MB Speed detector sensor.

[Normand]

I ask this question before and did not get a reply. How will you know which one is defective?

 

[rollerbearing]

Scan tool should be able to tell you - though I'll need to verify this. Also, it appears these are simple inductive coil pickups so even a basic ohm-meter reading may be good enough indication. Multiple other ways of diagnosing as well. But if it all comes down to a choice of ruined trip or not, or mobility or not, one could just do all four. Major time suck - but probably no worse than a day of driving and another day eating biscotti waiting to get it done at MB.

 

[mkc]

Adding a follow-up now that ours is repaired.

It apparently was a switch on the brake pedal, not a wheel sensor, that had failed. It did cause the coach to be in limp mode, at least reduced power mode, for the drive out.

We did have the driver's airbag recall and a cracked pixel matrix display replaced under warranty while there. Very pleased with the service at MB of Knoxville.

Michelle

 

[avanti]

I ask this question before and did not get a reply. How will you know which one is defective?

I have been able to diagnose the specific sensor using my clone Star Diagnostic system.

 

[rollerbearing]

2 of Holstein Parts 2ABS0847 ABS Speed Sensor
Holstein Parts 2ABS0848 ABS Speed Sensor
Holstein Parts 2ABS0851 ABS Speed Sensor

This is what I ordered. Do your own double checking on these numbers to be sure.

If someone has access to the MB parts catalog or a receipt for past repairs it might be good to check these numbers. My Holstein parts came and look to be of good quality - the MB equivalent part numbers were marked on the bags.

They were:

2ABS0851 = 9065401217
2ABS0847 = 9065400317
2ABS0848 = 9065401117

 

[imstilllarry]

What part number is for each specific wheel? When I get back home I’m going to take mine apart and clean them. But I would like to have spares and know which is which. Thx



Sent from my iPhone using Tapatalk Pro

 

[jmahar3]

Rollerbearing my right rear sensor went out on 2014 Navion on 2013 Sprinter Chassis. Received replacement part from Rockauto Bosch P/N 0 265 009 341. The replacement however does not fit all the way in and I didn't want to force it as the old one didn't have a snug fit. Old sensor widest point .408" New sensor widest point .429". It is the correct sensor and I just need to put more pressure to get it to seat?

Appreciate your efforts, John

 

[rollerbearing]

I got the holstein parts. When I entered your bosch number it looked to be the correct unit. Let me get my calipers and I'll go measure my holstein units.

I strongly suspect you could just "polish" it down in diameter with a long strip of abrasive cloth - like you might for a crank journal. The sensing coil and cable are probably deep enough in the body plastic. I wouldn't touch the end face however.

 

[avanti]

So, is all of the following correct:
1) Both front sensors are identical (i.e., the same part number).
2) The two rear sensors have different part numbers, but the only difference is the cable length?

If so, which rear part has the longer cable? I assume that it would serve as a "universal donor".

 

[rollerbearing]

Holstein's are about 0.385" diameter for about half their length. Then there are 3 longitudinal ribs about 0.025 wide and 0.025 tall above the cylinder. These ribs look like they may be for indexing or frictional fit. Really the sensor should be indexed by the mounting bolt so I suspect it is for fit. I would not hesitate filing the ribs off these Holstein sensors if I needed to in order to make them fit.

 

[rollerbearing]

Looked at it close - the darn things are black! There are three identical ribs and a forth rib oppossite one of those. The diameter effectively is about 0.430 inches in the ribbed area. Plus or minus a thou -as I had to use my vernier - couldn't find the dial caliper and the digital's battery is dead - to have young eyes again!

 

[rollerbearing]

So, is all of the following correct:
1) Both front sensors are identical (i.e., the same part number).
2) The two rear sensors have different part numbers, but the only difference is the cable length?

If so, which rear part has the longer cable? I assume that it would serve as a "universal donor".

1) - Yep.

