Car problems--won't start, help?

[Peanut]

All of a sudden my electronic key to my VW Rabbit '08 isn't working. Overnight it happened. Today I had the key battery changed but when I tried it again it still didn't work. Doors won't open except manually, and car won't start. Any ideas about what the problem might be or how to diagnose? Could my car battery be dead?

My friend suggested having a mechanic come look at it. Should it be an imports specialist? I hate to have to tow it to the dealer... Ugh.

[Ego]

Yeah, could be a dead battery. It could also be corroded battery terminals. Relatively easy fix. Open the hood and try this.

https://www.youtube.com/watch?v=h736fkkKjAE

Before removing the terminals you could jiggle the wires a bit then see if the doors open when you click the key. Be careful of the red (+) terminal. Only touch the rubber part of the wire. Often the corrosion makes it so that the terminal is not touching the battery post.

A few things to look for....

[Riggerjack]

Google says vw has an "immobilizer" with reprogramming directions. I'm on my phone, so I can't link. In any case, Google vw key fob troubleshooting.

Good luck.

[Peanut]

It's not a new key, so there shouldn't be a programming issue, I think. And it all started before the new battery.

I just went back to the car again. I think it must be a battery or electrical issue, right? The overhead lights don't come on when I push the switch. Sorry to be such a moron.

Thanks for the video, I'll spend some time looking under the hood when it's light out. I'm also parked on the street which is not great.

[JL13]

"Car won't start" does not mean anything. Does it crank but won't fire? Does the solenoid click but won't crank. You need to be much much more descriptive.

[IlliniDave]

Not familiar with VWs, but if the lights won't come on, for most cars that would signify a dead battery. Batteries have a finite service life so this wouldn't be unusual. Often a towing service can replace your battery or at least help you jump start the car so you can drive it somewhere to get a new battery.

[henrik]

How long since you last used the car (for more than a few minutes) before this happened?
Is it possible that you left on the headlights or an overhead lamp in the car? Either of these will drain a battery pretty quickly.

If the battery is simply drained and not dead, jumpstarting is usually easiest. Maybe a neighbour has the cables?
http://www.dummies.com/how-to/content/h ... a-car.html

Edit: if you do successfully jump start the car, make sure you drive it for a while (at least 20-30 min) to give the alternator some time to charge the battery.

[vexed87]

My toyota yaris wouldn't start when the key battery died, to compound this, it leaked all other the terminal. Did you check the key for battery corrosion, could your battery terminals be gunked up?

You may have got a dud battery, does the key have a red light that flashes when the buttons are pressed, is this working?

[Sclass]

Let's back up. When did this start? When you played with your remote. Does the car crank? The Honda immobilized system will allow the engine to turn over when you turn the key, but the engine won't start.

I don't think the immobilized chip in an 08 rabbit needs coin cell battery power...but I'm not familiar with that particular car. It's self powered RFID. This would actually be pretty dumb because if your remote doesn't work, you won't be able to manually get in the car and start it if your remote battery goes bad which it inevitably will

I will make a wild guess. Did you change the battery yourself? When you opened the remote button enclosure did anything fall out? On some remotes the immobilizer RFID chip pops out quite easily when you open the enclosure. It makes it easier to change the key head and rubber buttons when they get tired. If the little rectangular chip fell out when you did your coin cell swap your car will crank but not start.

Just a wild guess.

Edit- DOh! like usual ima tard and didn't read your post correctly. I thought you changed your remote battery then it happened. Forget my wild guess. If your main 12v battery is bad, your remote won't open the doors regardless of a new remote battery. Check your 12v(big) battery. Do what ego said.

[cmonkey]

I had an issue where I would intermittently lose all power if the car went over bumps or such. Eventually wouldn't start at all, no power. Starter wouldn't even click. Turned out to be the negative connection to the body of the car was corroded. A light sand and back to normal.

[Toska2]

I think its a dead car battery too. Also check the ground cables from the battery and engine and the main cables from the starter. I had the starter cables short out and shut the engine off.

[Peanut]

Thank you all so much for the tips. I think we need to either test the battery ourselves or try to get a jump. I hope that's all it is.

To clarify a couple things-- yes the red light on the key flashes when I try to open the door. I had the key battery changed at a dealer service dept.

When I turn the key in the ignition absolutely nothing happens.

I haven't left the headlights or anything on recently that I can recall. It's weird to me that the battery would just die, but this is a Volkswagen I guess. Car's 8 yrs old with 55k miles. I drive it a few times a week for 15 min at a time, and had taken it out just the day before yesterday. I'll see if I can decipher anything staring at the engine.

[JL13]

For short trips (15 minutes) a battery would do well to last 3 years. A jump should sort you out.

[JL13]

er, a jump should sort you out enough to get it started and limp to autozone/wallyworld for a new battery

[Ego]

If it's a stick (manual transmission) you can push start it.

https://www.youtube.com/watch?v=1pj4GY_7q8w

[JL13]

@ego if the battery is totally dead that won't work. You need enough juice to power on the computer/fuel pump etc

[Dragline]

Now what is the over/under on Peanut driving a manual tranny 2008 VW? I put it at 50-1 against.

If it is the battery, most autoparts chain stores will install one for free while you wait. But check on line or call before you go. If the battery is several years old, I think I would replace it anyway. I just had the same issue with an '09 Scion that had white corrosion bubbling out of the battery.

[Ego]

@ego if the battery is totally dead that won't work. You need enough juice to power on the computer/fuel pump etc

Huh? The alternator provides the juice.

I'd say it's more like 2 to 1, auto to manual since Peanut is not US based.... I think.

I like the idea of taking bets on this as I'm still betting on corrosion.

[Sclass]

Try honking the horn or turning on the headlights. Short of a voltmeter you can get a seat of the pants estimate of battery power by listening for a loud blare or an anemic beep. Check brightness of headlights. Shake wiring harnesses in ego's diagram shown above if your lights are dim and see if they get brighter.

You get the picture.

Corrosion is a good bet. Our 2012 Accord had a battery harness that was almost rotted through by an acid leak after two years. The connection was made out of sheet copper formed into a loop. It looked like Swiss cheese and broke as I shook it.

[JL13]

@Ego We're getting really technical here, but an alternator doesn't charge just by spinning. The part that spins (rotor) has to generate a magnetic field that passes through the windings on the outside of the alternator (how the electricity is generated. The rotor is an electromagnet - it must be powered on in the first place or no magnetic field exists. It is turned on my a computer - either in the engine computer or a smaller computer attached to the alternator know as a voltage regulator.

So no battery power = no electromagnet = no power generation by alternator.