Very Strange "Car won't start sometimes" problem
 

Sometimes when I go to start my 2003 C5 Z06 the car will not start. I turn the key and everything comes on as it should but nothing. I wait a bit, turn the key 5 or 6 more times, wait a bit more, turn it 2 or 3 more times, and BAM it starts right up. This happens very sporadically. Sometimes it happens once a month. Sometimes it happens once a week.

Anyone have any ideas what it could be???

:ack:

Post your codes.....

Is the yellow "Security" light flashing on the dash after a failed start attempt?

I've had this issue on and off lately too, and noticed the metal contacts on the key pellet looked kind of dull and discolored. I took a pencil eraser and carefully cleaned the pellet contacts and it seems to be good again.

Try this simple tip and see if it helps or not.

I bought a convertible Vette back in 86....it was the 1st yr they had the chip in the key if I remember correctly....car wouldnt start sometimes....after many trips to the shop I was told to place the key on the ground to, well, ground it....seems it would build of static...

I would think they have fixed that problem by now but anyway...

Most of the time this issue happens, its the fault of the stater solenoid. They are known to fail and cause this issue. Happened to my 02 ZO6. I just changed the solenoid and problem was solved. If you tap the starter and the car cranks, thats proof positive the solenoid is hosed

It can be caused by other components but, instead of throwing cash and parts at the issue, its best to use a volt meter and figure out if your getting 12 VDC to the solenoid and if your not, figure out whats not allowing it to get there. Heres a schematic that has all the components involved in starting your engine:

Attachment 48153350

The THEFT DETERRENT RELAY is a good place to start testing. The purple solenoid wire should have 12 VDC on it when you crank the engine.

Mash the clutch pedal all the way to the floor. :D

:leaving:

Try this: When you have the NO START issue, turn and hold the key to START and while your holding it in start, pump the CLUTCH Peddle on and off the clutch safety switch. When you do that you will hear the Theft Deterrent Relay in the passengers foot well click. That proves all the components up to and including the relay coil is good.

Heres a picture of the relay:

Attachment 48153345


Its the relay with FOUR wires. Yellow, Yellow/Black, Red and PURPLE

If it was really the starter solenoid, then would the "Security" light on the dash be blinking? Correct me if I'm wrong, but any time the "Security" light is blinking after a no-start (ie, no cranking at all), then it something related to the PASS key system and there should be related DTCs set.

The OP did not state anything about a flashing security light, which is why everyone is guessing......until he posts his codes.

my code is 40- BCM 01 will that make the C5 not to start???????

Agreed the OP needs to tell us if the "Security" light is flashing or not AND what DTCs he is seeing.

But, the response I posted about Bill's info was a general question asking that if it really was a starter solenoid problem, that there would be no "Security" light showing on the dash or any DTCs set ... I wanted to clarify if that was true or not.

In other words, for anyone having this "no-start" issue, if there is no Security light or no DTCs, THEN the focus would be on the starter solenoid and not something related to the PASS key or security system.

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!!

GUYS THANKS FOR ALL THE INPUT! So here are my codes. I am headed to go watch the game but soon as I get back I am going to read all these responses.

10-PCM P0153 H
P0171 H
P0174 H

28-TCS C1288 H


40-BCM B2527 H C

60-IPC U1160 H

99-HVAC B0361 H

AO-LDCM B2282 H
U1064 H

A1-RDCM B2284 H
B2283 H
B2285 H
B2265 H
U1064 H

Nothing code wise would have caused the problem that your having. My recommendation would be to clear ALL the DTC and see what comes back even though there not part of the issue. You seem to have other issues.

Clear all the DTCs and monitor.

You need to connect a volt meter to the PURPLE wire on the relay. When the issue happens, read the voltage on that wire and see if it reads 12 VDC (Battery Voltage) I you do, the solenoid or connections on the solenoid are bad.

BC

OP,

You have BC helping you,,,,you are in good hands!:thumbs:

Alright I went out today and purchased a volt meter to perform this test the next time I have a "No Start". Soon as I do, I will report back here!

Thanks for the help :) ;)

I've got a question for the experts on the thief deterrent system.

If the key pellet is not read correctly due to the key or ignition switch, will the yellow "Security" light on the dash start to blink when the key is turned to the ON position, or does the key have to go to the START (engine crank) position?

I'm assuming that if the key is turned to the ON position without cranking the engine, and the Security light goes out, then the key has been read correctly and the BCM/PCM have initialized correctly to allow the engine to crank and start.

Is this correct?

Will i finely got my car to start repin the new cylinder plug the vat put everything to together and she start it . But for some reason the old cylinder didn't not work i don't know whether is the cap of the vat that came off the cylinder or what.But thank GOD it star-it

Does anyone know the answer to my question above?

http://farm6.static.flickr.com/5094/...d7604d7b_b.jpg
http://farm6.static.flickr.com/5257/...5703a9c7_b.jpg