How to you get codes from an OBD1?

[V8 Killer]

Car is a '91 Firebird 3.1, check engine light came on recently. How can I scan it and get the code? I heard a rumor that sticking a paper clip in to the ALDL and it will flash the code sequence. Please help, I dont want to pay $100 to have to done at a shop. Whats the most comman code? 02 sensor?

Thanks in advance, 3.4 slow to go :D

[3.4 slow to go]

key in ignition, in off position,

look at this OBD1/ALDL PIC

the top row, the last two slots need to be jumpered, either w/a paperclip[ or a free key from an autoparts store. Or, go to a parts store that offers free checking & have them do it along w/a print out of what the codes mean.

Once the jumper/key is in, move the ignition key in to teh run position. It will flash a code 12 three times (actually, it'll flash all codes three times, and repeat until you move the ignition into the off position) Any codes after 12 will be the problem child/children.

[V8 Killer]

The last two on the top row you said, is that last from left or last from right? You said it will flash a code 12 three times. Code 12 is the light flashing 12 times? It does that three times? Then turn key to off and it will flash the problem code?

I got this right?

[3.4 slow to go]

last 2 on the top right in the pic. see teh nub/keyed part sticking out? that would be the row used. I;ve seen some connectors w/this facing down, but use the row that has the nub.

the nub
the nub

anyway, once the code 12 flashes 3times, it will continue to flash any other codes it has 3times.

yes, you'll have to count the SES light. for 12 it'll flash once, pause, once twice, puase once, pause, once twice, pause, etc

[V8 Killer]

After the code 12 computer acknoledgement, i turn the key to off and it flashes the problem code? Is there a pattern in which it flashes the problem code or should I just sit down and count how many tiems it flashes..

[3.4 slow to go]

do not turn the key after code 12 flashes, or you wont get any other codes. the codes will flash in numerical order. just observe how the code 12 flashes, and you will be able to see how all the others will flash

[V8 Killer]

I got a friend who works at Autozone, can they do OBD1?

[3.4 slow to go]

yuppers

[Fbody3400]

Not a 3rd gen, but the guys at my autozone said they can't scan the '93 3.4

Is this because its OBDI with an OBDII connector? I think thats what it is anyway...

[3.4 slow to go]

my 95 Blazer has the same bastard deal, but the OBD2 scanner will pull codes

[Fbody3400]

Are you serious? So the OBDII scanner will work? I hate autozone, the one around here is ****. The guys don't even have to be certified for anything, i don't even think they need a drivers license... :puke:

[3.4 slow to go]

I was never certified on anything when I worked @ AZ, but then I have a good grasp on common sense, plus prior knowledge on cars. I know the scanner worked because for ****z & giggles & slapped it on myself to find out what the ses lite was trying to say.

[Fbody3400]

Sweet, thanks for the info. I posted a question in Gen tech a bit back but got no replies. Maybe i'll try to coax the guys up there to hook it up and see