My car won't start! Sometimes!

August 24, 2012 4:58 PM

I know you're not my mechanic, but are you a mechanic? Because I have a very strange electrical problem with my Jetta that I can't begin to troubleshoot.

My wife and I have a 2002 Jetta - the 1.8T 4DR sedan, automatic transmission and gasoline engine. It has 77,000 miles on it and so far has run like a champ, with nothing but routine maintenance. We just got back from a road trip, and on that trip a very strange thing started to happen. As we were leaving town, the car started up just fine, we drove to the grocery store for some supplies, shut down the engine, and once again after our shopping the car started up just fine. Then we stopped at a gas station less than a mile away, got gas, and when I got back into the car and turned the key....nothing.

No grinding, like a dead/dying battery; no false starts like a mechanical problem, nothin'. Utter silence. Pretty much all the dashboard warning lights came on, but the engine didn't even try to turn over. About three attempts later, after removing and reinserting the key, opening and closing the door, and panicking somewhat (can you tell I'm not a car person?), the car started right up and ran fine. This happened twice more in our six hour drive today.

Other strange symptoms:

- During these episodes, the brake pedal wouldn't depress, which I discovered when trying to shift into neutral to try to start it from there in case that might help
- The car wouldn't shift into neutral, because the brake pedal wouldn't depress
- Even when the key was out of the ignition, the electric windows opened and closed as if the car was running or the key were in the ignition with the engine off

It seems to me like the car might have thought it was still on - like it didn't shut down properly or something? The only things that have changed on the car in the last few months are a couple blown fuses that were replaced (one for the climate control panel lights, one for the cigarette lighter), otherwise the car has never had a serious issue and hasn't really been modified in any way. The battery is about three years old-ish, and I'm not enough of a car guy to know whether that is old enough to need replacement and could be causing this.

Googling didn't really turn up much that would help on this specific issue, so I'm turning to the hivemind - have any Jetta owners out there experienced anything like this? What did you do about it?

I'm going to go to a mechanic at some point, but I want to go in with more than "my car won't start sometimes and it's really weird" because I'm the guy that would take the car in, only to have it start fine 20 times in a row before the mechanic sent me home, thinking I was insane.

posted by pdb to travel & transportation (17 answers total)

I'm going to go to a mechanic at some point, but I want to go in with more than "my car won't start sometimes and it's really weird" because I'm the guy that would take the car in, only to have it start fine 20 times in a row before the mechanic sent me home, thinking I was insane.

I'm not a mechanic, but I am a software engineer, and intermittent problems are common in software. It seems to me that you've got a good handle on what is happening when the problem does occur. I also recall VW people mentioning that electrical issues are not uncommon in the last few generations of VW products.

You should go to your mechanic and tell them what you've written above.

It sounds like some component in the electrical system is just on the edge of failing. It probably isn't a plug, because automotive plugs are usually designed to be ultra robust. More likely it is some other component that is failing due to age or vibration or something like that.
posted by b1tr0t at 5:07 PM on August 24, 2012

Next time, give the steering wheel a pull to the right and left.
posted by BozoBurgerBonanza at 5:07 PM on August 24, 2012

I should add, you can try turning the key at the same time. The steering wheel locking up in Volkswagens is pretty common, you can search around the Internet for lots of advice if you search on "Jetta steering wheel locked" for example.
posted by BozoBurgerBonanza at 5:19 PM on August 24, 2012

My Honda had this issue. It was a connection to one of the battery terminals. I wiggle the connection, and it starts up. Before figuring that out, we blamed the starter motor, but replacing that didn't help. I'd try checking the electrical connections to the starter motor and battery, as well as the starter motor itself.
posted by backwards guitar at 5:20 PM on August 24, 2012 [2 favorites]

My Honda had this issue. It was a connection to one of the battery terminals. I wiggle the connection, and it starts up.

Agreed. Try this first, then check grounds, then check connections to starter. Next, check neutral safety switch connections. Third, possibly ignition switch.

The brakes would depress if you pushed hard enough. They are just very hard to push when the engine is not running. You should get a feel for this in general in case you'd have to brake if the engine stalled on you.
posted by gjc at 5:34 PM on August 24, 2012 [1 favorite]

Just to add to backwards guitar's comment: often, the negative battery cable can become corroded -- at the terminal, at the frame connection, or along its length. The corrosion may not be visible, but it causes significant resistance within the cable, and this prevents the full power of the battery from being delivered to the starter motor. This can cause problems like yours. It might not be the cause in this case, but if this were my car that would be the very first thing I'd check. It doesn't have to be corroded enough to prevent all power from flowing through the cable, just from allowing full power from being delivered through the cable.
posted by mosk at 5:36 PM on August 24, 2012

I have a 1998 Jetta. When I accidentally arm the alarm (stock), it behaves exactly like this.
posted by ApathyGirl at 7:00 PM on August 24, 2012 [1 favorite]

It seems to me like the car might have thought it was still on

This is no software glitch - that just will not happen. The car knows the engine is not running because there is no crank sender pulse (ie the engine is not turning). This is a relatively simple and common issue, I'd guess, it just freaked you out. Any thought processes that consider the car 'not shutting down properly' are the ones that will get you looked at like a nutter at a garage. It's not running Windows...

