Can a Bad Battery Cause Electrical Issues?

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Nick1994

Nick1994

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Lately every once in a while I notice my car cranks a little bit slower than normal, especially if it sits for a day without being driven. It's got a dealer battery that's 22 months old. Dealer batteries are highly recommended for the TDIs because of the power it takes to start them. My commute is 50-55 miles round trip everyday and I took it for an extra 15 miles today on the highway and O'Reillys tested my battery and it said its a bad battery, and was 12.58 volts. Alternator test passed. It then cranked REALLY slow and wouldn't start and I had to jump start it.

This morning on the freeway the airbag light came on on the dash along with the fasten seatbelt light and chime and wouldn't go off unless I fastened the passenger seatbelt (nothing on the seat or anybody riding with me). Connections look good under the seat and after turning the car off and back on the fasten seatbelt light works perfect. Airbag light is still on and won't go off. It has the side airbags in the seats and heated leather seats if that makes a difference.

I'm thinking this might have to do with the bad battery. About 5 years ago it did this same thing and it was some kind of seat belt sensor, so maybe that's it.

I'm taking it to the dealer tomorrow for a new battery and am hopeful the airbag light goes off.

So is it possible for a bad battery to do weird stuff like this to the car's electrical?
 
My 07 MDX had the following occur in first month of ownership:

Check engine light
SH-AWD system disable due to error
Stability control randomly shutting down
Air bag system shutdown in side ones(low power-hint!)
Automatic climate control show error on screen
Nav and radio reset
Power window "lose" its programming so it would not longer go down. Had to look up reprogam.

I was quite scared I bought a lemon although cheap. A dealer I called in desperation for service nicely told me to try a new battery first since overbooked and that is what they do
smile.gif
It worked with $120 Walmart batter and 78k-130k not a single issue electrical or mechanical! The problem battery was only 2yrs old and 2nd replacment since new.
 
yes, but with that decent commute its fairly odd for a battery to die in 2 years.

Do you listen to the radio with the engine off? or anything similar?

also its over 10 years old now and VW are somewhat notorious for having electrical issues. So there is possibly more to this story, bad grounds etc.
 
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Originally Posted By: Rand
yes, but with that decent commute its fairly odd for a battery to die in 2 years.

Do you listen to the radio with the engine off? or anything similar?

also its over 10 years old now and VW are somewhat notorious for having electrical issues. So there is possibly more to this story, bad grounds etc.
It's eaten through batteries every 2 years almost like clockwork since new. Batteries don't last in Phoenix, I've only ever heard of a battery lasting longer than 2 1/2 years once and it was a vehicle not used for 7 months over the summer every year. Nobody's batteries last out here, especially in this diesel. It once got the top of the line O'Reilly's battery years and years ago and it destroyed that thing in 8 months, it just couldn't handle this car lol. Quite common for the TDIs. It luckily hasn't (hopefully not yet) been an electrical nightmare like the typical VW and has been really reliable. I do listen to the radio without the car on in the morning before class for about 30 minutes, but it's not loud and haven't had a problem with other cars doing this.
 
Sure, it might be the battery, heat kills batteries fast... but, once running, the battery is not powering the electrical system, the alternator is. Seems strange that the glitches would occur while driving. And listening to the radio does drain the battery, especially if the key is in the run position vs acc. position... been there, done that, needed a boost... and a new battery shortly after.

Or, maybe the notorious VW electrical gremlins are showing their smiling faces ...

But start with cheap stuff first...
 
Battery could definitely be a problem

I'd have it tested/replaced, and shine up those terminals

This also being said, its a VAG product, electrical problems aren't to be unexpected.
 
The battery tested bad - so you need to start there.

Replace the battery, then proceed with the factory troubleshooting procedure for the airbag light. At this point, anything's a guess.
 
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It sure could but I'm surprised (but not that surprised) that nonessential stuff like the airbag controller can't just self-induce comas during cranking if they don't like low voltage.

Especially on a diesel that takes a good jolt to get going.

You know the dealer or anyone else won't touch it until the battery's happy, so pay up.
 
Yes, heat kills batteries. If you want to save your battery, do a remote trunk relocation, to get it out of the engine bay. Then buy a high end pure lead AGM battery like Odyssey battery, or Die-Hard Platinum AGMs (re-branded Odyssey). That should be clean, safe, and last you 10 years or more.

If you could keep a battery at sub zero temps for it's whole life, it would last 20 years, no joke.
 
If you want the best bang for the buck, and something alot more heat resistant than your typical flooded battery....I HIGHLY recommend that you go to Sam's Club and get the Duracell AGM battery. These are rebadged Deka's from East Penn. The best battery out there, many with a lot of experience think.

I always get the biggest battery that will fit in the battery box/tray. In a car, I always get the high CCA's that I can fit in the battery box. For my boats, it's always the highest reserve minutes.

Trust me, these Duracell's AGM's are the best battery you can buy.
 
Definitely possible. My Dakota started acting strangely, just out of warranty, of course, where I'd shut off the ignition yet the radio would stay powered. The truck doesn't have the "retained power" on it where the accessories will stay on unil you open the door like my Cobalt has, so I assumed the worst and figured I'd have to pay for someone to trouble shoot the electrical system. The dealer started with the battery, said it tested "borderline" so I replaced it and no problems after that.
 
Best battery is battery with longest warranty. Find yourself a battery with 3 year warranty ( there's few manufacturer on offer here so should be similar or better in US), and let them take the expenses.
And yes, faulty battery will interfere with car's electronics so change it ASAP.
 
I had a battery go bad in my Cherokee. Voltage wasn't that low (somewhere around 11). It would crank and crank and crank before starting. When it did start, it wouldn't idle.

Cranked at it's normal (slow) speed.

I was going to replace the crankshaft sensor, played around with some other stuff. It was suggested to change the battery and ... it fixed it.
 
Are you positive the connections are clean and tight? Could cause all the issues you're experiencing, including the failed test.
 
When the battery starts going bad on my 2000 Jetta (BTW the most reliable car I have ever owned) it gets weird electrical problems. Touch the brakes or put the turn signal on on the highway and the engine will momentarily shut off. Scared the [censored] out of me the first time it happened. Replaced the battery and the problem went away.
 
You should get one of those plug into the lighter voltage monitor. I can't see how you would have electrical problems unless the battery was so bad the alternator could not maintain at least 10.5V. At that point the relays start dropping out and your engine control relay cycles. This also causes some warning lights to start to cycle.

My experience is if the alternator when the car is running cannot maintain 13.5V I better look for the reason because it will die soon.
 
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