I have a 2004 coupe and have seen many posts that address my issue with the exception of one thing...when I turn my key, nothing, dash is lit, radio on, air blowing, but never attempts to start. Then, a few minutes later I try again and it cranks, BUT AS SOON AS I RELEASE THE KEY, it immediately dies. ( It may do this two or three times) Wait a minute, try again, and it cranks, no problem. The only fluctuation I see is the voltage reading on the dash. When cranked it is between 13 and 14. When it won't crank...it may read 11 or less. Is this due to the VATS key??? I'm clueless...

BTW, all of this started yesterday. Never had any problems before. Battery tested, good. Alternator tested, good.

 

The FIRST thing that you should do is read and post the DTCs See the procedure below:

Rebuild OR replace your ignition switch!!!

- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html

This is the SECOND ignition switch I helped repair to day!

Bill


READING YOUR Engine Diagnostic Codes (DTCs)
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 etc…)
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 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.
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.

Here is very good site of DTC definitions:


http://www.gearchatter.com


Make sure to include the H or C suffix!!

 

Thanks. I'll have to print this out and try it tomorrow. Will post what I find.

 

You asked for expert advice and you've gotten it. Bill is the man when it comes to this stuff. Igniton switch rebuild is the way to start. It costs -0- and will probably solve the problem but even if it doesn't, you'll have eliminated a highly probable cause of your dilemma.

If it makes you feel better, I had almost the same problem as you. However, mine would crank fine and start every time, but when I released the key from CRANK back to ON, it would die. It was an intermittant problem that would only appear on occasion, then it finally did it every time. My problem was in the ignition switch ON position. I should be getting 12v to the fuel pump relay but there was no voltage at all. Jumpering the fuel pump relay contacts would allow the car to run. I have a mechanical fuel pressure guage that was installed when I changed to billet fuel rails. I could see that when I turned the key to the ON position, there was no pressure at all, nor could I hear the fuel pump. When I CRANKed the car, the fuel pressure would go to 58psi, but after the car started and I released the key, fuel pressure would go back to zero and the car would die. Jumpering the fuel pump relay points, I could then hear and see the proper fuel pressure and keep it running when in the ON position. Bill's ignition repair guide has resolved this for me. Hope that gives you some hope. Bill will help get you through this.

 

Update...and I'm sick. Dropped my car off yesterday at a guy I've used forever just to have him look at it. He called me today and said that from what they could tell I have a bad BCM and possibly need a new key cylinder. $1900 for all. He said that it was throwing out two theft codes and that when he removed the two wires that read the resistance from the key, the BCM allowed the car to crank and run like normal. What do you guys think? Am I really out $2k?

 

Well,,,,,,,,,,,,,,,,,,,,,, lets add a few things up:

New GM BCM = $600ish
Program and install the BCM = 1 hour labor and thats generous
New key cylinder with key sensor and re-pin the cylinder and labor= approx $150

Install the ignition cylinder and switch 1 hour labor

That my friend should be around $950 and we will make it $1000 just to be on the safe side.

If your mechanic moved a wire and the car starts and runs, WHY do you need a new BCM????????????????????????????????????? ?

If I were you, I would ask him to show you the magic wires and bring the car home. I seriously doubt it needs a new BCM at this point.

Until you read and post the DTC, it a crap shoot guessing game.

In MY HONEST OPINION,,,,, your getting hammered for more than a grand and probably more than that!

IF, you end up getting a new BCM, save the old one,,, cause its most likely still a good unit!

Bill

 

Bill - I'm getting car back tomorrow as is, will post DTC tomorrow. Thanks!

 

Ok, got the codes

01-BCM B2592H

99-HVAC BO338H
B0361H

AO-DCM B2282H
B2286H
B2284H
U1016H

A1-RDCM B2283H
B2287H
B2285H
U1064H
U1016H

BO-RFA C2100H
C2105H
C2110H
C2115H