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1995 Buick Regal Check Engine Light and Diagnostic Trouble Codes

I have a 1995 Buick Regal 3.8 v6 and the check engine light comes on sometimes, like once or twice a day seemingly random (with 30 min driving). It also randomly will go off, and always turns off after turning off the car and turning it back on. Also occasionally it will lurch about a bit for about 10 -15 seconds (once every 3 days). I have tried to get the diagnostic trouble codes but have been unsuccessful so far. The connector is 12 pin so I am assuming OBD 1, but the pins aren’t in the normal places and I have tried shorting them all with each other but my check engine light doesn’t flash to give me the codes. The pins are located as below


X is nothing and O is a pin.

Does anyone know how to get the codes? Thanks.

Take A Look At The Red Notes On This Site.

I’ve got a couple of 80s Fieros with OBD (1) and they have the appropriate pins and getting codes by jumping A & B is no problem. Your Buick may be one that requires a scanner.


Looks Like Even This Inexpensive “Scanner” Has A Disclaimer For 94-95 Model-Years.
"•1994 & 1995 GM vehicles were equipped with several different engine computer systems."
"•Compatible with OBD I 1982-1993 domestic GM and Saturn vehicles";jsessionid=2703DEC5B0A68968A0322318FF7C0B35.diyprod1-b2c11?counter=1&itemIdentifier=5390_0_0

I’ve never tried it, but a couple of sites suggest that Autozone can pull these old 2-digit codes. I guess you could try.


Thanks for your help. Autozone couldn’t do it but there is a local CarX here and they pulled the codes for free. The dealer said they charged 75 dollars to do it. Thanks again!

You’re Welcome !

What’d you find ?

Oxygen sensor ?


 Well the codes they pulled were for a bunch of things so they reset them and wanted me to drive around to get "fresh" codes.  I drove around for a while and when the light came on I took it there and the active code was the Exhaust Gas Return system.  I have the factory service manual to I took it home and did the diagnosis chain down to either faulty wiring somewhere, a bad PCM, or a faulty EGR valve.  I took off the EGR valve and left the lower part in some gas additive overnight to try and clean it up if it was sticking.  I also ran some sea foam through the car.  Fun.<br>     Well I still was getting the same problem as before, and I couldn't go down the diagnostic chain anymore without a GM Tech1 scan tool,  so I took the car back to CarX.  There were a bunch of codes again so they tried to reset them but they wouldn't.  Basically they couldn't talk to the PCM so they grounded the system but still couldn't talk to the PCM.  They poked around for about an hour and a half and couldn't figure out anything.  This took a while so they charged me 75 dollars.  That seemed fair.<br>     They said they couldn't figure out what was going on and said they think either wireing or the PCM was bad but it would be 150 dollars to check the wiring.  They recommended that I get a PCM from a salvage yard and switch it out, but the problem is that there is a chip in the PCM that has to be reset for my car and they can't do that.  The GM dealer will do it for 125 dollars.  <br>     Oh and the car is lurching a lot more frequently now, but the check engine light comes on still at about the same interval as before.  <br>     So any suggestions on what I should do?  I am pretty lost here and the CarX people seem to be lost as well.  I'm 26 and this was the first time I had to pay the mechanic : (  <br>