W211 2006 e320 resetting brakes - no gap between front pads and discs

[SA1]

Hi,

I also double checked the RHS back sensor again by jacking up the back wheel and moving it by hand and again got zero rpm on the ESP menu. I checked the resistance of the two rear speed sensor leads leading to each hub carrier, and got 9M ohms for each (same as fronts as I recall), and then checked the wiring into which each sensor was plugged. I got 6M ohms for the LHS (the side which was giving me rpm values and which I knew was Ok when previously checked, as above) but when I checked the RHS I got 0 ohms.

Now I'm thinking that I either have a break in the wiring leading to the ECU (presuming that's where it eventually ends up), or that it's a fuse which has gone. I have identified fuse 47 which is for ESP, SPS and BAS control unit and 79 which is the rear SAM control unit with fuse and relay module as possibilities, though I guess the fuse would be for all the sensors and if it went, then would that affect more than one of the sensors?

 

[onefortheroad]

was this problem there before you did any work on this vehicle ?

 

[SA1]

was this problem there before you did any work on this vehicle ?

Checked the 2 fuses which looked ok. To recap, front wheel sensors Ok (ones I did wheel bearings), LHS rear sensor reading OK, RHS rear sensor reading zero.

I assume the problem wasn't there before I worked on the car, otherwise it would have set off my ABS light previously due to getting zero for the rear RHS wheel speed. As I say I swapped the rear sensors and they both worked on the LHS rear wheel with output of about 6M ohms which is normal for active sensors. I got similar reading for the harness into which the sensor plugs in on the LHS, but no reading on the RHS (or on wear sensor harness - which is part of the same harness - the part which holds both plugs), so suspect it is something to do with the wiring to the SBC or the ESP. Also SPC and ESP comes up 50% when I carry out diagnostic on each menu (can't remember if that's normal). No fault codes to help me, apart from that previously mentioned.

Wondering whether I should take the SBC control module panel off to check the soldering/wiring as each of L6/1,2,3,4 all feed into it - although I am a bit reluctant. On the other hand removing it and giving it a clean and refitting it might be a help (maybe reboots it, but I'm guessing).

Reluctor wheel looks ok when I looked down the hole where the wheel sensor goes. I guess it could be the magnetic ring on the wheel bearing, but I think to happen now is too much of a coincidence, but you never know as my car has done 190K.

 

[SA1]

Hi everyone,

I carried out another scan with my scanner and noticed that on the ESP sensor menu if I look at the steering angle sensor and turn the wheel clockwise I get reasonable values of 1 degrees and slight continuous movement increments of these values as expected, but turning anticlockwise from 0 degrees I get 6551 degree and other unusual incremental values.

If I go to the menu for steering column module, steering wheel position and alter the steering angle by rotating the steering wheel, I get normal degree values in each direction. I suspect this is why I am not seeing any error codes.

When I try driving above around 5mph I get the flashing yellow triangle and an error for ABS 6210. I understand that this is commonly due to faulty steering angle sensor or faulty SBC harness (ABS control module) (I have now ruled out the speed sensors) or losing the signal from the rear wheel to the module. The angle sensor could be a possibility from what I have just mentioned in the first paragraph, and also I have had an advisory on my last MOT concerning high beam switch flickering and also experienced problems with indicators - turning the wrong direction eg. clicked right and the opposite happened or didn't do anything. As this only happened a couple of times in the last 9 months I hadn't replaced anything, but I am now wondering whether it could be linked to this. But either way, would replacing the angle sensor in the steering wheel have any affect on the rear RHS wheel zero speed mph value? - I would think not, but I'm not an expert.

I am thinking it's something to do with the wiring from the SBC module to the point at which the sensor plugs into the harness (onward from there is OK), but I am unsure how to test for that. If I disconnect the SBC harness what electric checks could I perform and how ? Disconnect the 2 batteries first I guess.

Getting to think I might have to get someone with Star before paying for items (although steering wheel sensor is relatively cheap and is there because of having ABS so might be an idea to replace) and could drive to dealer after removing ABS fuse, but would really like to sort this myself - but been on this for weeks now, so getting desperate for help.

