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Intermittent No-Start issues/Possible VATS Problem.

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Old 06-27-2012, 08:49 PM
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ZYBORG
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Default Intermittent No-Start issues/Possible VATS Problem.

Hello guys,

Unfortunately here I am asking for some help as I have been experiencing intermittent No-Start issues on my 04 C5 Z06 for a little while now and the issue has gotten worse over time.

It all started when a long time ago while driving I noticed my security light came on and stayed on, without experiencing any symptoms, the next day the light was gone and stayed gone till now.

Fast-forward several months later and last month I offered someone a jump since their battery was dead, once I hookep up the jumper cables my car would not start. I sat there for a little while till it finally decided to start.

Seems like from that point on the car would fail to start every once in a while recurrently and progressively getting worse until yesterday it took me 1.5 hours playing with it for it to start.

Whenever the car fails to start, the "SECURITY" light blinks. There has also been a couple of times that the car starts and the "SECURITY" light stays on.

Here is what I have tried so far: I did the 30 min VATS re-learn proceedure and replaced the TDR with a new one (the old one seemed to have some discoloration at the prongs). Seemed like I had fixed the issue once I replaced the TDR but after several starts it failed once again. The current codes on the car are as follows: 10 PCM P1631 H and 40 BCM B2721 HC.

** I should also note that the car had some water leaks by the passenger door/firewall onto the floor pannel, I thought I corrected the issue. Later down the road I had my heater core go out and leak onto the passenger side as well (this was fixed by the dealer under warranty). **

Next step for me is probably going to be removing the ignition switch and doing a repair/clean up.

Please help, Im stuck and life without my car is sucking!

Last edited by ZYBORG; 06-27-2012 at 09:12 PM.
Old 06-27-2012, 11:53 PM
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ZYBORG
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Originally Posted by 8VETTE7
Are there ANY codes other than the two that you listed. If there are ANY others list them so we have complete info.

In the passenger footwell is there any indication that the BCM (large silver box to the left of the IP fuse box) has gotten wet? Look for water stains and calcium deposits on the aluminum cover that houses the BCM electronics. If the aluminum cover has water stains, have you removed the BCM from the car and taken the BCM board out of the aluminum box and carefully examined it for corrosion? You may need a magnifying glass to see everything. Disconnect the battery BEFORE you start working with the BCM or any of its connectors.

Have you used your backup key for the car and do the same symptoms persist?

Have you cleaned the pellet on your key(s) with the eraser on a pencil?

Have you used contact cleaner and attempted to clean the sensor wire that reads the pellet on the key?
No, at this moment those are the only codes.

From what i can tell at the moment, there is no water marks on the BCM (will look closer). I have not removed it but will remove it and inspect it now.

I have used the back up key and symptoms still persist.

I have not cleaned the pellets on the keys but they dont appear dirty, will try this anyway, although im sure that is not the issue here.

What is "the sensor wire" and where is it? How do i clean it?

Thanks for the input.
Old 06-28-2012, 12:24 AM
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Suprsaiyjinbroli
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Originally Posted by ZYBORG
Hello guys,

Unfortunately here I am asking for some help as I have been experiencing intermittent No-Start issues on my 04 C5 Z06 for a little while now and the issue has gotten worse over time.

It all started when a long time ago while driving I noticed my security light came on and stayed on, without experiencing any symptoms, the next day the light was gone and stayed gone till now.

Fast-forward several months later and last month I offered someone a jump since their battery was dead, once I hookep up the jumper cables my car would not start. I sat there for a little while till it finally decided to start.

Seems like from that point on the car would fail to start every once in a while recurrently and progressively getting worse until yesterday it took me 1.5 hours playing with it for it to start.

Whenever the car fails to start, the "SECURITY" light blinks. There has also been a couple of times that the car starts and the "SECURITY" light stays on.

