Help needed with ABS/ESP and AGR valve!!!

Hello,

Problem 1:

I have been receiving the error message '16955 Brake light switch - F, implausible signal' for about a week.

Also neuen Schalter für 14,- gekauft, heute eingebaut, und: NIX, immernoch dasgleiche, beide Warnlampen (ABS und ESP) leuchten weiterhin ... What now?

Problem 2: As of today, the preheating light is flashing: Error code: 17849.
Exhaust gas recirculation (EGR) valve - short circuit to ground / open circuit.

No noticeable loss of performance, otherwise no abnormalities, except that the light is blinking and according to the Volkswagen manual, I should take it to a workshop.

Has anyone had any experience with this?

I would be very grateful to you.
Thank you and greetings.
Mazzam.

Hello.

Regarding both errors, I can only suggest checking the plugs and cables as thoroughly as possible. If you find nothing visually wrong, then proceed to test them with a multimeter.

Greetings!

mazzam wrote:

I have been receiving the error message: 16955 Brake light switch - F, implausible signal

for about a week.


Does your model also have two separate switches on the brake pedal, or is there one with four connectors?
If they are still separate units, then both must be configured identically (check with VAG-COM to see if they shift simultaneously).
Also, please also check if your brake lights are still working.

mazzam wrote:

Error code: 17849 Exhaust gas recirculation valve N18 - Open circuit/Short to ground

Check the valve resistance, inspect the cables.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

Hi and thanks in advance!

Regarding problem 1:

In my model, I have 4 poles on the brake light switch, and the brake lights are no longer working (all 3). Additionally, I've noticed that the license plate lights are getting very hot .
I do have a VAG-Com device, but I haven't explored its full capabilities yet; I've only used it to read and clear error codes so far (can anyone help me?).
What/how should I measure there? What results are within the normal range?

Regarding problem 2:

I removed the solenoid valve (N18), cleaned it externally, checked the contacts, and reinstalled it. For a trip of 30 km, nothing was illuminated, but then it returned to the same state: the preheating light blinked, and the errors appeared as described above... It usually occurs when idling and then doesn't turn off anymore...
Valve resistance is approximately 430 ohms; could that be correct?

Thank you in advance, and best regards, MAZZAM.

Regarding problem number 1: This is usually a purely mechanical issue. Carefully examine the cables directly at the connector – look for any kinks or bends. Use a multimeter to check the connection to the control unit, and while doing so, firmly wiggle the connector (brake switch).

It's probably the brake light switch. You really have to be careful when installing it on a Passat. I spoke to a friend of mine (a workshop foreman at a small VW service shop in the Netherlands) who once ruined a new one during installation. You can't see the problem, but I've seen the defective switches myself. Somehow, you have to retract it and then it should extend again when installed (if I remember correctly).

Perhaps you can find instructions here on how to properly install this part.

...regarding the "too hot" indicator lights: Unfortunately, this is normal!

Try touching a 5W wedge base bulb (W5W) or a 4W metal base lamp (T4W) that has been turned on for just a few minutes... You'll horribly burn your paws!

OT: In terms of longer lifespan and reduced sensitivity to shocks (e.g., from the tailgate slamming on vehicles with license plates attached), I can confidently recommend the version with 3W LEDs. They are available from all major manufacturers at the same price as the 5W versions. The brightness is hardly noticeably lower, but the lamps no longer turn black inside and seem to have an almost endless lifespan. I use them for parking lights and license plate illumination.

Hello again,
So, here's the thing:

Regarding problem 1: I received the brake light switch from a friend, and it came loose with an extended spring. I installed it myself. While doing so, I checked the cable as much as possible for any breaks or defects. However, since then, things haven't gotten better; in fact, they've become worse... My brake lights are no longer working, and this morning (5:45 AM), someone almost hit me...
Has anyone else had a similar experience???
I would be very grateful to you.

Regarding question 2: I've now read that many people here in the forum are blocking their AGR valve, and I will do the same. However, this doesn't change my warning light or the error message. Question: Is it possible to bypass the electronic signal or 'quiet' it with a resistor?
Thank you all in advance!
Greetings, MAZZAM.

mazzam wrote:

For problem 1: I received the brake light switch from a helpful person, and it was loose with the spring fully extended. I installed it.

Then it's the other way around. It can only be extended once it's installed. In any case, if you mess with it even once (you can manually extend and retract it), it breaks. I only saw the broken part, but I couldn't identify a specific defect. Maybe someone at the parts supplier fiddled with it?

Hi,

It seems your AGR valve is failing. The resistance should be approximately ten times lower (I believe it was around 22 ohms). Otherwise, try searching online or buying a new valve.

Adding a metal lid is also not the worst option.

Regarding your brake lights:
- Have you checked the fuses and bulbs?
- Voltage measured and cables checked for continuity?
- Have you ever tested the switch with the cable connected while it's in an unmonitored state?
Don't focus on the engine control unit (ECU) yet. As long as the bulbs are not working, the ECU won't receive any meaningful information and will store an error (the bulbs act as pull-down resistors). So, first get the bulbs working, and then investigate further.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

Hello again,
Okay, after several attempts to fix the brake light switch defect, I'm giving up now.
The brand new brake light switch from VW is working, and my brake lights (all three) should also work. At least, the wires are all okay, and they work perfectly with a different power source. I've also measured the voltage at the connector of the brake light switch and found about 7-8V, so the wiring seems to be intact, and there are no visible defects. However, what I noticed is that the warning lights for ESP and ABS only illuminate when I release the brake pedal, not while braking. If anyone has any ideas about this, please let me know. For now, I'm driving without brake lights and with a sticker covering the light on the dashboard.

Regarding the AGR valve issue: it's only happening sporadically now, and I haven't experienced any loss of power or other negative effects. Therefore, I've just put a sticker over the dashboard warning light and am continuing as normal...
Everything sounds very amateurish, but I just don't know what else to do...
greetings mazzam

Hi there,

So, after several attempts to fix the brake light switch defect, I'm now giving up.
The brand new brake light switch from VW is working, and my brake lights (all 3) would also work. At least, the wires are all okay, and they work perfectly with a different power source. I also measured at the connector of the brake light switch and found about 7-8 V,
Do you happen to have LED taillights installed?

Hello again,
Okay, I don't have LEDs installed; I'm using standard bulbs (originally from a 3BG, but with an adapter, which has been working flawlessly for the past 3 months).
Yesterday I bought and installed a new EGR valve (€90), but the result is still the same: I'm still getting an error message, and the engine still has poor performance.
I give up!
Greetings, mazzam.

mazzam wrote:

Hello again, Okay, so I don't have LEDs installed, but rather standard bulbs (from a 3BG, although with an adapter, which has been working flawlessly for the past 3 months). Yesterday I bought and installed a new EGR valve (€90), but the result is still the same: I'm still getting an error message, and the engine is still running rough. I give up! Greetings mazzam

.

What type of EGR valve did you replace? Does your EGR valve use vacuum or does the cable connect directly to it? If the cable connects to a pressure sensor (valve), then you need to replace that sensor, not the EGR valve itself. I'm not sure which type of EGR valve you have.

"Because of the brake lights. It's obvious that if the brake lights aren't working, the switch is probably broken (it's very rare for a cable to be faulty, unless it's been damaged by rodents or something), even if it's new. Go to the workshop and get a new one, and test it immediately without installing it; then you'll know for sure."

Good luck, and don't give up!

Hi everyone,

It has been clarified: It was fuse number 13 in the control panel... All lights are off, and the vehicle will be sold.

Thank you everyone.

MAZ