Help! 1994 6 speed Code C41

[Jack2052]

I just bought a 1994 Corvette with a 6 speed that doesn't run. The following is the trail I have taken toward finding the problem.

1. Security key does work.

2. Clutch switch does work when I bury the pedal into the carpet.

3. The car starts, runs rough and then shuts off.

4. Checking the codes with the paper clip I got the following.
1. Reads C41, Loss of ECM serial data communication.
4. Reads ERR
9. Reads ERR

5. I did find a lot of corrosion on the big fuses under the ECM. Cleaning it off didn't change anything.

Any ideas? Jack

 

[Jack2052]

Forgot to mention

The Security Light and the SYS light are flashing 3 times. Fuel Enable Data Stream.

 

[vetteoz]

3. The car starts, runs rough and then shuts off.
1. Reads C41, Loss of ECM serial data communication.
Any ideas?

Corvette Forum - View Single Post - Which is failing? ECM or CCM?

Corvette Forum : DigitalCorvettes.com Corvette Forums - View Single Post - pulling my hair out

Corvette Forum - View Single Post - Which is failing? ECM or CCM?

Corvette Forum - View Single Post - Which is failing? ECM or CCM?

 

[Hib Halverson]

The CCM has lost contact with the ECM and likely the car's other processors and that's why you can't read codes using CCM diagnostics.

Do you have a scan tester which supports a 1994 Vette. 94 was part of GM's early roll-out of OBD2 so your car also is likely to have a 16-pin DLC. Most 94s do not support flash code ECM diagnostics so you need the tester.

Do you have the Factory Service Manual? If so, have you run the fuel pressure tests listed in the book?

You say the car runs rough then dies. For how long after you turn the key from start to run does it run before it dies?

 

[Jack2052]

Hib Halverson

The CCM has lost contact with the ECM and likely the car's other processors and that's why you can't read codes using CCM diagnostics.

Do you have a scan tester which supports a 1994 Vette. 94 was part of GM's early roll-out of OBD2 so your car also is likely to have a 16-pin DLC. Most 94s do not support flash code ECM diagnostics so you need the tester. Don't have the tester. I've only had the car a short time.

Do you have the Factory Service Manual? Same as above. If so, have you run the fuel pressure tests listed in the book? I did check the fuel pressure with the switch on and with it running. It was right on both times.

You say the car runs rough then dies. For how long after you turn the key from start to run does it run before it dies? It runs for about 5 seconds and then shuts of as if the fuel was turned of.

The car had sat for a year or two because it wouldn't start. As I found corrosion on those big fuses I expect I'll find it a lot but don't know if that's the problem. It had a few gallons of gas in it so I added dry gas, a fuel system cleaner and 5 gallons of premium to the tank.

 

[Jack2052]

Corvette Forum - View Single Post - Which is failing? ECM or CCM?

Corvette Forum : DigitalCorvettes.com Corvette Forums - View Single Post - pulling my hair out

Corvette Forum - View Single Post - Which is failing? ECM or CCM?

Corvette Forum - View Single Post - Which is failing? ECM or CCM?

Great information. This will keep me busy. Thanks, vetteoz