Here is what I have tried so far: I did the 30 min VATS re-learn proceedure and replaced the TDR with a new one (the old one seemed to have some discoloration at the prongs). Seemed like I had fixed the issue once I replaced the TDR but after several starts it failed once again. The current codes on the car are as follows: 10 PCM P1631 H and 40 BCM B2721 HC.

** I should also note that the car had some water leaks by the passenger door/firewall onto the floor pannel, I thought I corrected the issue. Later down the road I had my heater core go out and leak onto the passenger side as well (this was fixed by the dealer under warranty). **

Next step for me is probably going to be removing the ignition switch and doing a repair/clean up.

Please help, Im stuck and life without my car is sucking!
I ran into a similar issue...notice my highlights above.

Long story short, what caused my issue was that over time the two tabs inside the key hole/tumbler became dirty from use...so it would read sometimes and other times it wouldn't.

Now...I could have cured my ills...for 0 bucks...but hey...such is life, live and learn.

Here is the fix: (BTW, I'm a 02 C5Z) Look at the front of the ignition...the silver "key hole". If you look inside you'll notice two, should be silver...won't be if they're a little dirty...areas where the system reads your key. If you see some dirt in there, lemme know. We can get you fixed for free...if thats the case.

If not...we can get you fixed too, just gonna be more time and some money.

Lemme know, pretty sure I can help you out man.
Old 06-28-2012, 07:57 AM
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ZYBORG
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Originally Posted by Suprsaiyjinbroli
I ran into a similar issue...notice my highlights above.

Long story short, what caused my issue was that over time the two tabs inside the key hole/tumbler became dirty from use...so it would read sometimes and other times it wouldn't.

Now...I could have cured my ills...for 0 bucks...but hey...such is life, live and learn.

Here is the fix: (BTW, I'm a 02 C5Z) Look at the front of the ignition...the silver "key hole". If you look inside you'll notice two, should be silver...won't be if they're a little dirty...areas where the system reads your key. If you see some dirt in there, lemme know. We can get you fixed for free...if thats the case.

If not...we can get you fixed too, just gonna be more time and some money.

Lemme know, pretty sure I can help you out man.
Ok, i will look in there after work today. Lets assume it is dirty in there what should i do? At this point ill try anything. How do you suggest i cure the issue?

Thanks for your help!
Old 06-28-2012, 08:02 AM
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Originally Posted by 8VETTE7
As I mentioned in my post above, disconnect the neg battery cable BEFORE you do anything with the BCM.

The sensor wire I refer to is inside the ignition cylinder. It is a very fine wire that wipes across the pellet on the key to read the value of the resistence and acts on a match to allow the car to be started. On a mismatch the B2721 DTC is set and the PCM refuses fuel delivery and the BCM disables reading the resistance for a period of 3 minutes. So for 3 minutes you are wasting your time trying to start the car after the mismatch.

So, I suggeste cleaning the pellet on the key as well as any oxidation that may be on the sensor wire. An eraser on a pencil will clean the pellet nicely but wipe the pellet with a lint free cloth after cleaning. For the wire in the cylinder, get some electrical contact cleaner in an aerosol container ( Radio Shack has this for certain and you should be able to find it at a well stocked hardware store). Spray some inside the key slot and then insert and remove the key 10 or 12 times wiping off the key between insertions with a clean lint free cloth. Repeat it if you like a second time.

Another thing that can be going on is that the ignition switch (different from the ignition cylinder) may have burnt contacts. Here are some links thanks to Bill Curlee that talk about diagnosing the switch, removing it and cleaning/repairing the contacts:

diagnosis

http://forums.corvetteforum.com/1568186703-post64.html



removal

http://forums.corvetteforum.com/1571067145-post107.html


repair procedure

http://forums.corvetteforum.com/c5-t...ch-repair.html
Thank you very much! I will try this as soon as i get the chance and report back.
Old 06-28-2012, 08:33 PM
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***UPDATE*****

So I went ahead and cleaned the ignition with the electrical contact cleaner and the key to no avail. The car still wont start. I cleared the codes and they came back as P1631 HC and B2721 H.