- During these episodes, the brake pedal wouldn't depress, which I discovered when trying to shift into neutral to try to start it from there in case that might help

Normal. No engine means no power/vacuum assist.

- The car wouldn't shift into neutral, because the brake pedal wouldn't depress
Not so normal - you only have to press the pedal enough to activate the brake light switch to disable the neutral lock. How hard were you pressing?

- Even when the key was out of the ignition, the electric windows opened and closed as if the car was running or the key were in the ignition with the engine off


Normal, you've just never noticed. If you'd opened and closed the driver's door this behaviour would have stopped. It's so you can open your windows (I think it is timed as well) after you have sat in the car after turning the engine off.

It is one of the following:

1: Loose or corroded connection to the starter motor

2: Loose or corroded connection to the battery

3: Loose or corroded connection on one of the earth points.

4: (as mentioned) the immobiliser is being armed somehow. This is the only place where something weird could be happening. Perhaps a key issue or ignition switch glitch. But it could be this. Is there a flashing red/other colour light for your immobiliser? Check your manual and if there is and you can replicate the symptoms see if the light is on at the same time.

I'd be tempted to replicate the symptoms or I'd just take it to the garage and say "I have a weird intermittent not-starting issue. No cranking, nothing, and it is perfectly fine most of the time". You will not be, by any means, the first to take an intermittent fault to a garage for it to be fine no matter how long they have it. For that reason I always drive my cars with failures until the point the failure is repeatable before I even bother trying to diagnose it half the time. Intermittent faults are probably the single biggest hate for mechanics.
posted by Brockles at 7:52 PM on August 24, 2012 [2 favorites]

Just some ideas for you: Right around the time my 2000 Jetta started doing something similar, the battery cracked open and smoke started pouring out. Similar mileage point too. Take it to an Autozone and ask them to check it out. They usually can for free. I know it doesn't make sense logically due to having the key out of the ignition, etc. The only satisfying answer I got was from my manager, a former mechanic, that German cars have all kinds of electrical problems and stuff like this is normal for them. Sorry I don't know more than that.

I also had the brake sensor fail at one point. That was so annoying. The car started but I couldn't get it out of park because it didn't sense that the brake was depressed. If I recall correctly, that came in spurts prior to it failing outright. It's another electrical problem - the mechanics were fine (engine started, etc.). Part of life with a German car apparently, thought it was made in Mexico I think.

The car was a jalopy for me though. It had multiple things wrong with it at the same time so isolating the causes of symptoms was difficult.
posted by jwells at 7:58 PM on August 24, 2012

I'm pretty sure I had this exact same problem on our 2002 Jetta that we just traded in. If memory serves, I recall thinking it couldn't be the battery because of the same symptoms you describe, but in fact when we took it in I think it was battery-related. Unfortunately I don't have our service records anymore so I can't be more specific.
posted by DiscourseMarker at 9:30 PM on August 24, 2012

This sounds like a bad starter.
posted by thebigdeadwaltz at 9:54 PM on August 24, 2012

You could try cleaning the battery terminal and cable connections with a steel brush or steel wool and make sure they are tight. My wife's old Malibu also had a similar problem with the anti-theft device. I'm not sure if the Jetta has one, but if so it may be malfunctioning. Could be as simple as the angle of pressure you have on your key between the car starting or not.
posted by Yorrick at 11:54 PM on August 24, 2012

Brockles has it. It sounds like a grounding issue to me.
posted by Chutzler at 8:43 AM on August 25, 2012

Thanks all. A quick removal of the battery cover this morning revealed a whole lot of corrosion on the positive terminal - like I had to scrape off the pile of corrosion to get to the terminal to disconnect it - so I disconnected the battery and cleaned the terminals with baking soda and hopefully that will help. If not, I at least now have more info to arm myself with at the mechanic if I need to go.
posted by pdb at 10:46 AM on August 25, 2012

I just went through this with my 1999 Passat wagon.


Ended up just being a low-voltage battery. Just replaced the battery!
posted by sneakyalien at 12:56 PM on August 25, 2012

It also could be a neutral safety switch which prevents starting the engine in gear other than neutral or park.

Next time it happens try wiggling the shifter or move it across the range and try it in "N" or "P"

Or, reminding me my wife's Passat, and other VWs, which REQUIRE you pressing the brake to start the car, maybe your brake light switch is bad, which would explain not able to shift out of park and starting the car. Next time this happens tap on the brake and see if it helps, but it could stop working at all over time (same with neutral safety switch)
posted by AdamG8GXP at 10:49 AM on August 30, 2012

That's a really good point, actually. This may be as simple as a safety switch (brake or clutch).
posted by Brockles at 11:07 AM on August 30, 2012