I am trying to upload my new tune with Winflash and am having trouble connecting to the PCM.

I have an ALDL cable for 95 cars (which I have used before with no problems on a different laptop) and a RS-232 to USB adaptor.

I figured out which COMM port I needed to plug into and set it correctly in winflash, but when I try to read or write to the PCM it gives an error saying "Invalid response from PCM".

I tried connecting with datamaster to see if that would work, but it gives an error saying "ALDL is working correctly but unknown data was detected, you may have the wrong version". But I am using the correct DM35xEE for 94-95 LT1 F-bodys.

Anyone have any idea what the issue might be? All the pins at the OBD connector look good, my battery voltage is right at 12.2.

 

If you turn the key on and right away try to connect you get an error. What I do is turn the key on and let it sit till it stops dinging, then connect.

 

I've tried it after the key was left on for several minutes and still gives the same messages.

 

Does the car run?

 

Sounds like either a software problem for the cable or you need to change the comport setting.

 

The car runs fine.

I'm thinking it might be the RS232 to USB adapter. Searching the web some it looks like some of them just don't work with tuning software.

 

Re read the instructions for the the aldl installation and once you do that try changing the comport to another one it helps.