ABS Sharan Bj. 2006 Fehler nicht behebbar | Posts 16+

TDI-GTI-4-Motion wrote:

The fact that the problem disappeared without the alternator suggests that it's related to the voltage.

And does the alternator that was temporarily installed (without a clutch) exhibit or create the same issue?

Quote:

It's unlikely to be a mechanical problem if it works with lower voltage. It definitely needs to be searched for in that direction.

Yes, but I suspect that the normal(!) ripple of the LiMa charging voltage is no longer being sufficiently smoothed out by the battery. Then the problem lies in the vehicle's electrical system rather than the alternator, which is confirmed by the result of replacing the alternator.
I don't know if a battery can develop such an internal problem while still providing enough starting current. If this is the cause, a new battery will solve the problem.

If that's not the case, the entire electrical path between the LiMa (alternator) and the battery positive and negative terminals must be meticulously checked for contact resistance, brittle cables must be replaced, and any potential problem areas (including screw and crimp connections) must be addressed.

It is also possible that there is a problem with the shielding (if present) of the sensor cable, causing excessive interference from the alternator ripple, which then disturbs the sensor signal to the point where it can no longer be properly evaluated.

mhernach wrote:

When I start the engine, there is no signal coming from the left front

. Without the engine running, the signal works perfectly. How did you check that? Can it be done using only VCDS, or also with an oscilloscope?

ulf wrote:

TDI-GTI-4-Motion wrote: The fact that the problem disappeared without the alternator suggests that it's related to the voltage. And does the alternator that was temporarily installed (without a clutch) exhibit or cause the same issue?

No, I didn't write that, nor did I mean it. That's precisely where the error lies.
I believe that checking the toothed wheel, etc., is unnecessary given this result.

TDI-GTI-4-Motion wrote:

I think checking the toothed wheel, etc., is unnecessary given this result.

Me too.

Quote:

Cross-swapping the control lines is not possible; the line at the control unit is simply too short icon_sad.gif. I would need to run new lines. I have already disconnected and reconnected the mass connections

(all the ones I know about) and then lubricated them with "rope grease" for preservation.

Also, does that also apply to the battery?

Okay, I will create a complete error scan and post it here.

Wow... that was a lot of information... I hope I don't forget anything...

1. I have already replaced the battery (with a used one from a Galaxy, 95Ah).
2. Swap the cables for the front sensors at the control unit... I meant that I can't do that at the control unit because the existing cables are simply too short; there's no room to maneuver. I would have to cut the wiring harness.

3. Vehicle scan? I suspect all control units using VCDS?

4. Oscilloscope... yes, I have one, but I don't know how to use it. I've tried, but I can't figure it out.

5. I read the speed from the speedometer!

I heard from a colleague that there's supposedly a voltage rectifier somewhere near the battery (information for a T5 bus), but I'm not sure if my Sharan has one.

mhernach wrote:

I've been having a problem with my ABS for about 1 year.

mhernach wrote:

So, I replaced the wheel bearings in the spring/summer... I can rule that out...

So, was we know is that the ABS error was definitely present before the wheel bearing was replaced. Could the "approximately 1 year" estimate for the ABS problem possibly coincide with the wheel bearing replacement date?

I suspect (despite the engine running issues) that there's a mechanical problem. Everything electrical has already been replaced. Therefore, I think it's more likely that the VL signal can be detected without the engine running, but not with alternator harmonics.

I think it should be possible to do, provided you open the cable harness wrapping by just a few centimeters. You can always re-wrap it with the original tape afterward, so no one will notice.

Greetings.
Guste.

Hello Guste100...

Yes, the problem existed before.
I replaced the wheel bearing because it was catching on something.
I also took a close look at the ABS ring. I think it's okay.

I'll take another look at the sensor issue this weekend. Unfortunately, I don't have VCDS, only a free version of VAG software.
Therefore, the vehicle scan will have to wait.

I was thinking of extending the cable from the sensor connector in the wheel well, running it over the hood, and bringing it to the other side (just for testing).

But what happens then if I know that the error will either move along with it or remain?

Best regards,
Michi

...and another one. This wouldn't be a problem for a regular user, but it ends here if you're using self-generated serial numbers. Please provide the text you would like me to translate from German to English.