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Help reading diagnostic codes

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Old May 1, 2008 | 10:03 PM
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Default Help reading diagnostic codes

Is there a unit I could buy to read codes? Where does it hook up?

Thanks - John
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Old May 1, 2008 | 11:49 PM
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http://www.actron.com/ this site may help
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Old May 2, 2008 | 12:25 AM
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Originally Posted by 400hp427vette
http://www.actron.com/ this site may help
Thanks but they're too modern for my '82.

I've been doing some searching and found a 3123 gm code reader. The price seems to be just under $50. It looks like a connection tool rather than code display.

Would I get the same results using a paper clip on terminal A & B of the ALDL in my '82 and watching the Check Engine Light?
Is there a thread or site where I learn to read the codes?
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Old May 2, 2008 | 01:38 AM
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Originally Posted by 82crossfirevette
Thanks but they're too modern for my '82.

I've been doing some searching and found a 3123 gm code reader. The price seems to be just under $50. It looks like a connection tool rather than code display.

Would I get the same results using a paper clip on terminal A & B of the ALDL in my '82 and watching the Check Engine Light?
Is there a thread or site where I learn to read the codes?
Yes, you would...or if you go to most auto parts stores, they have for sale (Autozone used to give them away, not sure if they still do) a stamped metal piece that does the same thing. The codes are pretty generic and can be found online or in the service manual.
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Old May 2, 2008 | 07:39 AM
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Actually you can use a paper clip to pull codes on your '82. Pick up a book on code reading at your auto parts store or do a Google search as it is a little too involved to go into here.
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Old May 2, 2008 | 07:42 AM
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Originally Posted by Jud Chapin
Actually you can use a paper clip to pull codes on your '82. Pick up a book on code reading at your auto parts store or do a Google search as it is a little too involved to go into here.
Here's a link for you:

http://www.obd-codes.com/faq/read-gm...codes-free.php
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Old May 2, 2008 | 07:50 AM
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Thanks. - John
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Old May 2, 2008 | 08:01 AM
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You're welcome!
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Old May 2, 2008 | 10:38 AM
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The "check engine" light doesn't come on when I turn the ignition on OR when I try to enter diagnostic mode, paper clip in the ALDL A/B terminals and ignition on. The bulb checked ok.

Is my ECM is gone? It's original at 91K miles on my '82. I swapped the PROM with an Accel hi-performance PROM that's been sitting on the shelf for years and got the same result. However, I would've received an error code on the PROM if the ECM was working.

Can someone confirm my diagnosis?

edit: The car won't start but wants to. New: fuel pump, fuel pump assemble, fuel filter, fuel hoses on the tank. The fuel pump check ok via 12 volts from the ALDL but isn't getting the green light during ignition.

EDIT: New ECM on the way!

Last edited by 82crossfirevette; May 3, 2008 at 07:22 PM. Reason: see edit
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