EFB parking brake warning light flashing on the instrument cluster

I have a Passat 3C, 140 horsepower, DSG transmission, manufactured in December 2008, and I'm experiencing a problem with the electronic parking brake – or possibly something else.

Generally, everything seems to be functioning normally. The brakes work, the auto-hold feature works, etc. However, it has been observed that the handbrake symbol in the instrument cluster flashes quite frequently. But there is no regular blinking interval and no beeping sound. Just a very brief, frequent flashing, even with the engine running while the car is stationary. The EFB switch does not light up simultaneously; it is off when the brake is released and on when the brake is engaged.

I read the car's diagnostic data using VCDS. There was an intermittent issue with the radio, and the system is unable to access the control unit for the trailer hitch. "However, this has never happened before, and it was already installed and activated at 10-20,000 km (before 90-100,000 km), and even then, I was never able to detect any errors."

Where could the flash be coming from?

VG

Hello,

If the EPB functions in the same way as in the Audi A6 4F, the closed/open state of the brake will be detected by monitoring the current flowing through the actuator motors.
The indicator light in the instrument cluster illuminates either due to a direct cable connection or a CAN message from the Electronic Parking Brake (EPB) to the instrument cluster.

So, it's either a software error in the involved control units or a loose cable.

Was if there's any confusion about the brake pad wear indicator?

Best regards, Rainer.

Hey Rainer!

Thank you for the feedback. What do you mean by "the symbol in the instrument cluster illuminates either due to a dedicated cable or a CAN message from the EPB to the instrument cluster"? So, with a "cable of my own"?

Unfortunately, I mistook it for the brake pad warning light (yellow). It's definitely the LED light on the parking brake that stays red when it's activated, or turns off when it's released – that's how it works for me too.

However, it flashes intermittently on my dashboard at completely irregular intervals – not a typical blinking pattern. I haven't yet tried to see if it still happens when the car is off but the ignition is on. It happens while I'm driving, and also when I'm stopped with the engine running.

Is there any setting in VCDS that allows me to monitor the LEDs in the instrument cluster? Sure, please provide the German text you would like me to translate into English. I will also try to identify potential triggers if they are mentioned or implied in the text.

Measurement block data: The brake opening/closing actions on the left and right sides are identical, and the current (presumably for closing?) was a maximum of around 17 amperes, but again, the left and right sides are identical.

VG

Hi,

I'm not sure if the AI measurement data includes corresponding status bits. However, the brake control unit definitely provides a corresponding status. I would monitor/log that and see if anything unusual happens. If there's nothing out of the ordinary, then it's probably not related to that control unit.

A wiring diagram would also be helpful to determine how the signal reaches the AI (artificial intelligence) system.

Best regards, Rainer.

Hello Reddi,

You are not alone with this problem. This error is not uncommon with the 3C. However, the indicator light on the AI system usually stays on continuously.

There is a corresponding TPI (Technical Product Information) document with the number 2021874/5.
There, the affected funds are listed.

In most cases, however, there is an error hidden within.

Is there, or was there, an error code registered for your vehicle?

If your financial situation is affected, this link might be helpful...

http://wiki.ross-tech.com/wiki/index.php/02443

Best regards,

Michael.

Hey Ich_Can_nix!

Thank you for the tip about the TPI. Does Volkswagen always offer this as a gesture of goodwill? I usually do everything myself or take it to independent workshops.

Anyway, I briefly recorded the error (the flashing): [url][/url]

VGhttps://youtu.be/KVms3SnbJAU{MARKER}

Hello Reddi,


The illumination/flashing could be triggered by the control unit querying the status of the switch.

As Rainer already mentioned, potential sources of error include...

- Switch

- Control unit

- Cable break.

- Ki (unlikely)

to be considered.

Personally, I would check the switch for continuity and wear.

Does the error also occur when the "auto-hold" function is disabled?

Do you have a bug report?

The radio is an "external radio" and was already installed before the error occurred?


Whether VW is willing to cover the repair costs as a goodwill gesture in your case, you need to discuss with the authorized workshop of your choice.


Best regards,

Michael.

Hey Ich_Can_nix!

Thank you again for the tips. I replaced the switch with a newer one today, but the problem still persists. As a result, I disconnected the battery for 15 minutes - the problem persists.

This is an original VW radio (RCD310) from the factory. It was simply connected to a Bury hands-free system.

I almost always have Autohold turned off, but I've now turned it on for testing purposes. This works perfectly, however, the problem still persists.

I've attached the error log for your review. The first one happens after disconnecting the battery, and the second one happens after clearing the error codes and driving 50 meters.

I also can't find anything in the measurement blocks, paths, etc., that indicates a brief status change when the light flashes on the dashboard. Either the flash duration is far too short, or it's impossible to determine it.

Darn it. :-/

VG

To me, it looks like a short circuit. If there are no visible signs of chafing or a broken cable, it becomes difficult to determine the cause.

Reddi wrote:

I replaced the switch with a newer one today - the problem still persists.

Did you install a used part? "The Autoscan clearly states:"

Sure, here is the translation of the text from German to English:

"1 error found:"
03200 - Button for electric parking brake (E538)).

I would start by replacing the button and then see what happens next.

vag-driver wrote:

1 error found: 03200 - Button for electric parking brake (E538)). I would first install a new button and then see what happens.

Yes, the error is occurring because I disconnected the original button (part number 3C0927225B) and installed a new one (the updated version, part number 3C0927225C REH). Immediately before I disconnected the button, I didn't have this error, and it hasn't reappeared after I cleared it.

VG

Hello Reddi,

You didn't necessarily have to replace the switch to test it.

The error for the button is repeatedly and sporadically being saved. Circuit error!

Have you checked the wiring to see if it's in good condition?
No contact resistance?


Starting with WVW ZZZ 3C Z 9E 090950, the optimized EPB control units will be installed.

Please double-check (have it checked) carefully and don't exchange it immediately.


Best regards,

Michael.

Ich_Can_nix wrote:

...you didn't necessarily have to replace the switch to test it. The error for the button is repeatedly and sporadically being saved. Circuit error! Have you checked the wiring to see if it's in good condition? No contact resistance? Starting with WVW ZZZ 3C Z 9E 090950, the optimized EPB control units will be installed.

If you're referring to error frequency 3, then it's unlikely to be a cable defect from the button. I've taken it out at least twice. And if the error frequency increases by 1 with each flash (or trip), it should be much higher. Could there still be a cable defect from the button, considering this? If that's the case, I'll need to get the wiring diagram and test all the pins.

I'm actually from the older generation when it comes to control units. Something in the 60,000s is my PIN.

Could it be the motors themselves? Do they have a sensor? I can easily activate and deactivate them using the actuator diagnostics (?). The number of actuations is the same for both. The maximum current draw is approximately 17A for each. The tension is consistent throughout the pages.

I replaced the switch myself because it's supposed to be a common cause, I didn't want to test everything, and I had a lot of hope.

Best regards,

Hello! It's been a long time. I found the solution in the meantime.

If I disconnect/unplug the wire between the EPB control unit (T30/2) and the fuse box terminal (T36/6), the LED in the instrument cluster always remains off.

After replacing the control unit with a "new" one (3AA907801J) and painstakingly calibrating it, everything is working perfectly again.

"Best regards and many thanks to all those who provided assistance!"