1slowTA

First off I've searched and didn't find my exact symptoms. My 'vette is an '05 Z51 Coupe with HUD and navigation if that makes a difference. It has 14k miles and I've had it for about 2 months.

Every now and then the FOB wouldn't work on the first try but always on the second or third. This is true for opening the hatch with the FOB or starting the car. Once I had the "No FOB detected, shut off?" but everything worked fine when I got back in an hour later.

Today I leave work and the hatch wouldn't open with the FOB or exterior button, no luck with the driver's door either. I opened the hatch with the key and the alarm went off. I opened the door and put the fob in the glove box slot and got the "No FOB detected" message. This last part really confused me!!!

I tried the glove box slot a few more times, turned the FOB around once, tried another few times with no luck. Then I tried the hatch release button on the FOB and it worked! The car started fine and got me home without the "No FOB, shut off?" message.

I tried the glove box slot with the other FOB and no luck either. So I figure there could be something wrong with the glove box slot (is there another name for this?... GBS?) I tried the relearn step but stopped since both FOBs were already recognized. I'm pretty sure that means the GBS is working, right? I tried the GBS with no battery the FOB thinking there might be some dopey program that made it work with a dead FOB only.

I'm not sure if the main battery has been changed (there are no markings on it, it is a Delco), but the car starts fine when it finds the FOBs. I replaced the FOB battery, but don't see how that would help the GBS issue.

For the record I have no aftermarket parts, no tune yet, nothing plugged into the lighters, and my cell phone battery was dead! Of course onstar wouldn't work with the ignition off.

I bought an extended warranty, but I'm kind of worried that I'll get stranded for a stupid issue. I know the routine for telling the dealers how to do their job, but I'm wondering if there are any key symptoms I should mention or what kind of response I'll get from them.

bearphoto

One of the other fob threads someone stated they had similiar problems to yours, they had new batteries in the fobs but took them out and cleaned the fob contacts as well as both sides of the batteries and their problem was solved.

Apparently the oils on our hands are enough to make the fobs mess up. I have no personal experience with this problem yet with my vettes but this solution has worked for others. Good luck.

CO Lightfoot

Sounds like maybe a weak/dying car battery. Enough juice to sound the alarm but not enough to energize electronics & start the car.

If you have a 6-speed manual, do you put it in "reverse" before shutdown? If not, this will drain your battery.

Short trips and/or infrequent use can also drain the battery. The C6 OEM battery is small and doesn't recover very well from discharges. So, regular use of a good battery tender/maintainer is a wise precaution.

Dead Battery Syndrome (DBS) was a problem for 2005 models. Computer reflash will fix it -- very well-known, so yours has likely been fixed already.

If you replace the battery, make sure it is well-charged -- the C6 charging system is marginal and not-so-good at charging a weak battery.

More than you'll ever want to know about battery issues:
http://forums.corvetteforum.com/c6-c...ocked-out.html

1slowTA

The car is a manual and I follow the directions that pop up in the display every time I shut the car off! It is also a daily driver for my 6 mile commute. It sat over the weekend but was fine Monday, Tuesday, and this morning.

Good point about the updates, I will ask the dealer to give me the newest ones available.

Vette_DD

If bearphoto's suggestion doesn't work, think seriously about replacing the car battery. My 06 starting giving some of the same symptoms as yours.

First, pressing the fob button to unlock the rear hatch quit working. Within days, I got the No Fob Detected message when trying to start the car. Sometimes I had to play with the fob buttons before I could get the driver's door to open.

After about 2 weeks of this, I took it to the dealer and left it all day. They replaced the car battery and that fixed everything. My car is a DD with 35K miles and I'm the original owner, so I was just so sure it wasn't the battery. But that was 2 months ago and everything has been okay since.

1slowTA

I can understand the bad FOB battery and I can also understand the dirty contacts in the FOB. But what I don't understand is why the glove box slot doesn't recognize the FOB when that is when you're supposed to use it... when the battery in the FOB dies!

usraptor

The 'Vette's, especially the '05s have a lot of electrical gremlins. Some times what seems logical, isn't. Like others said, it may be a bad car battery and somehow that is affecting the glove box slot. Good luck and keep us posted as to what you find.

Vette_DD

This is additional evidence that it's probably the car battery. If the fob slot is okay, it should allow the car to start, even if the battery in the fob is missing.

cclive

These are symptoms of a low car battery. Low voltage will cause lots of crazy things and the GBS not recognizing the fob is sure one of them. You are absolutely right that the slot is working right though when it says that both fobs are "known fob". This is not a fob programming issue. A new battery would be a good idea, especially when it is possible that yours is the original.

1slowTA

So the car battery can be good enough to start the car when it feels like it, but NEVER recognize the FOB in the GBS... I guess I've heard crazier things!

JoesC5

GM's engineers spent countless nights and drank many cups of coffee in order to come up with an electrical operating system to keep us(and the car) confused, and to keep them employed next year, solving the problems they created this year.

cclive

Yes...because batteries fail in different ways. One way is a catastrophic failure where it has a surface charge but can't produce the big current to run the starter. Another is where is gradually loses charge voltage but is still intact internally and can still hit the big current. Remember that the starter actually runs at about 9.6 volts, so as long as the battery can still produce a few hundred amps at that voltage, it will turn the starter over. The question at that point is 'will all the electronics give it a chance to do that'. If the system voltage is low, and it causes the fob system to not recognize your fob, then it will never give the battery a chance to try to crank the starter. If you want to try something, try putting a charger on the battery when this issue happens...that increase in system voltage will probably allow the system to recognize you. But I think a new $80 battery is probably a simpler and easier thing to try.

CO Lightfoot

Like, a "Service Column Lock" message? Don't believe every message you see.

I've read just about every battery-related thread... you'd be amazed at the problems caused by a weak car battery.

c1vettes

Many of us have this FOB issue and other than cleaning the contacts, I have not seen a solution. In your case though, since the car is at least five years old and you have had it only 2 months, the car battery should be considered as the culprit. There should be some markings on the battery denoting when it was produced. If this is the original, you are pushing it anyway. Check this out.

cgrundman

My car is also a 2005. I had the same problems as you. It happened at the dealer when I was having my top painted. They ended up replacing the FOB, and I have had no problems since.

1slowTA

I put a voltmeter on the battery and it came up with a whole 9.6 volts! I know what I'm buying tomorrow.

cclive

Bingo! So your battery is failing in a slow, controlled way rather than the usual catastrophic way. The new battery should fix it all...make sure to let us know how it turns out...

This is good knowledge though because we have had all different kinds of electrical symptoms of a low battery. You just had the fob system go wacky, but many have had 12 different DIC messages, traction control, column lock etc....this is good info for diagnosing other's problems!