GM Code reader unable to pull codes from ECM
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Cruising
Joined: Jun 2023
Posts: 10
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GM Code reader unable to pull codes from ECM
Afternoon All; I own a 1994 C4 Corvette. I have a "service engine soon" light that will come on intermittently. My question though is, I can not get any codes out of the ECM with my code reader. My Corvette shop can't get codes out of the ECM. Has anyone else who owns a late model C4 had this problem? Would anyone have an idea why the ECM won't transmit the codes to the GM Code reader? Or, do I need to use the "paper clip" method?
Thanks for any and all help Corvette Forum
Thanks for any and all help Corvette Forum
Instructor
Joined: Jul 2024
Posts: 112
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From: USA
For all practical purposes the 94 is a OBD 1 system. But it does use the OBD2 ALDL connector. A OBD2 code reader will not work if you hook it up.
I believe OBD II started in 96. Other more knowledgeable people will likely chime in.
I believe OBD II started in 96. Other more knowledgeable people will likely chime in.
Team Owner
Joined: Sep 2003
Posts: 25,393
Likes: 2,741
Afternoon All; I own a 1994 C4 Corvette. I have a "service engine soon" light that will come on intermittently. My question though is, I can not get any codes out of the ECM with my code reader. My Corvette shop can't get codes out of the ECM. Has anyone else who owns a late model C4 had this problem? Would anyone have an idea why the ECM won't transmit the codes to the GM Code reader? Or, do I need to use the "paper clip" method?
Thanks for any and all help Corvette Forum
Thanks for any and all help Corvette Forum
Pro
Joined: Aug 2020
Posts: 647
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