Dont feel bad,,, I do the same thing. Jump on a post that 5 6 years old..

Have you read your DTCs??? Read and post your DTCs.

I have a STRANGE feeling that you have an IGNITION SWITCH ISSUE


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.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!



Bill

 

 

BCM ?

The tune exist inside the PCM.

To answer your question about the BCM, YES, they should be the same BUT,,,,,,,, the Tire pressure sensor system will NO LONGER WORK on your car if you install a ZO6 BCM.

You can use a GM Tech2 to program that RPO Function back into the BCM and then it will function again. ZO6s did not come with tire pressure sensors or the monitor ability. I programmed that RPO into my 02 ZO6 shortly after I purchased.


REMEMBER,,,, You MUST sync/handshake the BCM to PCM for the car to start and run.

Bill

 

Thank you so much

 

Hi Bill, I have a question for you. I have a2001 c5 Corvette, ok 2016 I sent the ebcm to get fix, everything was working ok after that fix, then I put my car ok storage, on November 2017, winter, I pulled it out on March 2018 this year, I disconnected the battery for those months, when I picked my car up I reconnected the battery and when I try to start it up I got the normal messages on dic, Corvette, by GMC, but the third messages was check engine soon, as soon as I started my car this third message went off. I checked the codes and I found u1040 and b0432, I sent back the ebcm to get refix, and put it back on and the codes are still there. I should tell you that 2 times out of 6 starting cycles, same messages, but the abs and active handling lights have came on and after starting up the car after few seconds the abs light goes off and the active handling light remains on, I have checked the codes and besides the two that I said before I have found p15725 and c1277, I cleared those codes but as soon as I clear the c1277 and p1571 I have heard a crack noise coming from the engine compartment and the light goes off immediately, the car runs ok without any issue. By the way I put a brand new battery.
Please tell what do you think could be the problem.
Thanks in advance. Every time that I have cleared the codes the car runs very well, and the codes that are always there are u1040 and b0432.
Thank you so much

 

B-0432 is the Rear Defoger relay Circuit
U-1040 is the Lost Communications, Loss of Class 2 Communications with ABS


For the U-1040, You FIRST have to verify POWER & GROUND to the module. You MUST use a Multimeter and read voltage at the TOP of each EBTCM fuse at the fuse test slots to chassis ground.

Voltage must be full battery voltage. NOTE!! Some fuses require the KEY to be in RUN to put power on the fuses.

There should be FOUR ABS fuses. Two large fuses and two small fuse.

 

IF,,,,,,,,,,,,,,,,,,,,, You have proper power and ground to the module it should work and communicate. If not the module is defective OR the serial data line is damaged.

 

Thank you so much Bill, I'll do everything that you said and I will let you know

 

can you send me the link, 1999 are different from 2000, i need a 1999. thanks

 

Bill, you should know this weird thing that is happening to my car.
As you know it's a2001 c5, automatic. The codes are showing up more often, yesterday and today the active handling light stayed on after the car star up, I came home and I tried actron scanner to read and delete all codes, the ones that I said on my last post, but the weird thing is that as soon as I connect the scanner and try to communicate with the car all the codes were delayed, I didn't press the erase key, then I tried the scanner on my dodge caravan and it worked perfect.
Bill, again what do you think could be? I checked all the grounds, fusses, etc
Please let me know what do you think ?
Trucker

 

Alli the codes were deleted, no delayed, sorry, typo