Reset after changing battery

Asked by May 19, 2016 at 04:56 PM about the 2012 Volkswagen Passat

Question type: Maintenance & Repair

2012 VW Passat mu car won't start after replacing
the battery to I have to reset the computer? If so

9 Answers


I don't know anything about VW's but changing the battery should not require a "reset". Try double checking your work - Pos & neg cables hooked up to the right terminals? Wiring connections clean and tight? Battery fully charged? Do your lights illuminate when you turn them on?

4 people found this helpful.

VW immobilizer kicked in. Preventing a start up. check your manual or check back later if you need the procedure.

3 people found this helpful.

the biggest mistake people do with late modal cars is think they can remove the battery with out a back flow of current to keep the computer from wiping it self. when you go to replace or remove a battery you need to attach a tender to the cables to keep the voltage in the car going or else the car forgets all its settings. if you have a blue key symbol on the dash the immobilizer is on and won't allow the car to run. This often results in needing to reprogram your key to your car. ou can try this tho.. put the key to Power ON only and wiat 15minutes. after the time is up turn to power off then try starting the car. this might or might not work.

6 people found this helpful.

Help ME.. My battery died and I changed it. Now da Danggg horn won't shut off.. it's driving me crazy#What do I Do???? Please helo

3 people found this helpful.

disconnect the battery and then find the horn trace the wires till you figure out where the wires are crossed. you likely have a short some where (most shorting issues are at where the wireing cables go threw the fire wall.


If you installed a new battery and the horn blasts continuously then you have installed the battery backwards!! This is extremely dangerous. Turn the battery around and this will solve the problem. The color of the battery cables do not mean a thing in the VW so don't assume red/brownish cable is positive. When the battery is placed correctly, the horn will not turn on. Also note that the replacement of the battery will also trigger other sensors on the dashboard so don't be surprised if other lights come on when you turn your car on.

6 people found this helpful.

By tender do you mean tether or attach a battery charger to maintain current until the new battery is attached? Exp,Builderchick


a tender is a device that maintains the batterys charge if it sits for a period of time or if you need to disconect the battery. so yep :P

1 people found this helpful.

I now understand how to not lose the data. I'm attaching a battery charger (tender) to the proper battery lug. I will then loosen the battery lugs and remove the bad battery.. After installing the new battery, making sure the polarity is correct. I will remove the battery charger and start the Jetta TDI 2006. I am also getting the alternator and belt checked, because the car is so old. Supreme thanks exp.builderchick

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