GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

Battery disconnected, now have malfunctions

AsymmetricKururin

New member
Location
Canada
Car(s)
2017 Golf R
I have a MK7 Golf with low mileage, no prior electrical or electronic component issues.

While attempting to install a battery maintainer, the negative battery cable popped off the post and caused a spark when it touched back down. I decided to not risk other problems while I was fighting with the leads on the battery maintainer so I disconnected both battery cables and covered the battery with a heavy cloth until the leads and cables were secured.

Once I reconnected the battery and started the ignition I had a bunch of Malfunction Indication Lights appear in the instrument cluster. I scanned all the control modules with my VCDS and found that now I have errors on these modules:

01 (Engine) --> multiple databus errors concerning the accelerator and brake fault statuses

03 (ABS Brakes) --> steering angle sensor

10 (park/steer assist) --> 2 databuses received an error message

13 (Auto Dist. Reg) --> 4 databus error or implausible messages

3C (lane change) --> 1 databus error message

44 (Steering assist) --> steering angle sensor not initialized

A5 (Frt. Sens. Drv. Assist). --> databus received error message

Does anyone know from personal experience with a Mk7 VW, not mere speculation if these messages are likely to go away on their own if I take a 20 minute drive to allow the car to re-learn or re-calibrate something? Or do these control modules need to be manually re-initialized due to the temporary loss of power? Or does this combination of DTCs indicate that the spark on the battery terminal actually damaged some of the control modules?
 

Raguvian

Autocross Champion
Location
Bay Area, CA
Car(s)
2019 GSW 4MO 6MT
All the lights on my dashboard were lit up when I reinstalled my battery. They went away by the time I pulled out of my parking lot.
 

George Ab

Drag Racing Champion
Location
Pacific NW
From my personal experience. If you disconnect the battery after 10 to 15 minutes of the car being on, all failures will reset about 30 seconds after starting car. If the battery is disconnected withing the first ten minutes, I get a communication error, engine light will go on and stay on. You then need to reset fault code/s with VCDS.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
From my personal experience. If you disconnect the battery after 10 to 15 minutes of the car being on, all failures will reset about 30 seconds after starting car. If the battery is disconnected withing the first ten minutes, I get a communication error, engine light will go on and stay on. You then need to reset fault code/s with VCDS.

You can reset fault codes with a cheap OBD2 reader and the Torque app. No need for VCDS for just resetting codes. VCDS is great for lots of things but I didn't want other people to think that you have to have it to clear codes.
 

Carlosfandang0

Autocross Newbie
Location
UK
Car(s)
2016 3Dr GTi DSG CSG
I recently disconnected the battery when I removed my steering wheel, I got all of the faults and lights you described but they do all go and everything goes back to normal after a bit of driving, I did however still have a couple of faults logged (no dash lights) so had to clear them with VCDS, they didn’t cause any problems however and could have been left logged until such time they could be cleared, at a shop on your next service for example.
 

YamR1rider

Drag Racing Champion
Location
Tampa, FL
Car(s)
2017 GTI Sport DSG
What everyone else said, just drive it, the lights will go out, usually within a few feet. The spark putting your lead back on isn't an issue -they do that.

Also you will have to set your clock.
 

Carlosfandang0

Autocross Newbie
Location
UK
Car(s)
2016 3Dr GTi DSG CSG
What everyone else said, just drive it, the lights will go out, usually within a few feet. The spark putting your lead back on isn't an issue -they do that.

Also you will have to set your clock.



My clock set it self, must have done it through the GPS!
 

caleb.mk7

Go Kart Newbie
Location
Denver
Car(s)
2016 DSG
If you don't want to drive it, you can also turn the wheels all the way to the left and then all the way to right while stationary to clear the codes.
 

AsymmetricKururin

New member
Location
Canada
Car(s)
2017 Golf R
Turning the wheel seems to work

Thanks to Caleb.Mk7 for the advice about turning the steering wheel fully both ways to eliminate the faults. It seemed to work.

In my case, I still have one databus error on control module 13 (Automatic Distance Regulation) which I believe has something to do with the ACC cruise control safety feature. On my next drive I will try turning on the cruise control and adjusting the distance setting to see if cycling it on/off will eliminate the fault. Then I'll clear the DTC on that module and see if it comes back.
 
Top