Here is a question, I have been hearing reading that HP Tuners is able to de-activate the VATS system with a tune and therefor correct the problem. Is there any truth to that?

My next step is probably going to be attempting to clean/fix the ignition switch itself.

Any further info or ideas please dont hesitate, I need all the experience I can get at this time as I am a rookie at this.

Thanks for any further help.

Last edited by ZYBORG; 06-28-2012 at 08:36 PM.
Old 06-28-2012, 11:39 PM
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Originally Posted by ZYBORG
***UPDATE*****

So I went ahead and cleaned the ignition with the electrical contact cleaner and the key to no avail. The car still wont start. I cleared the codes and they came back as P1631 HC and B2721 H.

Here is a question, I have been hearing reading that HP Tuners is able to de-activate the VATS system with a tune and therefor correct the problem. Is there any truth to that?

My next step is probably going to be attempting to clean/fix the ignition switch itself.

Any further info or ideas please dont hesitate, I need all the experience I can get at this time as I am a rookie at this.

Thanks for any further help.
Do the contacts in the ignition looks dirty?

Next step is to pull the ignition out if so.
Old 06-29-2012, 12:04 AM
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The sensor on the ignition lock cylinder might not be reading the pellet all the time. On mine I got up one morning and tried to put the key in the ignition and it wouldn't go in so I forced it and broke it. They do wear out in time. Its not hard to get a new lock cylinder and have it replaced. Theres an easy test but you have to take apart the dash so you can get to the connector. You get a multimeter, set it to resistance and measure across the 2 wires in the connector with the key installed and turned. If you get nothing then the sensor is bad. You should have some resistance depending on what key you have.
Old 06-29-2012, 03:36 PM
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joe Villarreal
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I had the no start problem today thanks to all your answers I sprayed a electrical connector fast drying solution into key hole and cleaned pellet with eraser and my baby started right up also had the security light flashing while trying to start. the result a dirty pellet or ignition switch
Old 06-30-2012, 01:56 PM
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****UPDATE****

So to recap i have changed the TDR, i sprayed electrical contact cleaner on my ignition key hole (even though it looked clean), i cleaned the pellet in both keys and even also inspected the clutch switch and sprayed it with contact cleaner. I also went ahead and tested the ignition switch by testing the volts with a volt meter and everything read 12.5v, the only odd thing i noticed is that it states that i should be checking "BCM 13 fuse 22" but there is no fuse on there and even on the IP legeng it shows that slot 22 is open/no fuse goes there.

I dont know what to do anymore....

PLEASE HELP.
Old 06-30-2012, 02:07 PM
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lucky131969
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Originally Posted by ZYBORG
****UPDATE****

So to recap i have changed the TDR, i sprayed electrical contact cleaner on my ignition key hole (even though it looked clean), i cleaned the pellet in both keys and even also inspected the clutch switch and sprayed it with contact cleaner. I also went ahead and tested the ignition switch by testing the volts with a volt meter and everything read 12.5v, the only odd thing i noticed is that it states that i should be checking "BCM 13 fuse 22" but there is no fuse on there and even on the IP legeng it shows that slot 22 is open/no fuse goes there.

I dont know what to do anymore....

PLEASE HELP.
Not sure I understand your approach, or the parts changing. You clearly have a code for the VATS, and the engine will not crank, as long as the key cannot be read. Possible causes:

1) Bad lock cylinder
2) Bad/dirty pellet on key
3) Bad wiring between lock cylinder and BCM
4) Bad BCM

You first need to read the resistance of the key you have, and record that value. Then, as a previous forum member suggested, you can test the restance at the lock cylinder connector....with the key installed. If you do not want to take apart the console just yet, you can also read the resistance at the BCM connector. Do you have the following:

1) DMM, and the ability to use it?
2) Service manual, or appropriate schematics for your car?
Old 06-30-2012, 02:36 PM
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Originally Posted by 8VETTE7
Has your car ever had a leak that allowed water into the passenger footwell?????

