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No issue living with the warning light as it’s a winter car that will not be driven until the fall. My issue is finding the correct part which I am certainly having issues locating
Originally Posted by andreigbs
You'll have to live without a brake wear sensor on the rear, along with a warning light on the dash until you replace.
You could try soldering the wires back together and some heat shrink tubing. A solder set is $15, $3 for shrink tubing, fixed for under $20.
Any suggestions? This is my 2010 GLK 350 4 Matic 170K miles. Dealer mechanic at first instinct says ABS Speed Sensors is culprit. Vehicle drives fine, with no issues with power steering or brakes. Cruise Control inoperative. I have 2 new FRONT ABS Speed Sensors on order - can someone point me on guidance on speed sensor replacement?
Have you scanned the car for any codes? Speed sensors sometimes just need a good cleaning with brake parts cleaner, they get gunked up with brake dust and other muck. Replacing them should just be a relatively easy unplug-old-plug-in-new procedure. I would look around the hub.
I replaced all the brakes and new wear pad sensors. This took care of the brake pad wear error on the dash as that's now gone. My code reader told me the right rear speed sensor was gone so I replaced it, cleared the code then took the car out with a clear dash no lights. I got about 50 feet and the lights all came on again, Ran the code reader again which then told me the left rear is an issue. I replaced the left rear speed sensor cleared all the codes and had a nice clean dah with no lights. I drove 50 feet and it xmas again the dash is all lit up. I run the code reader again and it tells me D40C Right rear wheel speed sensor, DB40B Left rear wheel speed sensor. Not sure what to do next to figure out whats on the go with this car. Anyone has any suggestions please let me know currently the car is not drivable as its in limp mode.
I replaced all the brakes and new wear pad sensors. This took care of the brake pad wear error on the dash as that's now gone. My code reader told me the right rear speed sensor was gone so I replaced it, cleared the code then took the car out with a clear dash no lights. I got about 50 feet and the lights all came on again, Ran the code reader again which then told me the left rear is an issue. I replaced the left rear speed sensor cleared all the codes and had a nice clean dah with no lights. I drove 50 feet and it xmas again the dash is all lit up. I run the code reader again and it tells me D40C Right rear wheel speed sensor, DB40B Left rear wheel speed sensor. Not sure what to do next to figure out whats on the go with this car. Anyone has any suggestions please let me know currently the car is not drivable as its in limp mode.
Ok fearing I may of had two bad (new) sensors and they were the cheap ones from Rockauto I went to NAPA and bout the expensive ones. Installed them and still same issue. I then took the time to measure the resistance of the new expensive ones and compared that to the new cheap ones and it was exactly the same. I then connected my muitmeter to the plug in for the sensor as in where the sensor harness plugs into the car to see if there was any power there and I get 11 volts on both sides so I am now assuming there is no issue there. I then connected the multimeter to the sensor plug with it installing in the hole for the sensor and then spun the wheel but I get no signal or voltage from either wheel. So now I am wondering my next step...… Please guys anyone has some help here it would be greatly appreciated
Yikes, sounds like you're having no fun. Hang in there. It seems as though you've determined that both sets of rear wheel speed sensors (cheap and not so cheap) seem good, so the problem may lie elsewhere. The wheel sensors must send their individual signals to a control module, so perhaps that's the culprit.
Not knowing exactly what brand of sensors you got, it IS possible the control module may not recognize the signal or not like the signal it's getting. I'd hate to tell you to buy new wheel speed sensors yet again, this time from your dealership or an OEM parts place, but that MAY be a necessity if the control module itself checks out.
Do you really think that may be the issue as in the signal from both brands being the issue?? I am leaning towards a wheel bearing issue as it appears that this can cause the same issue or so I am reading but honestly I am at a loss as to what to do next. I am not convinced that the voltage is correct coming from the car as in when tested from the plug that the sensor connects to leading up to the abs control module. I am thinking of taking the hub apart but certainly its a big undertaking really love any and all advise from anyone who has been here. I know I am getting no signal from the wheel speed sensors on either wheel with the multimeter when spinning the wheel which has me thinking its an issue with wheel bearing or the magnetic wheel/sprocket its just hard to believe both are an issue so I am just scratching my head. Anyone reading this I would love your thoughts and suggestions to help conquer this.
The NAPA ones were overpriced. The OEM ones I linked above are $66 each. I can't speak for the cheapy ones, but I'd be surprised if they functioned the same as OEM or last as long. Your mileage may vary. Hopefully someone else can chime in, but until then...