2). - Yep different part numbers (MB, Bosch, and Holstein). I believe rock auto gave the lengths for the bosch units. When I hold my Holstein rears side by side they are identical except for the part numbers. So maybe they (holstein) went the universal donor route and just bags them up with the seperate part numbers anyway. I suppose they could be wound with a different sensing coil handedness - but i doubt it. No difference in connector keying either.

 

[avanti]

1) - Yep.
2). - Yep different part numbers (MB, Bosch, and Holstein). I believe rock auto gave the lengths for the bosch units. When I hold my Holstein rears side by side they are identical except for the part numbers. So maybe they (holstein) went the universal donor route and just bags them up with the seperate part numbers anyway. I suppose they could be wound with a different sensing coil handedness - but i doubt it. No difference in connector keying either.

It is the Holstein units that have lengths. Both sides are shown as 1600mm which is like 5'.

The fact that the fronts are the same on both sides is further evidence that there is likely no directional difference in the actual sensors.

I'd probably spring for the Boschs if I could figure out which one had the longer cable.

 

[rollerbearing]

Important new learnings - some of these sensors may have been coil type and they have evidently changed to hall effect type sensors. Thanks to showkey!

FYI......The tone ring is built into the bearing/seal.
The sensor will not develop a voltage when turning the wheel, it acts more like a switch and has a voltage applied from the control and passes the voltage as the wheel spins. So to measure sensor voltage while turning the wheel all the wiring would need to connected.

Wiring compromised down stream from the control unit or upstream From the sensor back ???????

View attachment 116986

Dennis/LindenEngineering posted a VERY! helpful tutorial over in the NCV3 forum:

First
Doing the knowledge:-
https://www.picoauto.com/library/automotive-guided-tests/abs-speed-sensor-digital/

Next with a sensor in place, if you have a scanner with live data look at the wave form/frequency. If you are unsure of the wave form frequency check one of the good functioning channels (say the front axle) and compare.

If you have no signal on a channel go back to the harness break in front of the r/axle and check for a 5 volt volt reference signalling on one of the pins and then check the ground.
If you have an interruption /high resistance of more then 0,03 ohms , and remember these two wire harnesses collectively run along the chassis before terminating at the ABS brick/module./

Visually look for open harnesses, burning exhaust, inner fender panels having cut through the harness are all part of a successful repair. (OHM OUT THE HARNESS WITH A DVOM.)

These are the most common areas of problematic communication on Sprinters
Go for it !
Dennis

Most importantly the Picoscope article says to never ohm out the sensor itself unless you absolutely know it is of the coil type. Ohming out a hall effect sensor risks damaging it.

 

[codycat]

On our 2020 winter trip from Washington State to Tucson and back up the Pacific Coast we had all four wheel speed sensors fail within a 9 day period. We have a 2015.5 Unity with a murphy bed. The 100,000 mile / 5 year warranty expires this coming March so, as much a pain as it was, all four sensors were thankfully replaced under warranty.

The ABS/ESP warning lights came on in Sedona, AZ and, being on vacation, I did not head for the nearest workshop. A couple days and a few hundred miles later the transmission began to shift erratically. So much so I was concerned about damaging the transmission. It was a two-hour tow back to MB in Peoria, AZ.

Having read this forum I knew the driveline needed to be disconnected and luckily had the tools to do it (which the tow truck driver did not). MB recommended replacing the four bolts, which they did.

The Right Rear Wheel Speed Sensor was replaced in Peoria. MB part # 906 905 11 01.
The Left Rear Wheel Speed Sensor was replaced in Tucson. MB Part # 906 905 10 01.
The Left Front Wheel Speed Sensor was replaced in Bakersfield. MB Part # 906 905 06 01.

On a hunch I had them order in two front wheel sensors, one of which I paid for.
The Right Front Wheel Speed Sensor was replaced in Stockton. MB Part # 906 905 06 01 and Cable Tie 002 997 24 90 64.

Having already purchased the part we saved the time it would have taken for them to run up to Sacramento to get one. I bought the part at retail and sold it back to MB at wholesale. Saved some time and lost a little money on that one but got back on the road.

Regarding extended warranties. I read it can still be purchased while currently under warranty, which we are. Is it worth it?