Look at the BCM (silver box to the left of the IP fuse box in the passenger footwell). Do you see any stains on the aluminum box that would indicate that the box has gotten wet???
My car did have water leaks a while ago which i though i fixed, this was over a year ago. I guess i could inspect the BCM... How do i go about taking it off and inspecting and what am i looking for to determine if i need to either clean it or replace it?

Thanks,

Originally Posted by lucky131969
Not sure I understand your approach, or the parts changing. You clearly have a code for the VATS, and the engine will not crank, as long as the key cannot be read. Possible causes:

1) Bad lock cylinder
2) Bad/dirty pellet on key
3) Bad wiring between lock cylinder and BCM
4) Bad BCM

You first need to read the resistance of the key you have, and record that value. Then, as a previous forum member suggested, you can test the restance at the lock cylinder connector....with the key installed. If you do not want to take apart the console just yet, you can also read the resistance at the BCM connector. Do you have the following:

1) DMM, and the ability to use it?
2) Service manual, or appropriate schematics for your car?
Bad lock cylinder: how can i address this? I believe there is a recall for this on the car....?

Bad wiring and/or BCM: not sure about the wiring but im trying to figure out how to take off the BCM to inspect it for water damage/dirt...

Bad or dirty pellet on key: i cleaned the pellet on both of my keys and still no start. I didnt know that the resistor pellet could go bad...

At the moment i have a "Bel MERIT DM 3050" volt meter. I have never really used one but i will have to learn.

I read the resistance on my key pellet and it reads 8.1 how do i check to see if my ignition switch reads this?
Old 06-30-2012, 02:39 PM
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IF YOU WOULDNT MIND I COULD ALSO CALL YOU TO GET BETTER DIRECTIONS AS TO HOW TO DO THIS. Just let me know if this is a easier route to come to a resolution...

Thanks.
Old 06-30-2012, 03:17 PM
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Originally Posted by 8VETTE7
Here is a table of Key resistance and variations from the nominal:



Your measured value does not seem to fit the keys for the C5.

Perhaps you read the meter wrong????
Yeah, im not sure if i used it correctly..

I MEASURED IT AGAIN AND IT READ 3.00 so i think i have key 9.

I made a little VATS resistor bypass that measures the same values as my key... Im thinking about hooking it up to my ignition switch to try to permanently disable the VATS..

Last edited by ZYBORG; 06-30-2012 at 03:32 PM.
Old 06-30-2012, 06:24 PM
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Originally Posted by 8VETTE7
Even if you hook it up to see what (if any) effect it has, it may narrow down the search. Just make certain the resistor is between the values in the table above. There is a black and white wire wrapped around the rubber boot on the key cylinder. There is a plug on the wires from the cylinder. You can connect the resistor setup to the "car" side of the plug (as opposed to the cylinder side of the plug. Then a few test starts to see if it works. If it doesn't work then the problem is on the car side of the plug. ie wiring or BCM.

The reason I asked about the BCM having gotten wet is that there MAY be some corrosion either of the BCM connectors or the BCM board itself that could be creating a problem. If you decide to touch the BCM be certain to disconnect the battery BEFORE removing cables from the BCM or removing the BCM from the car. The electronics on that board are very sensitive.
So here is what I did:

I used my volt meter and set it to 20K (OMHs) it read my key value as 2.96-3.1. I then created a resistor with as close of a value that i could come up with (2.86-3.0). I then spliced the 2 white wires (inside black jacket) that go from the ignition switch to the conector where it conects and then turns into a white/purple and black/white wires. I conected my resistors to the 2 ends of the white wires to make a loop and then conected that to the conector that went to the white/purple and black/white wires. I tried to start the car and nothing.

