General Question (Electronic Parking Brakes)

[khaledabdulaziz]

if a car has electronic parking brakes
and it got stuck even on moving, is there a way to disable it permenantly till i find a new motor for it?

 

[PetrolDave]

What car are you talking about, not all cars with EPB are the same? Please post a VCDS Auto-Scan...

 

[khaledabdulaziz]

i dont have a car on me with this problem, im asking general question, is there a possibility to disable EBP in some cars

 

[PetrolDave]

i dont have a car on me with this problem, im asking general question, is there a possibility to disable EBP in some cars

I don't *think* there's a "one size fits all" answer to that, but let's wait for the real experts to reply

 

[DV52]

@khaledabdulaziz : Hi

I'm certainly no expert and I agree with @PetrolDave about a unified answer for all cars that are fitted with EPB. However, purely from a safety perspective - I would very much doubt that the designers at VAG would allow a car to be operational with EPB disabled.

The other problem with EPB is that is a highly integrated facility that connects to multiple in-car systems. So disabling EPB would impact lots of other components.

Perhaps you might get an appreciation of the complexity of the EPB system by reading the SSP here

Don

PS: Admin - is the TLA "EPB" sufficiently used to qualify for the forum lexicon?

 

[Uwe]

Since this is such a general question, moving to General VW/Audi Repair.

If I had a car with a stuck EPB motor, I would try to open the motor using a current-limited (to about 10A) 12V power supply. Applied directly to the motor leads in one direction, it should cause the motor to try to close. In the other direction, it should try to cause the motor to open. If that didn't open it, then I there would be no choice but to mechanically disassemble things.

As for disabling the EPB system entirely: I'd get a wiring diagram and pull the fuse(s) that supply power to it. This will certainly result in fault codes in other modules as well as some warning lights, but I'd expect the car to remain driveable enough to get it where it needs to go to get repaired.

-Uwe-

 

[Uwe]

PS: Admin - is the TLA "EPB" sufficiently used to qualify for the forum lexicon?

Indeed. Done.

-Uwe-

 

[DV52]

Since this is such a general question, moving to General VW/Audi Repair.

If I had a car with a stuck EPB motor, I would try to open the motor using a current-limited (to about 10A) 12V power supply. Applied directly to the motor leads in one direction, it should cause the motor to try to close. In the other direction, it should try to cause the motor to open. If that didn't open it, then I there would be no choice but to mechanically disassemble things.

As for disabling the EPB system entirely: I'd get a wiring diagram and pull the fuse(s) that supply power to it. This will certainly result in fault codes in other modules as well as some warning lights, but I'd expect the car to remain driveable enough to get it where it needs to go to get repaired.

-Uwe-

Uwe- are you sure? I don't know about the wiring arrangements for other model cars, but at least for MQB platform vehicles -I'm fairly certain the management of electrical current for the 2 x EPB motors is solely the responsibility of the hex03 module (i.e. EPB is integrated into the ABS module). Again AFAIK, this includes current limiting for both operational and overload/fault situations - so neither of these motors are fused in the conventional manner. Both supply wires to each of V282 (left) and V283 (right) parking brake motors are terminated on the connection block on j104.

In situations where the EPB motors are jammed-close it's certainly possible to use your suggestion if this happens at a workshop - but the DC current device is a fairly specialized piece of kit. I had understood @khaledabdulaziz question to relate to what's possible if the EPB fault happens on-the-road. I don't imagine that many folk carry around (in their cars) a standby 12V-operated, DC current-limiting device with sufficient capacity to drive the EPB motors.

Don

 

[Uwe]

Uwe- are you sure? I don't know about the wiring arrangements for other model cars, but at least for MQB platform vehicles -I'm fairly certain the management of electrical current for the 2 x EPB motors is solely the responsibility of the hex03 module (i.e. EPB is integrated into the ABS module). Again AFAIK, this includes current limiting for both operational and overload/fault situations - so neither of these motors are fused in the conventional manner. Both supply wires to each of V282 (left) and V283 (right) parking brake motors are terminated on the connection block on j104.

Good point -- if it's one of the newer cars with EPB integrated into the ABS, that might make life more difficult. My mind set was with the older cars that have a separate EPB module.

In situations where the EPB motors are jammed-close it's certainly possible to use your suggestion if this happens at a workshop - but the DC current device is a fairly specialized piece of kit. I had understood @khaledabdulaziz question to relate to what's possible if the EPB fault happens on-the-road. I don't imagine that many folk carry around (in their cars) a standby 12V-operated, DC current-limiting device with sufficient capacity to drive the EPB motors.

If push came to shove, I'd use a car battery (pretty much every car does carry one around all the time) and a 60 watt headlight bulb in series. That won't quite get you 10 amps, but I think it would be worth trying in a pinch. It takes relatively little current to spin the motor until it reaches its stops. Note: I've heard of some people who've used a car battery w/o any current limiting device, and strongly advise against this. It will be OK until the motor reaches its stops, but then the current goes way up and you risk burning out the motor.

