Boost-it

Hey guys,


The vette had been stored for around 4 months, when I turned the key on I couldn't hear the fuel pump and fuel pressure reads 0.

I have the CEL on & when checked for DTCs, found one of them is related to "Fuel pump relay"

I wired it directly and drove to the mechanic, after several attempts trying to track down the issue, he said that the relay is not getting a signal from the BCM

and the problem could be with the wire feeding the relay, or worse the BCM itself!!


Any one have an idea about this?

Bill Curlee

You need to find a mechanic that understands Corvettes and how they really work.

- For starters ,,,,, what DTC do you have???

- Have you tried to clear it????

How are you reading the DTC's??

Like this:

You don’t need no stinking predator to read and clear DTCs

The DTC that you have is actually: Traction Control Torque Request Circuit and frequently happens when some other EBTCM or BCM error DTC is present. That predator wont show you ALL the BCM or EBTCM DTC.

Try this. Its more accurate and easier.

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.



NOTE!! If the BCM is having a security issue,,,it will NOT allow the fuel pump to run! So,,,yep,, the BCM is causing you issue. Cause it's DESIGNED that way!

Before you get head deep into your bank account and throw expensive parts at the car, you need to dig a little deeper in the actual issue causing the car to be unhappy.

BC

Boost-it

Hi Bill,


Thanks for stepping in and my apology for the late reply.


A mechanic that understands Corvettes = Stealership ? I do always use the onboard trouble code reader along with HPtuners to see what's going on with my vette. I cleared all DTC's and here are what came back:






Both P0103 and C1241 came after I installed the Novi (running mafless)
but the P0230 is the most recent and came up after 4 months of storage

Boost-it

update:


Today I changed the battery to AC Delco 78A-84 and to my surprise I got more codes


C1255 EBTCM Internal Malfunction
U1064 Loss of Communications with BCM


Any idea?

Thanks,

Bill Curlee

Clear the DTCs several times and see if you can get them to clear. The ones that continue to pop up, we will work them one at a time till you dont have any!

BC

Boost-it

Hi Bill,


I very much appreciate your help, it's encoureging to say that it's possible to make it DTCs free

Boost-it

Update:


I went for a drive today morning and I reset all the DTCs while both driving and with the engine off (more than 5 resets)

The C1255 and U1064 got cleared away successfully but the others kept coming back.

Boost-it

Update:


Had some time off so I decided to check\clean the grounds and to my surprise the G 104 was bent and looked like it was broken:





I thought it would break off if touched but it didn't, so I removed the bolt, cleaned it out and straightened the ground stud and put everything back in and tightened it and it held well

Now got 2 new DTC's for both front and rear knock sensors!

P0332 HC
P0327 HC

In addition to:
P0103 HC
P0230 HC

C1241 C
C1286 C


Any Idea?

Boost-it

ttt

lucky131969

Take it to another mechanic that understands C5's. The fuel pump relay has nothing to do with the BCM. The PCM controls the fuel pump relay, as it supplies 12 volts to the relay in two ways:

1) Key to on, pump will run for 2 seconds if no engine rotation is sensed from the crankshaft sensor.

2) Normal starting, engine rotation is sensed, and 12 volts to the relay is maintained.

The BCM does communicate with the PCM, as it relates to starting the engine, over the class 2 serial buss. If the correct message is sent from the BCM to the PCM, indicating that a security issue does not exist, the PCM enables the fuel injectors. If a security issue exists, the PCM will disable the fuel injectors.....not the fuel pump.

No offense, but that has to be the filthiest frame I have ever seen. Has this vehicle been in a junkyard, wrecked, etc? If that's the way the whole battery compartment looks, I would be inspecting splice pack 122, G105/106, and the PCM wiring as well.

http://forums.corvetteforum.com/c5-t...e-grounds.html