Hello,
I drive to location - get out of the car - go inside store - return to the car - may have been only a few minutes or I may have been a hour or more. I returned to the car with same results. This has happened about 4 times now in the last year. Yesterday being the last! I open the car door-see that I have no dome lights,put key in ignition - no dash lights-no start-nothing-100% dead.
On my newer car battery I have one of them terminal post ends that you are able to unscrew at the + battery post and it stops all current/power from the battery to the car or if tightened it will power the car. I have this on it because as most - the car will drain the battery if the car sits longer then 2 weeks. I also have had this happen to me before I ever put this on the battery.
My way of "waking" up the car is open the trunk with the key and unscrew the battery post end and then tighten it. I may end up doing this 3 or 4 times and then I will hear the CD player make a noise and then I know that the car has power again."Alive". Before I had this end on the battery I had unhooked the terminal and did the same thing with it. But it had put the car in restricted performance when this first happened.That is another story. One at a time.Also yes then I have to reprogram the windows. Simple enough.
Any ideas what is going on to make the car act as if it has no battery in it at times? I have never or try not to lock the power doors or set the alarm because one time after doing so it did the no start and nothing worse then getting in a car and this going on. So I try not to make it think and just leave it unlocked.

 

That was happening to me when I first got my car. I discovered that disconnecting and the re-connecting the battery brought it back to life. My local dealer couldn't duplicate the problem, but told me there was low voltage in the ignition exciter ring (whatever that is) and they could replace it for a few hundred. I didn't replace it, but kept a wrench in the trunk to do the battery thing whenever I needed to. After reading about hard resets on this forum, I tried that and the problem is (so far) gone for good. The alarm and locks didn't seem to make any difference in my case; they either worked or didn't depending on if the car was dead or not.

 

Thanks for the reply/help/answer. It sounds like the very same issues that I am having from time to time.I had never heard about a hard reset? And the low voltage in the ignition exciter ring? I will have to do some searching and see what I find.
Thank you again! Once again this is a great sight to get help and answers!!

 

You may be a bit disappointed with the 'exciter ring' - it's more boring than it sounds!

Part of the vehicle security system and also known as a 'transponder coil', it surrounds the ignition lock barrel and matches with the chip embedded in the plastic head of the ignition key.

Additional security, the purpose is to stop anyone just cutting a key from starting the car.

The part itself isn't where the cost comes in. The keys and transponder have to be matched and this is a dealer only job or one for avery well equiped indy. As soon as you go that route , the costs mount up. It's not like pairing a key fob which you can do youself.

 

I've helped a couple of guys who have installed the green dial type battery disconnect device to their battery and had subsequent problems with lack of power.

In one experience the device simply didn't clamp down hard enough on the battery post to make good contact. You can check this with a multi-meter easily. (Touch the battery post itself with one lead and the disconnect unit with the other - if there is no reading the connection is bad). The clamping material on the devices I've seen doesn't deform enough to make a good connection to the post; I had to really overtorque the clamp to get a good connection.

I have also experienced poor connectivity within the disconnect device itself - the green dial arrangement was sloppy and when "ON" was not making solid contact 100% of the time.

All in all, my advice would be to drop the cheap disconnect altogether and remove the potential for problems, they are just not high enough quality. Get a battery tender or opt for the high quality battery disconnect used in racing applications.

Hope this helps

 

The part itself isn't where the cost comes in. The keys and transponder have to be matched and this is a dealer only job or one for avery well equiped indy. As soon as you go that route , the costs mount up. It's not like pairing a key fob which you can do youself.[/QUOTE]

A couple questions on this.
When the transponder coil is bad does it just quits working all together or will it be showing signs of it going out like it may be doing now?? "No power".
A way of testing this transponder coil ??
I am thinking if it is the coil that even with my other key I will find the same results.

My brother in law works at a large auto auction here in Fl."VW tech". Some times on the weekends when the key tech is slammed with work my brother in law works with him. I will have to ask him now but I am guessing that the guy is set up to program keys possible?? Or he is not really making the key but has this transponder coil lock sets with him and they change it out? I am just guessing.
I had heard that the keys are $$$ for new cars if you loose them. Guessing now that it is not just the key but the fact that they have to change out the transponder coil also?
I thought somehow in his case that he was able to make just a key for the cars? They deal mostly in cars just a few years old "rental cars/lease returns/etc."and from time to time older cars.

I did not think that my key being from a 2000 was the same set up as the newer keys that cost so much to replace?

 

Hopefully it's not the coil (thanks for the info GGG). My reset has done the trick for over a year now. It involves removing the + battery cable from the battery with the car ignition off and touching the + cable to the - cable. Then with the cables still together, turn the car ignition on and then off. Reconnect the + cable to the battery, reset your windows, and off you go happily ever after (or at least until next time).

 

Last time I had transponder problems was with an XJ saloon doing a similar thing. It was an intermittent fault like you have and not an all out failure.

You say "I am thinking if it is the coil that even with my other key I will find the same results.." Yes, exactly. On the other hand, if you don't get the problem with the other key, it shows coil OK and the key you're using now has a faulty chip. This is one way of testing whether it's key or coil.

I'd be checking this and eliminating all other options before going to the dealer with this. Spurlee has raised doubts about the battery disconnect device and Mike66 reports success with a reset. Get the wrenches out before the $$$!

 

This thread is very helpful: had a scare earlier today when the car electrics appeared to be completely dead. Checked the battery voltage, saw 12.5v which I reckon is low but okay. So after reading this thread, I did a hard reset and the car started without a problem. Took the car for a blast up and down the local motorway: it didn't miss a beat and I had a lot of fun dropping gears in the late Autumn sunshine.

This has come about because I'm doing a lot travelling for work (with hire cars) and the poor beast is only doing short commuter runs. Hence the battery isn't being charged properly. The voltmeter in the dash is registering 13v, which also seems a bit low to me (I'd expect it to read nearer 14v). So I figure a new battery will be needed before the cold weather starts, and/or a new alternator (generator).

But I wanted to say "thanks" to the people who spend time working through these sorts problems with people - this forum is a great knowledge base as a result. Plus a lot of fun, too.
Best wishes, Colin

 

Read the battery voltage with a digital multimeter on the battery terminals...though the voltage gauge can give an indication of whether the alternator is running or not, it is computer damped and it is not accurate enough to diagnose potential problems.

 

Hi.

-If the car electrics are completely dead (no dome lights), it is probably a bad connection from the battery. The fat stranded cable from the positive battery post to the heavy fuses in the trunk has a history of failure and poor connection

-Again, if your dome light doesen't light up when opening the door it has nothing to do with the transponder security system.

-I am not too enthusiastic about aftermarket battery connectors from my experience with leisure boats. If you have to have one, it will have to be high quality.

-Not locking the car will always drain your battery. The car will never go to full sleep when not locked.

-Short trips will not fully charge your battery. Check the age of your battery, they don't last forever.

-An electronic battery charger is a good idea.

 

Both Steve and Oyster are right on the money. Don't believe gauges alone; check with an independent device. Digital VOA meter, IR temp gun, hand-held tach, etc. All handy additions to the toolbox. In your case, 12.6V +/- is a charged battery, most alternators put out about 14.2 or so while the car is charging, and drop to about 13 when the battery is almost charged. If you can hook up a Battery Tender or similar, your battery worries will be gone.