Question

EPC braking light switch

Hello all, this is my first time posting here. However, I own a VW however I’ve had the brake lights turning on unless I press the braking pedal about half the way down so I removed the brake light switch the proper way after researching how and I adjusted manually that long plunger the way actually the lights turn on when I instantly press the braking pedal. That way actually safer instead of pushing half the way down so they lit up (during the heavy traffic they were usually won’t lit up since I’d press slightly the pedal) but now it’s working fine with my little adjustment. However I’ve got the EPC came on my dash. I tried erasing the fault codes of braking switch but it goes back after driving the car. Any help how to turn off the EPC light without readjusting the braking light switch ? Because I’m really satisfied with the new adjustment for security reasons. Thanks in advance.

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Comments
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Answer
Fault code

Hi, blvvdy; What year and model VW? What fault code did you retrieve? I can look it up with that info.
Loren

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EPC brake light switch

It’s a 2008 polo 9n3 and the OBD scan shows the error in the brake light switch. However I tried manually readjusting the switch again and the EPC goes off but after the car is driven for a minute I suppose then it comes back.

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It probably will go off itself, eventually

You could crank the car (just in case it's needed) and then press the brake pedal 50-100 times, till it hits the number that turns the dash warning light back off.

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It’s been 3 weeks now

So I’m not sure if it’s going to turn off on it’s own.

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call a VW dealer

Ask to speak to someone in their repair area. They can tell you the procedure you can do, or if you'd need to bring it in. I do know if negative battery cable is disconnected, typically all codes get reset, but that can cause some other problems at times, such as radios which then need to be reset after a power loss.

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VW dealer

I’ve already contacted them but they told me to buy a new switch which I’m afraid that will bring back the old light timing adjustment. That’s why I want to stick up with my adjustment and force the car computer to accept it. Because it is thinking that the switch is faulty but it’s not.

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Isn't it a proper switch replacement?

Did the old switch have some sort of digital sensor on it and the new switch doesn't?

It seems the EPC warning light covers more than just braking system. How are you so sure that's what caused the light to come on?

If the VW has an ABS system with the brakes, then a wheel sensor could be causing the light to remain on. Thankfully on my Dodge Grand Caravan the brake light and the ABS are separate warning lights.

https://www.volkswagensantamonica.com/blog/what-is-the-vw-epc-warning-light/

Also check the fuse shown in this video.

Post was last edited on August 26, 2019 11:50 PM PDT

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It’s been 3 weeks now

So I’m not sure if it’s going to turn off on it’s own.

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Answer
Fault code

As James noted,
"It seems the EPC warning light covers more than just braking system. How are you so sure that's what caused the light to come on?" What is the number of the fault code? It will start with "P". Example: P0401

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Fault code

Because whenever I take off the switch and readjust it, the EPC light goes off but then after driving it for a few minutes it comes back. Besides I’ve ran an obd scab and it showed me this “16955 - Brake Switch (F): Implausible Signal
P0571 - 35-00 - -”

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are the brake lights coming on?

Have you checked? Also,did you check the wiring mentioned in the video where it comes into the trunk area by the driver's side hinge? Do you have cruise control? Is the brake shutting it off when you use the brake?

https://www.autocodes.com/p0571_volkswagen.html

Post was last edited on August 27, 2019 10:58 PM PDT

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Yes the brake lights coming on

The switch obviously functioning well. And I don’t think there’s a short in circuit otherwise it wouldn’t work would it.

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and cruise control?

Have it? Does hitting the brake, cut it out as it should? The ECM obviously isn't getting the message, since it's what generates the warning light to come on. So, the lights could work, but still be a short to the ECM in the wiring. Have you checked the fuse indicated in the video yet?

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cruise control

The car is somehow “old school” so it has no cruise control. Just change the gears and accelerate at no limits. Haha however I’ve checked all the fuses and they are all seemed alright. Couldn’t tell which one is for the switch so I checked them all. I might check the cables as you mentioned. But I’ll try as well pulling out the plunger to the maximum and then put it onto the pedal so it would adjust by itself since that’s how they are installed the right way. But I’d loose my “perfect adjustment” for the lights timing.

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Answer
EPC

Hi, blvvdy; That code (p0571) is coming back to brake pedal position sensor. I don't have the info. for a Polo 9n3. What would the US version be called?

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EPC

I’d reckon it’s called Polo GTI 2008 or polo facelift

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