ABS Sensor Values: Understanding and Troubleshooting

Hello! I've recently been having a problem with my Skoda Octavia 1.9 TDI where the ABS light is illuminated. The ABS system is also no longer working. After running a diagnostic scan, the issue was identified as being with the...
The front wheel has been identified as a potential source of error. However, nothing can be detected - the cable is fine, the contacts are not oxidized, and the sensor ring is clean.
Now, as a comparison to the left side, I wanted to measure the output voltage of the ABS sensor.
I'm not getting any usable results.
Shouldn't there be a measurable voltage when manually rotating the shaft at the contacts? Are there other ways to measure this?

Thank you in advance.. lg Kylie }

If possible, swap the left sensor with the right sensor and see if the error moves. If it does, you'll need a new sensor. That's the only likely cause if the wiring to the control unit is okay, and the sensor ring is clean and hasn't been damaged during any work on the wheel suspension.

"Replacing the sensors is almost certainly impossible (99.9% of the time) because they are usually stuck and can only be removed by destroying the component. Measuring the voltage is theoretically possible: rotate the wheel as quickly as possible and measure the voltage (use the smallest possible measurement range, and measure AC voltage!)."
When manually turning the wheels, you should aim for a voltage of approximately 0.2 - 0.4 V. You can also run the vehicle in first gear and then take measurements (of course, on a lift and carefully, due to the rotating wheels! - disable the ASR).

Hi Kylie.
'Gleißend' bedeutet, dass etwas so hell ist, dass es blendet oder unangenehm für die Augen ist. Es kann sich auf Licht, Farben oder andere visuelle Reize beziehen.
If a warning light is normally on, does it glow?
Or does it only flicker slightly for you?
Best regards, Kurt.

If you can't accurately measure anything (with an oscilloscope), you should only compare the readings on the right and left sides. This will show you if the faulty side is producing less voltage or no voltage at all when the wheels are turned.
It's probably the sensor, so it needs to be replaced.
As soon as the old one is out, it's finished.

Okay. As Klaus already mentioned, you can discard the sensor after you remove it.
They're so heavily rusted that you can't get them out without damaging them.

But I would probably just leave it as it is, because these sensors are cheap to reproduce, and if one breaks, it's not a big deal.
I've experienced that before too. Over time, water gets to the magnet and it starts to oxidize.
In rare cases, the magnet may have shavings on its surface, which can cause it to display incorrect readings.

@alsch: Thanks for the tip. The readings were correct. The old sensor was defective.
I installed a new one, and the readings are back to normal. The ABS warning light is now off. THANK YOU.
@Kuestenkuddel: Sorry for my big mistake! But I also can't precisely define whether it's glowing, flickering, or something else... then define it as 'ON' if you're that bored.
@Tagessuppe: Yes, thank you, I've already exchanged it. I just wanted to get the readings to see if the sensor or the cable is faulty.

Great forum! Thanks, Kylie.