Thank you for any responses regarding extended warranties.

 

[avanti]

Regarding extended warranties. I read it can still be purchased while currently under warranty, which we are. Is it worth it?

Thank you for any responses regarding extended warranties.

Every MB extended warranty that has been posted has been an "inclusionary" warranty that only covers listed items. None of them has listed wheel sensors or ANY part of the emissions system. Lots of people don't believe this because it seems so crazy. But it is right there in black and white, as a quick search will demonstrate.

I won't say that these warranties are worthless, but they don't cover any of the frequent-failure items on Sprinters. Not a good value.

 

[SSTraveler]

You don't mention the cost but if the extended warranty doesn't cover these items you are probably wasting your money. As the items on the Emissions Warrany, covered for 5 year, list are probably the next most likely things to fail. I had my NOX Sensors and DEF heater fail at 44,000 miles and 1 week shy of my 5th year anniversary. Fortunately, MB covered the $2500+ cost of the repair. IMHO, extended warranties are a waste of money, but it certainly would have to be a bumper to bumper full coverage warranty to truly give peace of mind if one is willing to pay for that. If memory serves the Exhaust Gas Recirculation system (EGR) has been extended to 100,000 miles and no time frame.

 

[Myolblu]

During a trip over to have my driver air bag recall take care of, my ABS alarm came back. They replaced the faulty sensor. The mechanic & the Sprinter service manager said what many have indicated here. They only replace the bad sensor and send you on your way. He indicated that they see the problem in dual tire Sprinters built in 2015 & 2016. I got the opportunity to talk to the mechanic privately later. He said it's a big batch of wheel speed sensors used during those years of production and MB is in denial hoping you'll be out of warrantee before the failures occur. He said the DEF system is causing them lots of problems along with biodiesel. Water emulsifies in bio and rusts up the fuel system internally. I asked about the 2019 Sprinters. He said he likes what he sees but that it's too soon to make a determination. He told me he would never buy anything new & improved that MB rolls out without it being time tested. He left them once in the 90's due to some poor reliability issues. The San Antonio Sprinter service center is one of the good ones. From what I have experienced, they do not try to rack up unneeded work & costs. They are thorough and courteous and strive to give you the very best service period.

Myolblu here. just joined. my 2016 Sprinter has also had speed sensor problems/replacements. It is frustrating. When the last one went out and my mechanic replaced it, he soldered the wires instead of using the connector. He feels the connector gets loose which makes the contacts make and break contact causing the problem. So far, that has solved the problem of the idiot lights coming on the dash etc.

 

[avanti]

OK, I have a bit of somewhat surprising data:

Deciding that I have had enough angst concerning the rear wheel sensor failures, I threw in the towel and bought a spare set both rear sensors from my Dealer, to carry as spares. Conventional wisdom on the list says that these items are identical except for cable length. I have been asking and asking whether anyone knew which one was the longer, thinking that I could use it on either side. Nobody could tell me. Now I know why. THEY ARE EXACTLY THE SAME LENGTH! The sensors themselves also appear to be identical. And yet, they have different part numbers and the plugs are key'd differently.

So, how could this be? It would seem that the sensors are NOT identical, else why would they have different numbers and different keys? So, this is a bit of a mystery. If they were just simple hall sensors, there should be no difference side-to-side. I can only think that they are somehow more elaborate. Perhaps they are capable of reporting rotation direction as well as speed.

I guess the other possibility is that they ARE identical except for the keys, and the intent was to prevent crossing left and right. Pretty strange.

At any event, you CANNOT buy just one of these to serve as a spare for both rear wheels, at least unless you are prepared to splice wires.

Here are some pics:

Note that although the plastic has the same number molded into it for both pieces, the right-hand sensor (shown on the left) has a little round dimple molded into it.


The wire for the Left hand sensor has a big white stripe on the wire, on the other side from the part number.

 

[Deleted member 50714]

Are you familiar with the training documents.

http://diysprinter.co.uk/reference/Sprinter-Tech-Overview-2000-2010.pdf