On a side note: I tried to get a reading off of the spliced ends after I hooked up the resistor bypass pack to the 2 white wires and hooked it up to the conector and I was not able to get a reading, I dont understand.

I am lost at this point.

I am about to try to take out the BCM and inspected but i am not sure how to remove the BCM, all I know is I should disconect the battery.

Last edited by ZYBORG; 06-30-2012 at 06:45 PM.
Old 06-30-2012, 06:41 PM
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Originally Posted by ZYBORG
So here is what I did:

I used my volt meter and set it to 20K (OMHs) it read my key value as 2.96-3.1. I then created a resistor with as close of a value that i could come up with (2.86-3.0). I then spliced the 2 white wires (inside black jacket) that go from the ignition switch to the conector where it conects and then turns into a white/purple and black/white wires. I conected my resistors to the 2 ends of the white wires to make a loop and then conected that to the conector that went to the white/purple and black/white wires. I tried to start the car and nothing.

I am lost at this point.

I am about to try to take out the BCM and inspected but i am not sure how to remove the BCM, all I know is I should disconect the battery.
I'm not in a position to give you a call right now, but you need to step back, and stop going for the easy fix. Hacking up the wiring was unnecessary. All you needed to do, was read the resistance off the lock cylinder connector with the key in. If it was good, you plug it back in, and move on to reading at the BCM connector.
Old 06-30-2012, 07:03 PM
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When my Zee went through the same issue - no starts with a blinking Security light - I measured the key pellet and it measured fine. Also tired the other key which sits in a box, and it wouldn't work either.

Then I looked carefully at the metal ridge on the pellet and it looked kind of grey and tarnished. Used a soft pencil eraser on the metal strip on the pellet to get it nice an shiny. That solved all the starting problems for me. Still worth a try. Not sure your fancy wire operation with a simulated key pellet resistance was a valid test or not. Hard to say without digging into wiring schematics, etc.

If the Security light blinks after the key is turned to the ON position, the BCM is not reading it for some reason.

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Old 06-30-2012, 07:27 PM
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Originally Posted by lucky131969
I'm not in a position to give you a call right now, but you need to step back, and stop going for the easy fix. Hacking up the wiring was unnecessary. All you needed to do, was read the resistance off the lock cylinder connector with the key in. If it was good, you plug it back in, and move on to reading at the BCM connector.
I appreciate your input, i assure you, i do. But im not going for "the easy fix" im going with whatever works and gets my car started and working as it is my daily driver. I believe i asked before i did that how to read the resistance off the lock cylinder connector with the key in and also how to read at the BCM conector. Unfortunately i have yet to receive an answer/easy to follow directions.
Old 06-30-2012, 08:41 PM
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Originally Posted by ZYBORG
I appreciate your input, i assure you, i do. But im not going for "the easy fix" im going with whatever works and gets my car started and working as it is my daily driver. I believe i asked before i did that how to read the resistance off the lock cylinder connector with the key in and also how to read at the BCM conector. Unfortunately i have yet to receive an answer/easy to follow directions.
Reading at the lock cylinder connector, just involves touching the meter leads to the contacts on the connector...with the key in. You should read the same resistance as the key. You never did provide an answer, as to whether you have a service manual.....
Old 07-11-2012, 10:27 PM
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****UPDATE/PROBLEM SOLVED****
===============================

So first off thanks a lot to everyone that threw their input out there while i was trying to figure this thing out but a SPECIAL THANKS GO TO 8VETTE7 FOR GOING ABOVE AND BEYOND TO HELP. Thank you so much and like I said to you before, if there is ever a way I can help you please let me know as it would be my pleasure.

Well, so here it is...

After much troubleshooting it came down to having a battery on its way out while at the same time a bad ignition switch. I also cleaned the conectors at the BCM (that might have helped too).

Again much thanks to everyone!


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