Will give it a shot Bill, thanks. However I have run the car with the star connector disconnected and still got codes/lights/etc. in addition, the ignition switch is brand new. The car starts without difficulty and I can drive it. As for the NO COMM....I get them from the BCM, PCM, SDM, IPC, sometimes all at the same time sometimes not. If I turn off the car and restart it usually disappears.........it has to be some intermittent grounding issue. Also, and I don't know how this fits in but there are times the tach will hiccup from idle to 2000 instantly and then back....just the tach NOT the engine or actual RPMs. As I see it, it must be coming from a ground, connector or wire that accesses all of the affected modules. All I can deduce from the schematics are the serial 2 and star connectors. Guess I'll go give it another whirl. Thanks again Bill......

 

You have a LOOSE connection somewhere. The MOST COMMON loose connection is the door power connector. Unless you have checked each female pin with a spare male pin to see if the connection is tight, your missing a chance to find the issue. If you don't have to force the pin IN and yank it out, the connection is too loose.

BC

 

OH,,,,,,,,,,,,, Ive seen LOTs of issues caused by the Drivers SEAT connector. Its gets lots of wear and tear cause it close to the floor and the seat runs over stuff when it moves

 

I took the driver side apart twice yesterday, albeit I did not use the male pin technique. The connectors appeared tight, no corrosion.....but no, I did not use the male pin. Bill, I'm not arguing with you, so please educate me....the door connectors don't seem to connect with some of the modules I'm having issues with, at least in my uneducated read of the schematics. I can't figure that out, it seems to me it would have to be something more upstream with potential connection to all of the affected modules. The only thing I can be sure of is that there can be NO way all of the modules are acting up at the same time. What do you think about ground G104? Seems to be responsible for quite a few modules and likely subject to much pushing, pulling, heat, moisture being near the battery tray. What say you?

 

The upstream connector from the OBD2 port is the "star connector" at the left of the passenger footwell. It is the interconnect between the OBD2 connector under the dash with all the other computers on the bus. If you've had HVAC or udder pluggage resulting in leakage in that area, you may have corrosion.

The OBD2 serial bus is a 1-wire system that is isolated from ground, and all messages are sent to all members of the bus. All members receive all messages, but ignore messages that are not destined for them. A loose wire will just prevent one module from send/receiving with the others on the bus. But when an intermittent short occurs to ground, all messaging on the bus is silenced while the short persists.

As Bill said, the common failure points are the wiring to both door modules and power seats, but you isolated them all by pulling the 4-wire star connector. You could try to disconnect individual legs from the 10-wire Star Connector 1 to pinpoint the fault. However disconnecting the end-devices doesn't isolate the wiring looms that may also be the issue. The right way would be to remove the 10-wire star connector plug and incrementally jumper one device back onto the bus at a time until the problems reappear. As Bill said, at least have the PCM and BCM connected to get the car started.

Todd

 

Well. So I removed battery, moved fuse block, and easily cleaned up the ground at G104. Checked the connectors around the area and then buttoned it back up. 20 miles and not one code thus far. I'll keep driving it (absolutely!) and let you all know what happens. It's actually running better too. Was it the ground? Was it the jostling of the fuse block? Many possibilities.

 

Success!

I started at the G104 ground, sits on the rail right next to the battery tray. Took it apart, cleaned it and then buttoned it back up. Voila! Not ONE code since. NOT ONE!
While I know there are many ways to skin a cat, the consistency of U1016 and U1096 in each of the modules suggested a loose, intermittent wire or ground. The schematics show almost every module i had issues with grounded by G104 (IPC, PCM, TCS, SDM, and a few others)........so, to my fellow Vette freaks I humbly submit this for those of you plagued by irritating gremlins......and thanks to Bill and the others who provided me ideas.