I don't think it's a wheel bearing issue, that is more of a mechanical item and you'd have other symptoms if they were both bad, and unlikely at the same time. You can test bearings out by pulling on the tire/wheel alternately on opposite sides looking for play. I doubt it's the hub itself either, unless you have a bunch of gunk build-up. I assume you looked carefully when replacing the brakes and used good amounts of brake parts cleaner in the process.
You may be experiencing ABS module failure, and this is not uncommon. You might want to read up on that issue. New ones are about $930 (here) but you may be able to find one from another car to swap, that way it wouldn't require you going to the dealer to have it coded.
Thanks for your response! I agree with it not being a bearing issue and the only reason I thought it may be the bearings was that I was unsure is the magnetic part that the speed sensors get their reading from may of been part of the bearing as it is in many vehicles. I have since learned in certainly is not but its a wheel/ sprocket like thing on the axle. I spoke with a mechanic today at the dealer and he said its very unlikely if the front sensors are working fine that the module is the issue. He was very confident that this was an issue with what he referred to as the reluctor ring which is on the axle. He said as we have snow and salt on our roads in winter its the most common reason for these type issues. When I told him I had the sensor placed in the hole and attached and the wiring harness connected to my multimeter and spun the wheel with no signal that really narrowed the issue. I am going to replace those reluctor wheels and see if it fixes the issue.
Again thx for your help I really appreciate it and if anyone else has any suggestions/ comments I would love to hear them.
Sounds like you're on the right track. Did some reading on "reluctor rings" and your mechanic may be right. Hopefully that resolves your issues, let us know!
Ok problem is finally solved and I have to share the issue and the solution for any poor souls that encounter the same issue. My car is a 2012 Mercedes GLK 350 4matic.
My wife comes home one day and tells me the dash is lit up like a Christmas tree. I has EBD ABS and traction control errors. Spoke to my mechanic and he said its likely a wheel speed sensor but he does not usually work on Mercedes so his code reader was no good for that car. He tried it but sure enough it was no good for my mercedes
So I said the hell with it came on this group asking for what code reader would be good and I purchased it. It is the icard MB II and it works great. Ran the code reader and sure enough it told me the right rear speed sensor was not sending a signal. So I went online trying to find some decent priced ones which I found at Rockauto.com they were like 30 bucks each. I replaced the right rear which is very simple to do. Put you car on a jack then remove your wheel. You will find one small bolt that's a torx bolt not sure the size but if anyone needs to know I can check it. Remove the bolt then very carefully wiggle the sensor out of the hole. Be careful as they can be in there very snug and I was not with one and had it snap off and was a good while getting the hole cleaned out. Next you remove the fender skirt. This is just a few nuts and a few plastic plugs. The plastic plugs you take a small flat head and wiggle out the centre plastic nail not totally out but out a bit then plug the rest of it out Remove the skirt and you will find there the other end to the sensor is...it plugs in up under the wheel well. There is a meta clip that holds the sensor in so you will need to remove that. Remove the old one and do all the steps in reverse. No need to reset the codes all will happen on their own once the computer gets the signal from the sensor.
I replace the right rear sensor put all back together and then bring the car out. Errors are still there and now the car goes into whats called limp mode. This apparently is a protection thing that many European cars use to protect itself from damage whereby the car will not go over I believe its 20 kms per hour. Not knowing what this meant at the time I was very concerned. I resent the codes with my code reader only to realise then I had both rear sensors reading that they were faulty. Now I was confused and worried. I put the car back in the garage and then headed back online. Most I read indicated possibly the cheap sensors were the issue. So I went out and bought the expensive ones locally that were $376. 00 for two . Ran back to the garage installed these and then tested the car but again same issue. I returned the sensors for a refund and then scratched my head as to what to try next. So I read somewhere about testing the voltage from the plug that the sensor plugs into up to the abs control sensor. So I get my multimeter and connect the alligator clips to the two pins that I pop in the holes and I get 11 volts. Same on both sides so I was guess this was all good. I then put the sensor in the hole that it supposed to be in and I spin the wheel with the other end of the sensor connected to my multimeter. I get nothing from each wheel. No signal at all and from what I read online I should get very low voltage. So now I have to figure out what creates the signal on the wheel/axle to send to the sensor which is then sent to the ABS control module. Its called a reluctor ring.
