After replacing my engine, I am now getting "Vehicle Not Responding" when I've tried to link up my obd1 scanners to the PCM. These scanners always worked before. The car runs great and has no codes but I am concerned I can't read the OBD. I've tried spare PCM and it can't communicate with it either. Got any suggestions? Please HELP! I am not an idiot and can follow intelligent directions. Here's a possible clue, I also have an old hypertech power programmer and it is able to communicate with the pcm, it must not go through the serial port? I am baffled! It's probably as simple as a ground wire, but I don't see anything disconnected. I'd be so thrilled to get this solved. Spock, help me!

 

Do you possibly have any other device connected to the tan serial data wire in the DLC (pin (M)? If so, it needs to be disconnected when attaching a scanner. I have a Scanmaster wired into the tan wire, behind the DLC, and have a switch so I can disconnect the Scanmaster when using an OBD-1 scanner.

Did you do anything to the DERM module for the air bags, or to the ABS? The tan serial data wire also connects to the DERM. And to the EBCM module for the ABS.

Or, do your scanners have internal batteries? In 94 there’s no 12 volt pin in the DLC to power a scanner.

 

Thank you so much for the reply! I don't think I have anything hooked up to the tan serial wire. The only thing I can think of is I have a VATS bypass that I installed under the steering column. I did disconnect the DERM module (I think) and it didn't affect anything. I have the factory manual which discusses removing modules until the pcm starts communicating. Please let me know any other suggestions you might have. Thanks again!!!!

 

Also, I am aware that my scanners need internal batteries and both scanners worked fine before.

 

I followed up with GaryDoug and he indicates he is dealing with you directly on this problem. Be sure to post the resolution.

 

Turns out its an issue with BOTH of my scanners, because thanks to GURU Gary, I can communicate with the PCM using my laptop, ALDL cable and his awesome program.

 

So, you don't know what was wrong with both of them? You said that they worked before.

 

At this point it is a mystery since it would be unlikely that they would both go bad at the same time. I still suspect there is something going on at the point the cable meets the car connector. Like perhaps some having slightly longer or shorter pins maybe? Or maybe just a coincidence at both being bad?

 

I'm chalking it up to the scanners gone bad, because my hypertech programmer works as does Gary's awesome laptop program. I'm not going to worry too much about it, I've got a functioning scanner now with Gary's program. Thank goodness for guys like garydoug and shbox!

 

I would be thrilled if someone out there can fix the tuner cartridge that goes with my hypertech power programmer. I am getting a memmap error. The tuner works fine, its just the cartridge that is malfunctioning.

 

and Fred!

 

I have a Hypertech I haven't used (or needed) for 18 years. It might not be the “III” version. There is a blanked off opening on the bottom labeled “Power Port”, but I cannot find any way to remove the cover. Is that where the cartridge inserts? I thought (thinking back over 20 years) only the OBD-2 Hypertechs had the slot for a cartridge, including one that could pull codes.

There was a member here who built cables for scanning and programming. He could reset the Hypertech to allow a new VIN. A few years ago he gave up his business. I'll see if I can re-establish contact, to ask if he could help you out.