What do I need to pull the codes on my 89 IROC?

 

A paperclip.

Should work the same as Shoebox outlines for the 1993 4th Gen's ECM:

http://shbox.com/1/dlc2.jpg

 

Thanks for the reply. However this did not work. I have the 12 prong type but when I put the paperclip in and turn the key on the SES light just stays illuminated. I would expect it to flash according to the reply. Also the SES light on the 89 is just the words illuminated from behind with a light. With this said the flashing would be what I am looking for correct? As it is not able to give me trouble numbers.

 

Yes.... the light behind the SES opening should "flash". Count the flashes. If it doesn't flash. the ECM is not entering diagnostic mode. Next step would be to try an OBD-I scanner, like the AutoXray.

Are you sure your SES light is working? Does it light up for a few seconds when you turn the key "on"?

 

It remains constant when I turn the key on.