-Uwe-

 

[DV52]

If push came to shove, I'd use a car battery (pretty much every car does carry one around all the time) and a 60 watt headlight bulb in series. That won't quite get you 10 amps, but I think it would be worth trying in a pinch. It takes relatively little current to spin the motor until it reaches its stops. Note: I've heard of some people who've used a car battery w/o any current limiting device, and strongly advise against this. It will be OK until the motor reaches its stops, but then the current goes way up and you risk burning out the motor.

-Uwe-

Uwe: hmm.......... I will of course bow to your expertise in such matters and if we were talking about a normally functioning DC motor - I reckon that you just might get away with using a series lamp as ballast for the car battery on the side of the road (albeit I'm not quite sure how you calculated a 60W resistor for a 10amp supply from a fully charged battery with nominally 13.8 volts).

However, we are considering a situation where the EPB motor has failed to turn for some reason. As I have said - If this has happened because the controlling module supply has failed (and the downstream EPB motor components are OK), then your solution probably would work. But likely if the control module is the problem - the car has bigger issues !

But, if the problem is a "locked" DC motor because the downstream gear mechanism, or the brake rotor has jammed - the time frame for normal inrush current will likely be extended substantially until the rotor starts to turn (if indeed it turns at all). This means that it likely will be a considerable time before the motor will generate sufficient (or any) back EMF to counter what effectively will be an electrical short-circuit of the battery through the DC motor winding (yes, with the series limiting resistor in-circuit)

Fact is though that to get the EPB motor to move at all in this second scenario will almost certainly necessitate a higher electrical current than normal meaning that particular attention will need to be given to I^2R heating losses in the motor coils. Not sure that even if the car owner carried a bunch of different wattage lamps for this purpose (i.e. to select different current values) - the risk of coil damage could be managed as a road-side exercise with your solution !!

Don

PS: As for using a car battery w/o any current limiting mechanism - a truly foolish option indeed!!

 

[khaledabdulaziz]

@khaledabdulaziz : Hi

I'm certainly no expert and I agree with @PetrolDave about a unified answer for all cars that are fitted with EPB. However, purely from a safety perspective - I would very much doubt that the designers at VAG would allow a car to be operational with EPB disabled.

The other problem with EPB is that is a highly integrated facility that connects to multiple in-car systems. So disabling EPB would impact lots of other components.

Perhaps you might get an appreciation of the complexity of the EPB system by reading the SSP here

Don

PS: Admin - is the TLA "EPB" sufficiently used to qualify for the forum lexicon?

after reading your link, if i had a car with EPB and ABS are separated, can i uninstall the EPB from 19-can gateway and remove the " The electromechanical parking brake control unit J540 " plug, and it will act like EPB is not functioning anymore, maybe my question is kind of dumb and beginner question, but would love to know if its possible, and if its possible, how would i do it in case the parking brake motors are stuck. and how to do it if EPB and ABS are not separated.

thanks.

 

[Uwe]

I reckon that you just might get away with using a series lamp as ballast for the car battery on the side of the road (albeit I'm not quite sure how you calculated a 60W resistor for a 10amp supply from a fully charged battery with nominally 13.8 volts).

I didn't. If I was using a lab supply, I would set the current limit to 10 amps. But if I didn't have one of those, I would use whatever is available to limit current and a 60W headlight bulb is ubiquitously available at any auto-parts store. Heck if it's a low-line car with halogen headlights, two of them will be available in the car.

But, if the problem is a "locked" DC motor because the downstream gear mechanism, or the brake rotor has jammed - the time frame for normal inrush current will likely be extended substantially until the rotor starts to turn (if indeed it turns at all).

Sure. If it can't be made to turn at all with 5-10 amps, then mechanical disassembly is likely called for.

-Uwe-

 

[Uwe]

would love to know if its possible, and if its possible, how would i do it in case the parking brake motors are stuck.

Stuck how? Mechanically stuck due to corrosion? "Stuck" due to control module failure and thus lack of power to turn them? "Stuck" due to a failure in the motor itself?

And how to do it if EPB and ABS are not separated.

Call a tow-truck?

Provided they are not abused by people incompetent people who don't know how to work on them, EPB systems are actually pretty reliable. My daughter drives a 2005 4F A6. The car is now 15 years old; never a problem with the EPB system.

-Uwe-

 

[DV52]

after reading your link, if i had a car with EPB and ABS are separated, can i uninstall the EPB from 19-can gateway and remove the " The electromechanical parking brake control unit J540 " plug, and it will act like EPB is not functioning anymore, maybe my question is kind of dumb and beginner question, but would love to know if its possible, and if its possible, how would i do it in case the parking brake motors are stuck. and how to do it if EPB and ABS are not separated.

thanks.

@khaledabdulaziz: Hi - you have Uwe's suggestion and the associated dialogue as points for consideration. Both Uwe and I are trained in electrical theory hence our predilection for a particular approach. However, to balance the debate - perhaps a "spanner-jockey's" perspective might be educational - see video below.