This little fella is attached to your axle and as the axle spins its magnetic and sends the speed at which the axle is turning to the wheel speed sensor. So I thought this must be my issue. So I began taking **** apart as in the wheel first then the brake caliber bracket the brake caliper etc. Had to let go upper and lower control arm etc. Slid axle out then removed the ring well actually one fell apart the other was not better.
Put it all back together and tested the car. All lights went out and the car went out of limp mode.
The ring issue was a big job replacing them removing the axle was not too bad but getting the suspension back together was brutle.
Anyway if anyone is having issues like this one with these lights. I would first scan with a good code reader that tells you which one is gone. Easy quick job is to replace the sensor but if that does not fix the issue the rings may be your problem especially if you are in a climate like we are here in Newfoundland with snow ice and salt on our roads. If I can help anyone with this process please contact me as this was difficult with little to no help and I will help. trlee32@hotmail.com
Awesome work, well done good sir! Just for fun, I’d call the dealership for a quote to see how much they’d charge you for that job, then pat yourself on the back for saving a good chunk of change. It’s likely this is the first and only time you’ll need to replace those rings.
Enjoy the car car out of limp mode now! The code reader will come in handy for the rest of your ownership experience.
Thx I am happy its fixed and I will admit not knowing with certainty that this was the issue I was nervous tonight when testing it. I knew if it was not that I had really ran out of things to try besides finding a Mercedes specialist and the possible solutions were very expensive as in control module or wiring issue. Anyway its all done now well not totally I still have to reinstall the fender skirts and adjust the torque settings on the suspension.
Ok problem is finally solved and I have to share the issue and the solution for any poor souls that encounter the same issue. My car is a 2012 Mercedes GLK 350 4matic.
My wife comes home one day and tells me the dash is lit up like a Christmas tree. I has EBD ABS and traction control errors. Spoke to my mechanic and he said its likely a wheel speed sensor but he does not usually work on Mercedes so his code reader was no good for that car. He tried it but sure enough it was no good for my mercedes
So I said the hell with it came on this group asking for what code reader would be good and I purchased it. It is the icard MB II and it works great. Ran the code reader and sure enough it told me the right rear speed sensor was not sending a signal. So I went online trying to find some decent priced ones which I found at Rockauto.com they were like 30 bucks each. I replaced the right rear which is very simple to do. Put you car on a jack then remove your wheel. You will find one small bolt that's a torx bolt not sure the size but if anyone needs to know I can check it. Remove the bolt then very carefully wiggle the sensor out of the hole. Be careful as they can be in there very snug and I was not with one and had it snap off and was a good while getting the hole cleaned out. Next you remove the fender skirt. This is just a few nuts and a few plastic plugs. The plastic plugs you take a small flat head and wiggle out the centre plastic nail not totally out but out a bit then plug the rest of it out Remove the skirt and you will find there the other end to the sensor is...it plugs in up under the wheel well. There is a meta clip that holds the sensor in so you will need to remove that. Remove the old one and do all the steps in reverse. No need to reset the codes all will happen on their own once the computer gets the signal from the sensor.
I replace the right rear sensor put all back together and then bring the car out. Errors are still there and now the car goes into whats called limp mode. This apparently is a protection thing that many European cars use to protect itself from damage whereby the car will not go over I believe its 20 kms per hour. Not knowing what this meant at the time I was very concerned. I resent the codes with my code reader only to realise then I had both rear sensors reading that they were faulty. Now I was confused and worried. I put the car back in the garage and then headed back online. Most I read indicated possibly the cheap sensors were the issue. So I went out and bought the expensive ones locally that were $376. 00 for two . Ran back to the garage installed these and then tested the car but again same issue. I returned the sensors for a refund and then scratched my head as to what to try next. So I read somewhere about testing the voltage from the plug that the sensor plugs into up to the abs control sensor. So I get my multimeter and connect the alligator clips to the two pins that I pop in the holes and I get 11 volts. Same on both sides so I was guess this was all good. I then put the sensor in the hole that it supposed to be in and I spin the wheel with the other end of the sensor connected to my multimeter. I get nothing from each wheel. No signal at all and from what I read online I should get very low voltage. So now I have to figure out what creates the signal on the wheel/axle to send to the sensor which is then sent to the ABS control module. Its called a reluctor ring.
