My 2000 C5 6-speed Hatchback is possessed! It randomly allows me to drive it, in no certain order. It's garage kept, only 67,000 miles runs and drives perfectly, that is when it allows me to drive it. I rebuilt the car from a hard right side impact. Smashed the TAC module, but computer was fine. It cranked and ran perfect up until the steering locked and I put one of the bypass kits on it(under the steering column, not the one that hooks to the BCM). I drove it a few days after that, but the next time I went to drive it, it would spin over, but no fire. I checked it, it had fuel, but no fire at the plugs, so I left it sit in my garage. The next day, I got in the car, put the key in and it started right up. Drove it all day, but never shut it off in fear it not starting up again. When I got home, I shut it off, but it started right up. I was thinking yay!! It's fine, but the next day, the start no run issue. A day or so later, cranked and ran all day. Even started back up at several stops I made...........To make this shorter, it's goes back and forth for several months now. I've checked all grounds, battery connections, fuses, cleaned the 6 or so connectors between the battery and inner wheel well, also crawled under it to clean the TAC module and Computer connectors......then it started up after that, shut it off, got it off the ramps to park it in my garage, wouldn't start. Had to push it in my garage...So!! I have just been driving it when it lets me, lol! The very last thing I did was clean the 2 connectors in the driver door, but same scenario. Everyone tells me it's the security system, but that issue is the key turns on but the starter doesn't spin over at all. Today and yesterday it allowed me to drive it, lol.....Who knows about tomorrow?

 

One thing that you need to do is read and post the DTCs. IF, you have a TON of old DTCs, CLEAR ALL OF THEM. Then when the car decides it doesn't want to work, "WITHOUT TURNING OFF THE IGNITION KEY" press and hold RESET to clear ANY messages in the DIC and then enter the DIC DTC reading routine.

Post ALL DTCs and INCLUDE the suffixes "C" and or "H"

Procedure listed below:

What is the SECURITY LIGHT on the IPC doing when the car will not run??? ON. BLINKING, OFF ????

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READING YOUR Engine Diagnostic Codes



The Diagnostic Display Mode is entered with the following procedure:

1) Turn on the ignition but don't start the engine. NOTE! You can read the DTCs with the engine running and or driving down the road but it can distract you. BE careful! Some DTCs clear themselves when you turn the ignition OFF!

2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.


Initially, on-board diagnostics go into an Automatic Mode which 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. ( 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 kinds of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current C code indicates a malfunction is present and active 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 English/Metric (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 and hold the RESET button 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.
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. You can GOOGLE the DTC and also find information on it.




Here is very good site that explains the DTCs:


http://www.corvette-web-central.com/C5DTCcode.html


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



Make sure to include the H or C suffix!!