EGR valve. I think they can stick open when letting off the gas or something like that. It's been a while, but it happened to me. Took it off, sprayed the pintles real good with carb cleaner, put on a new gasket, and went on my merry way.

Pulling codes is easy before 94. Just put a jumper between the two proper pins of the OBD connector, and watch the CEL flashes. It's in Techinfo.

[ricosuave420]

The air intake temp sensor is not connected to the intake because I made a custom intake and haven't drilled holes for it yet, but it's been like that for months, today is the first warm day this year that I've pushed the engine like this, could that sensor be the problem?

[ricosuave420]

Well the car isn't running rough or anything when the light comes on, it seems to run just fine, would my mechanic be able to pull codes?

[MKMike]

Well the car isn't running rough or anything when the light comes on, it seems to run just fine, would my mechanic be able to pull codes?

You don't need a mechanic to pull the codes on your 93 Bonneville.
You don't even need any tools to get the codes. All you need is a paper clip.
Easy as pie.
Instructions here http://www.pontiacbonnevilleclub.com/fo ... c8689.html

[ricosuave420]

Awesome, gonna go try it after I get home from work thanks a bunch

[ricosuave420]

Is the a and b closer to the front or back of the car?

[ricosuave420]

Ok, I just tried it and I'm kinda freaking out now, I got a 56 code, quad driver b fault, what does that mean?

[J Wikoff]

Google tells me it could be a stuck open EGR, bad boost control solenoid, or transmission connector harness. If your boost acts fine, and your trans connector is clean and fully seated and clean, barring any wiring shorts, then your egr is sticking. The cel behavior makes me think that's what it is.

[ricosuave420]

Ok that makes sense the egr valve is sticking, bc the car isn't running weird at all, and it only came on at the end of that trip, when everything was super hot and I'm sure the egr was working overtime, it's getting looked at on Thursday, no matter what it is it's getting fixed, not getting rid of the car

[ricosuave420]

Well I brought the car to the shop yesterday and my mechanic said he checked everything that the 56 code would alert for and absolutely nothing is wrong, he said it wouldn't come on at all on the highway, only in town when you take your foot off the gas, and since it won't stay on for more than 10-15 seconds at a time there isn't really a way to pin point it, so until it stays on all the time he and I are chalking it up to a case of senior-itis, does anyone have any idea what's going on here or is it just a simple case of the car is old and throwing a false check engine light?

[J Wikoff]

That is how it acts when an egr is stuck open...

[ricosuave420]

Well the egr was replaced and still getting same code, any ideas?

[J Wikoff]

Did you try unplugging the bcs or reseating the trans connector?

[ricosuave420]

Well my mechanic did the work, he said he checked every thing related to the code, not sure what a bcs is or weather he disconnected it, but I do remember him saying he unplugged something, mabey the transmission sensor but said the light kept coming on, every time he did something he would drive around town and on the highway and it always came on in town, is there any chance it's the ecu? Bc I found a brand new ecu/pcm on eBay from AC Delco for 70$ including shipping

[ricosuave420]

Mabey you could give me a list of exactly what should be done to troubleshoot and I'll go see my mechanic and make sure he did everything you suggest, please if you wouldn't mind, I'm incredibly grateful for all of your help so far, I'm never ever ever getting rid of my car, I'll drive it till the day I die, which is why I want it to always be healthy, thanks!!!

[J Wikoff]

Well, if I remember tonight, I'll send you pics of the factory service manual pages for troubleshooting this code.

[J Wikoff]

Sorry for the delay... These are the 6 pages that deal with diagnosing a code 56. If you can't read them, let me know and I'll email you higher res versions.

[wintersfire]

Well the car isn't running rough or anything when the light comes on, it seems to run just fine, would my mechanic be able to pull codes?

I went to 4+ mechanics and none of them were able to pull codes for me. I got the it's too old and we only do cars 1996 and above spiel each time. A friend sent me a video of the paperclip trick and I tried it earlier. Really easy and quick. Now if I can figure out how to fix codes 42 and 44 :/

[wintersfire]

Sorry for the delay... These are the 6 pages that deal with diagnosing a code 56. If you can't read them, let me know and I'll email you higher res versions.

I'm just seeing this comment--J Wikoff, could you send me the pages for codes 42 and 44??