A4 Electronic HandBrake Issue

[AndyK]

Hi All

Does anyone know of a problem with the electronic handbrake system? I have Audi A4 Avant 2 litre Diesel 2010 plate - when operating the electronic handbrake it doesn't always engage - I lift the switch, it starts to, the red light comes on, you can feel the change on the footbrake - and then it turns itself off and the light goes out. It doesn't happen every time and it only seems to happen once until the ignition is cycled off/on so you cannot reliably make it happen. I've had the vehicle for about 2.5 years and its only the last year that its been happening. So many times I opened the door and the car is merrily rolling along and I've gently bumped a couple of cars too because of this. I now try to check and put the car in gear when the key is out but don't always remember - its really got to the point where I think it may be a safety issue. Any clues/knowledge of this would be most welcome. Does AUDI monitor this site? I know there some technical employees that monitor and post - maybe you guys have heard about this........Thank you.....

[James]

The electronic parking brake should self adjust so it will always hold as the brake pads wear. Sounds almost as if it could be an electronic issue rather than a physical/mechanical one?

[AndyK]

Hi

 

Thanks for reply....

Yes I agree - I think it is electronic - or software if there is any software control on that part of the braking system.

The brake works fine when it does engage - almost too well as there is no proportional control unlike a conventional handbrake - either off or on!

[James]

The only other thing I would take a guess at is either a temperamental motor or even the switch itself?

Do you get any error codes or warnings when it doesn't work? 

[AndyK]

Hi James

 

No error codes or warnings....only the occasional 'bump' when I've rolled into something....!

I don't think it is the switch as the light comes on and brake starts to energise every single time...

Possibly the motor but its strange that it will only happen once until the ignition is cycled off/on.

I am an electronic engineer and although I am not familiar with Audi specifics I've come across so many software bugs that software is definitely a 'person of interest'

 

Regards...

[James]

Strange as most of the people who report failures online seem to indicate an error but it's weird as yours is intermittent.

The only other thing I reckon that may be worth a try is taking the motors off and cleaning it all up properly to see if that helps?

[David JA]

Yes,

 

2017 A4 Avant.  First time it gently rolled into another car, which prevented it from going through a car showroom window!  Happened again today.  Luckily no damage.

 

the fist time I put down to human error, but the developed a bit of OCD about constantly checking the handbrake, so it was definitely on.

alam has been going off for no reason for the last couple of weeks, so not sure if connected.

[AndyK]

Hi all

I posted several years back about this parking brake  problem I was having and never got to the bottom of it...although it still happens from time to time.

But I was talking to a mechanic recently and he mentioned that it might be an intermittent pressure (or vacuum) switch in the braking system but didn't elaborate...

Anyone know which switch this might be to cause this problem - and whether it is DIY or AUDI service?

Regards

[Steve Q]

Great to see you back Andy. Yes it could be that, the only way you'll know is changing the parts. I'd say it's an Audi job as any parts of the electronic handbrake system will need to be coded to the car. 

[ninjag]

It's pretty quick and easy to disconnect the EPB gear and check it out visually including manually operating it just as a process of elimination.