I'm not able to connect my laptop to my PCm via the DLC in my 94 camaro Z28. I have a scanmaster connected with a disconnect switch installed so it wouldn't interfere with the usage of the DLC. I've programmed my car several times in the past using Tunercats and the same ALDL cable I'm currently using. Tunercats will not connect to my PCM and I keep getting the message "Incorrect Response from PCM". BUT, when I switch on my scanmaster and try to read PCM it starts like it's gonna read then pops another error message; obviously due to the scanmaster interfering which I undeerstand.

I currently do have my cig/horn fuse out, but I thought that shouldn't matter on a 94. Am I correct?

I'm stomped. Any help would be appreciated.

 

To add, the scanmaster work perfectly fine when switched on so I know it's receiving data from the PCM.

 

What kind of cable? Who was the manufacturer? It sounds like the driver for the able is incorrect and that could occur if the pc automatically downloaded a new one. Or the cable is defective, it happens.
Make sure the pins in the DLC are all in place and one has not pushed out.
If all else fails, try to rollback the driver to the last one used.

 

As far as the cig lighter fuse, correct. There is no 12 volt pin in the 94 DLC.

 

The cable is a 12 PIN ALDL OBD1 cable (part no. aldlobd1u) from OBD Diagnostics. The cable is only a little over a year old. Looks to be in great condition externally. I took good care of it when not in use, but who knows what could've happened. I checked the DLC pins and they appear to be pushed in as far as they can. I'll see if I can get the driver info on the cable and see where that leads me. I don't want to buy another cable without knowing I definitely need one.