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View Full Version : Let me introduce you to "Battery Voodoo"



AudiC7Owners
02-20-2019, 06:52 PM
So, I don't know if any of you know about this trick, but I learned it from my friend who is a tech at our local Audi Dealership.

Back Story: This past weekend, I unplugged my battery as a precaution when removing my front bumper to swap in my RS grille. After putting it all back together and driving around a bit I started experiencing some strange things with the car.

-Audi Gremlin #1: The day after the install, I started my car and it was vibrating quite violently and my EPC light was on... almost like having a completely busted motor mount, or having a wicked cylinder misfire. The lower the RPMs the worse it got. I drove it for about ten mins to get breakfast. After breakfast I came back out and started it up... Car ran like normal from there on out.

-Audi Gremlin #2: A couple days after that my Climatronic started acting up. The passenger side Temperature control would pop up on my MMI as if someone touched the control knob, but obviously no one did. After that, the backlighting on my climatronic just shut off. Everything still ran normally, and I could use the buttons to turn it off or adjust my heated seats, but the knobs didn't work at all to adjust temp/fan/blower location. This happened two days in a row.

The Diagnosis: I contacted my friend who works at Audi, and explained the issue. We met up and ran a Vag-Com scan which showed us that the car was only registering .17 volts from the battery. That's not enough to power the dash lights, let alone allow the car to run. This is something my friend has seen and he explained to me that they are seeing lots of battery issues with newer audis where something happens and the car gets stuck on a certain channel and thinks it's not getting enough power to certain systems.

The Fix: My buddy proceeded to perform what he called "Battery Voodoo". He opened the trunk, and disconnected the battery cables from the battery. He then touched the two ends of the battery cables to one another and held them together for a minute. He says you can do this for up to 5 minutes if need be. After that we hooked them back up to the battery and turned the car on. All the climatronic lights came back on! I didn't have another issue with it the drive home.

For those with aftermarket stereos:

If you have an aftermarket Audio System, with a Capacitor, DO NOT do this unless you are using a resistance and know what you are doing.


He also explained to me that I'd be surprised at how many electrical gremlins this process will fix. I hope this may help someone else in the future! Before you take your car to a shop, try this trick and see if it resolves your issue.

xXNateXx
02-21-2019, 04:04 AM
Nice, I’ll kept that in mind.
By touching the two leads together you discharge an capacitors that are holding charged energy in the vehicle.


Sent from my iPhone

bobontheroad
02-21-2019, 06:57 AM
nice share, thx...

AudBoost
02-21-2019, 07:47 AM
Good info!! Thanks for sharing

AudiC7Owners
02-21-2019, 08:45 AM
Nice, I’ll kept that in mind.
By touching the two leads together you discharge an capacitors that are holding charged energy in the vehicle.


Sent from my iPhone

There's the scientific answer I was looking for!


nice share, thx...


Good info!! Thanks for sharing

For sure!

RAF_S7
02-21-2019, 09:38 AM
By touching the two leads together you discharge the capacitors that are holding charged energy in the vehicle.


For those of you who went to tech school, have you ever shorted the terminals on a fully charge capacitor? [o_o]

wwhan
02-21-2019, 09:47 AM
For those of you who went to tech school, have you ever shorted the terminals on a fully charge capacitor? [o_o]

I have done this many times, the results depend on the capacitance, stored charge ESR, cap Inductance and stored voltage. The series resistance and inductance limit the peak current.

dudley123
02-21-2019, 01:01 PM
good way to learn how to weld!

Joe'sS6
02-25-2019, 06:23 AM
If you have an aftermarket Audio System, with a Capacitor, DO NOT do this unless you are using a resistance and know what you are doing.

AudiC7Owners
02-25-2019, 06:58 AM
If you have an aftermarket Audio System, with a Capacitor, DO NOT do this unless you are using a resistance and know what you are doing.

I'll add that to the original post.