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I have had a very similiar situation with my 93LT1 VERT, this car has been down since 10/09/2005, it has had 3 different shops to work on it, and now I am confident this shop will resolve my Issues.

1. Car has had several 4-5 ECMS installed work intermittenly and shut down.

2. CCM replaced to no avail.

3. Serial data loss

4. wiring harness issue.

At this point my mechanics says there is so much corrupted info between all 4 systems this car is severly confused. It sees different info everytime it goes into startup mode. He will have to reprogram several times in order for the car to recognize what it should do consistently. He has by passed all vats issues and currently has a key fob programmed and it works car didnt have a fob when I purchased it.

FEED BACK PLEASE Thanks KRYPTONITE
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1972 LS5 ASPHAULT EATING SHARK

 

Still fighting that beast huh?You have not much luck with it it seems but I can't buy your current wrenches concept.As long as the prom has stock programming it will learn what is correct for your car.It really sounds like a wiring issue possible short somewhere.Loss of serial data is what makes me think that.It may be getting corrupted by the short.If you have more info on what has been done step by step and any codes it threw it might help to shed some light on the problem.I bet you had a quad driver fault at some point didn't you?Points to a wiring problem since you have replaced the ECM multiple times.

 

1) If the ECMs are working and then shut down, I would guess a wiring/power issue is causing them to become corrupted. I agree with Redeasysport that any good ECM should have learned what it needed to know without failing. Even with other significant issues, it shouldn't become inoperable to the point of failure and need for replacement.

2.) If the ECM and CCM were both replaced to no avail, you have a wiring issue with power shorting them out or doing something "illegal" with respect to input voltages. It may be time consuming, but voltage levels and grounds need to be checked at each ECM terminal.

I am not an expert, but I know of NO reason why your machanic would need to reprogram the ECM/CCM more than one time. WHAT is causing the programming to become faulty? It should NOT happen unless there is a significantly incorrect wiring issue corrupting the programming. You solve that, you solve the programming issue.

Ease Diagnostics sells emmissions control software including the software and hardware to Flash reprogram the GM ECM and CCM in 93 and later cars.
On-Board Programming (In Vehicle):
- 1993 and newer GM Powertrain/Body/Chassis flash reprogrammable controllers
- 1996 and newer Saturn Powertrain/Body/Chassis flash reprogrammable controllers
Off-Board Programming:
- 1993 and newer GM Powertrain flash reprogrammable controllers

Their systems use GM supplied bins and are certified in several states for official use as well as by GM. You might send an email to the Emissions Products Sales people at Ease. emissions@obd2.com
Ask if they have sold to a shop in your area that does flash reprogramming. Call that shop and see what they say about the reprogramming issues you are having.

 

The way the system is partioned and based on what the ECM versus CCM tasks, it is very unlikely the system is confused. If the serial link is down, the CCM will set a code and will not be able to communicate with the ECM and the EBTCM.
If the serial bus fails while driving, the car will not shut down if engine is on. Turn the key off and the car will not restart until the com link is re-established (part of the security logic).

 

This may not be relevant, but I'll throw it out anyway. I was having similar problems, and it turned out that my previous AC Delco battery post had been leaking and sending acid through the cable. The entire fuse block was corroded, fuses were covered with white crap. Replaced the cable, block and fuses, and it solved the problem. I'm talking about the fuse block under the hood on the driver's side. Check it out, see if the fuses have turned white. May be totally off base, but is an easy check.

 

Sounds like a better diagnosis than the Corvette Alzheimer's tripe from the mechanic.

 

i don't know about the mechanic, but i've got crs something awful.

 

Check the grounds for the ECM, they are located on the chassis next to the battery. Take them off and clean them and the chassis with sandpaper then reinstall with dielectric grease.
It appears you have an intermittant connection problem and a bad ground will cause the ECM to shut down and not communicate to the CCM