ABS Light - PeachParts Mercedes-Benz Forum

Frank Reiner · #1 10-18-2016, 09:28 AM

Quote:

Originally Posted by lorainfurniture

Don't quote me, but I believe they are Hall effect sensors. Trace the wire in to the engine compartment, you will find a plug. There should be a reading of " x" ohms, and when you spin a he wheel that value should fluctuate.

Someone with a service manual can chime in with the specific readings.

If the abs turns on on the first press of the brake pedal I'd be looking for a broken wire, or something a bit more obvious.

The matter of quoting is inevitable; but the sensors are not Hall type, they are simply two-wire, magnetic, inductive pickups, aka VR sensors. There should be conductivity through the two wires.
Fronts: .85 - 2.3 Kohms
Rear: .6 - 1.6 Kohms

85 DSEL · #2 10-18-2016, 09:45 AM

Quote:

Originally Posted by Frank Reiner

The matter of quoting is inevitable; but the sensors are not Hall type, they are simply two-wire, magnetic, inductive pickups, aka VR sensors. There should be conductivity through the two wires.
Fronts: .85 - 2.3 Kohms
Rear: .6 - 1.6 Kohms

Thank you for this info, when I have the time to get into it, I'm sure it will prove useful.

Mxfrank · #3 10-18-2016, 11:04 AM

Another thing you should do is pull the sensors from the hubs and clean the tips. Because they are magnetic, they tend to pick up iron filings and metallic debris, which screws up the system.

lorainfurniture · #4 10-18-2016, 03:01 PM

Quote:

Originally Posted by Frank Reiner

The matter of quoting is inevitable; but the sensors are not Hall type, they are simply two-wire, magnetic, inductive pickups, aka VR sensors. There should be conductivity through the two wires.
Fronts: .85 - 2.3 Kohms
Rear: .6 - 1.6 Kohms

Correction is due on that one. I was going off the top of my head on a very foggy memory of my abs troubles many years ago.

Bottom line is that you should get some reading of resistance when tested. Likely one of them is very dirty, or an obvious broken wire. Should be pretty easy to track down.