Newbie with connection issues......NEED HELP.....Please......

[smartin436]

HI, I have a 95 Corvette LT1 Auto that I would like to learn how to tune. I've done alot of reading and purchased a cable from Reddevilriver. I can get Scan9495 to work just fine but thats the only software that I can get to work. I understand that I need Cats winflash to do any type of reading or programming to my PCM. Once and only once I was able to get it to read the vehicle type. I cant get any connection at all since that one time. I get "Invalid responce from PCM".
I have tried Tunerpro V5 as well, I at one time had it reading but the dash gauges were jumping all over the place.......garbage info.
I did the compatability install and run as administartor on winflash, no help. I have re-installed drivers, checked com ports, changed com ports...etc.
I also have another PCM from a 95 Roadmaster, I plugged it into the corvette and tried to communicate with it and got the same result.

Im at a loss as to where to go from here. I must have the winflash to make any changes.

Anyone have any suggestions on how to make them talk?

Steve

[steveo]

if scan9495 works, that means you have good comms. scan9495 works in exactly the same way tunerpro and winflash do.

it's weird that winflash wont read your bin. since winflash is commercially supported, you may try contacting the author.

the 'vette has a bunch of other devices on the same aldl data line, that need to be 'shut up' properly. i bet that's not happening for some reason. scan9495 is especially good at it.

i might try disabling hvac, the dashboard, all that stuff by yanking some fuses, leaving only PCM IGN, PCM BATT, and the lighter plug fuse in place. see if that gets your bin reading. also try datamaster EE for datalogging just for fun.

[smartin436]

Ill give it a shot............Let ya know what happens

[smartin436]

Unplugged all fuses except IGN and PCM..........same problem..........could not connect with datamaster, plugged and unplugged the cable a couple times.......got out of the car, turned around clockwise, clicked my heels 3 times and still no connection.
I unplugged the 2 ign fuses and tried it and winflash said bad cable connection, put them back in and it said invalid responce from PCM. That tells me that my PC and the cars PCM are talking, but they don't understand each other.......I think...
I though about buying the LT1 tuning package from Tunercats...........I would hate to do that and still have connection issues, cant afford to throw away $160.00 ya know...

[GaryDoug]

I know this is months old, but just in case someone is listening....
The Corvette has a 2nd system controller module (CCM) that supersedes the pcm for the comms bus. My app, Scan9495 works fairly well in getting around the Y-car's CCM (not perfectly). It could be that the CCM is getting in the way of the signals and TunerPro and Winflash are giving up the comms because of that.

[steveo]

is the CCM at 0xF1? many scantools send 0xF1 a mode 8 request to (i assume) disable comms. i've always been curious about 'the other devices' since my cars never have any of them installed, often wondered what would happen if someone used my scanner software on a vette. i think the b-body has some weird crap too, doesn't it...

[GaryDoug]

Yes, it's at F1. My regular version of Scan9495 does not try to silence anything at F1, but it may have a different method of syncing with the returned data. My prototype version for the Vette does use the F1 silence request although it isn't perfect (perhaps I should send both, F1 and F4). I don't know about the B-body but I know some owners use my app successfully.

[steveo]

i think eaglemark knows what the device address of the b-body thing is.

why do you want a different version for a vette?

i'd just send 0xF1 0x56 0x08 0xB1 regardless. if the device isn't there, everything else should ignore it.

[GaryDoug]

why do you want a different version for a vette?
i'd just send 0xF1 0x56 0x08 0xB1 regardless. if the device isn't there, everything else should ignore it.

There is more involved than just the CCM evidently. The best we got while testing with several tweaks was about 95% success rate while scanning. I won't settle for less than 100%, so it remains a prototype for now. If we ever obtain 100%, I may incorporate those features in the main app.