ecm-ccm serial communication problem?

[jaysvette]

working on 94 (c4 eng p auto) car will run for less than minute then shut off. I have "SYS" in display flashing with Security light

DTC code of 41 (c & h) on 1, error on 4 & 9

So if your not lost your the person i need to talk too...
tried three different scan tools, none of them can communicate
with system, but will run things in field service mode.
used Snap-on, delco 2 and accutron

Service manual talks about ground and open circuits in
CKT 800... but can't find any reference to it in manual..
had ecm to dealer and he bench tested it and was able to read vin and software levels they felt it was probally good.
SO where do i go now? any idea's ???

Car interior and dash was taken apart in 97 with damaged floor and cowl from shipping issue. then parked, I have put it back together in last month or so with new floor and repaired cowl but she won't run???
any idea's or help will be gradly appreciated
Thanks
Jay

[PeteB]

I don't have a manual for a '94, but my '95 vin"p" manual tells me that DTC41 is an open ignition control circuit.
This may or may not be valid for a '94, but it seems that they wouldn't change since they are both OBDI.
My manual doesn't reference a CKT800 in the diagnostics.

Here is part of what it says:
"If a DTC41 is detected, the PCM will disable the fuel injectors to prevent flooding of the engine. DTC41 will be stored in the PCM memory but will not turn on the malfunction indicator lamp(MIL)"

Good luck.

Pete

[jaysvette]

Thanks for the input, my local GM dealer tells me 94 and 95 are
different? I have checked voltage at coil and coil control module and it tells me the module "may" be at fault, but then it states car will not fire with bad module?
This one is giving me way to much greif... is there anyplace someone knows of that i can contact that may be able to help? GM number? Speciality shop?
I hate to say it but car is headed to E-Bay as a project or peice by peice pretty soon.
Thanks
Jay (one way to frustrated corvette owner)

[PeteB]

Sorry about that. I thought they would be the same.
Anyway, I did have a car (not a Corvette) that would start but would die right away and it turned out to be the ignition module.
Good luck.
Pete

[jaysvette]

Well the chase continues.. spoke to two experts and one says it's the CCM the other says the ECM.
Both say it may not fix the issue though, on $$ per minute basis you hope one would be definate.
so any idea's or other folks input would be appreciated..
Thanks
Jay

[Glennm27]

This may be too obvious of an answer but I didn't see it mentioned anywhere above, so here goes my suggestion.

I'd suggest Steve Spencer at Bryner Chevrolet take a look at it.

If you DON'T know, Steve is one of the very best GM Dealer technicians and is a Corvette specialist.

My guess would be Steve could tell you quickly what is wrong and what to do after seeing the car and diagnosing it's troubles.

215.886.3140
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AFTER I POSTED THE ABOVE , I THEN NOTICED THIS POST IS COMING FROM WISCONSIN. OH WELL JAY, I GUESS PHILA IS A LITTLE TO FAR TO TRAVEL, ESPECIALLY WITH A CAR THAT WILL RUN FOR ONLY 1 MINUTE AT A TIME.
Hope you can find the fix.

[jaysvette]

Well the car is running and all is well.... a serial communication lead from the engine harness to the dash harness was shorted to ground causing all serial communication to be messed up.
This caused the ccm and ecm not to be able to "talk", well their talking now and she's running fine. Thanks to all who replied with answers and idea's.
Four days with a circuit tester and shop manual and life is good.
Of course it snowed this morning in Wisconsin, just enough to tell me it almost time to put her away..

[PeteB]

That's great Jay. Glad to hear you're on your way.
Please don't send the snow East. We are looking forward to at least another month or so of crusin'weather.