This little fella is attached to your axle and as the axle spins its magnetic and sends the speed at which the axle is turning to the wheel speed sensor. So I thought this must be my issue. So I began taking **** apart as in the wheel first then the brake caliber bracket the brake caliper etc. Had to let go upper and lower control arm etc. Slid axle out then removed the ring well actually one fell apart the other was not better.
Put it all back together and tested the car. All lights went out and the car went out of limp mode.
The ring issue was a big job replacing them removing the axle was not too bad but getting the suspension back together was brutle.
Anyway if anyone is having issues like this one with these lights. I would first scan with a good code reader that tells you which one is gone. Easy quick job is to replace the sensor but if that does not fix the issue the rings may be your problem especially if you are in a climate like we are here in Newfoundland with snow ice and salt on our roads. If I can help anyone with this process please contact me as this was difficult with little to no help and I will help. trlee32@hotmail.com
First off, I just wanted to say thank you to everyone on this forum for saving me the cost of a replacement transmission/transfer case.
A bit of back story:
I got my 2015 GLK 250 last year and was told it was out of warranty when I got it-it had 49,000 km (I'm in Calgary Alberta, Canada). It needed front pads and rotors when I got it, did that along with oil change, all air filters and fuel filter (pretty simple stuff, the car has been really easy to work on).
After a week and a few trips on the hwy I noticed a barely perceptible whine that sounded like it was coming from the transmission-sounded like it was coming from the center console or D/S footwell. Called up the dealer that I got it from, they basically said all deals are final blah blah blah. I started reading this forum and started worrying about the transfer case bearing issues... I took it to the mercedes dealer (Country Hills Mercedes-I HIGHLY recommend them) and got them to do a tranny flush and check it over for the sound. They called me up later that day and said my wheel bearings were bad. I said ok... how much is it going to cost me. They said NOTHING it is still under warranty for 2 more months! They did it, I got it back, the whine was still there, I brought it back, they couldn't replicate... At this point I was thinking it was going to be just like my Ford experiences where they never find the issue and I have to fix it myself to resolve the issue. But when I came to pick it up-I was about to lose it on them-they asked if I would like to, I could take it out with the shop foreman to show him the sound.
That was a first for me. Like I said above, when I had Fords before the dealerships always tried to make me feel like I was crazy and I just ended up getting fed up and fixing the issues myself (suspension issues, locking hubs etc.). I had already started looking for parts to pull apart the transfer case, pull the bearings and replace them-wouldn't have been fun but definitely possible.
So long story short, the shop foreman was awesome, he went out with me and I showed him the noise (happened when lifting off the throttle at 100 KPH and 122 KPH). He agreed that it was there and I dropped the car off a couple days later for them to go over with stethoscopes/microphone ears in different spots. They called me back and said a bearing is gone in the transfer case, they have ordered a new transmission and transfer case (like some of you mentioned-it is 1 unit) and they replaced my entire transmission and transfer case under warranty with less than a month remaining! It was at 55K km when they replaced it (I was doing a LOT of driving).
The GLK currently has around 79K km, and still working flawlessly.
Thank you again everyone, if I hadn't read this forum I wouldn't have been so pushy to get them to diagnose and fix the issue before my 2 months for warranty ended.
Last edited by R Tap; Apr 6, 2020 at 10:46 AM.
Reason: forgot title
I need to replace the thermostat on ny 2010 GLK 350 4matic. Any recommendations for brands? I found OEM available thru https://www.mynewbenzparts.com/. I 'd appreciate reading about your experiences and if you have other recommendations. I prefer to buy better quality parts; I have found that to be cheaper in the long run.
Just replaced lower/upper control arms, tie rod ends, and F/R sway bar end links. All items lemforder except front end links which are Meyle HD since lemforder doesn't make end links for the GLK (at least not anymore, frustrating). Even after tightening the end links after a couple thousand miles, still small amounts of rattle over small bumps. Wish I just would of opted for OEM since they aren't that expensive (~$50). Alignment at Fletcher Jones of Newport for $200 (not bad honestly). At 200k miles, still rides exceptionally. Replaced fuel filter/sending unit as preventative. Lame that it's one unit. Motor/trans mounts about 10k miles ago. Might do rear shocks and mounts soon as I read this is a common issue and I do seem to have a nagging thud at low speeds in the rear. I feel like by the end of the year I'll have rebuilt the entire suspension but I just love the damn thing haha. Anyone have experience with rear suspension work? There's a plethora of rear control arms.
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2015 GLK 250 transfer case