 

[Botus]

my bit about spinning the wheel was aimed at fronts in that instance.. the hand brake is at the back so on RWD car the fronts should spin freely and almost keep going for a good few turns (depending how enthusiastically you spin the wheels)

if the diff is free and the oil warm you could get the rears to spin a bit, but having done the fronts one should get the idea of what's going on at the rear (and anyway there's often some slop allowing the wheel to move a few degrees before all the rest of drive train gets interested in making it hard work) - thus sticking brakes are pretty obvious... usual caveats FWD RWD 4WD, hand brake the wrong end (a Citroen favorite) LSD meaning the prop shaft need to go round, dodgy handbrake etc.

to your latest point...

its not unheard of for the "clock spring" to go wrong (nasty name for the ESP steering angle wiring /sensor)
broken wires in the ABS speed sensors ought to be common as they take a battering with wheel movement / high miles and terrible roads
DTF ABS sensors (not the wiring element), are normal on Mercedes
DFT ABS modules, are standard on most brands, but weirdly appear rare on Merc
Soggy electrics, std on a Merc
Mad can bus as a result of soggy electrics, std on a Merc
SAM gone pop, quite common on Mercs

 

[SA1]

my bit about spinning the wheel was aimed at fronts in that instance.. the hand brake is at the back so on RWD car the fronts should spin freely and almost keep going for a good few turns (depending how enthusiastically you spin the wheels)

if the diff is free and the oil warm you could get the rears to spin a bit, but having done the fronts one should get the idea of what's going on at the rear (and anyway there's often some slop allowing the wheel to move a few degrees before all the rest of drive train gets interested in making it hard work) - thus sticking brakes are pretty obvious... usual caveats FWD RWD 4WD, hand brake the wrong end (a Citroen favorite) LSD meaning the prop shaft need to go round, dodgy handbrake etc.

to your latest point...

its not unheard of for the "clock spring" to go wrong (nasty name for the ESP steering angle wiring /sensor)
broken wires in the ABS speed sensors ought to be common as they take a battering with wheel movement / high miles and terrible roads
DTF ABS sensors (not the wiring element), are normal on Mercedes
DFT ABS modules, are standard on most brands, but weirdly appear rare on Merc
Soggy electrics, std on a Merc
Mad can bus as a result of soggy electrics, std on a Merc
SAM gone pop, quite common on Mercs

Hi Botus,

Thanks for your comments. I am beginning to think that I should have saved a bit more money to buy 2007-2008 model instead of my 2006 with SBC - maybe electrics might have been better on these later models as well?

I think the time has come for me to admit defeat after trying to solve this situation for the past few weeks, and get the Mercedes dealership involved in the hope that their experience as well as their more comprehensive Star diagnostic might pinpoint something which I have missed.

I will respond next time to let you know what they find, out of interest value and to help others who may come across similar situations.

 

[Botus]

any good merc idie will probably know more about cars this age and charge 1/3 of the price,

 

[alexanderfoti]

any good merc idie will probably know more about cars this age and charge 1/3 of the price,

+1 find an indy. They will likely fix it quicker than a dealer and charge you less. Win win!

 

[John Laidlaw]

As said
http://www.mercedesspecialistfinder.co.uk/search/?postcode=CB3+0AL&category=14&distance=25

 

[SA1]

Thanks everyone - I took your advice and found a friendly and very helpful guy from the link provided by John. The mechanic even offered to come to my property for a small addition charge to make it easier for me when I mentioned that I would have to arrange a low loader to get the car to him.

 

[John Laidlaw]

Thanks everyone - I took your advice and found a friendly and very helpful guy from the link provided by John. The mechanic even offered to come to my property for a small addition charge to make it easier for me when I mentioned that I would have to arrange a low loader to get the car to him.

Excellent good luck

 

[SA1]

Hi everyone,

The mechanic came but unfortunately his diagnostic machine revealed no more than I already knew. He suggested that he could download some electrical diagrams and have a further look, but that would mean getting my car down to him and I would probably have to pay for a low loader to take me there which is going to be £100.
So I am thinking to have a further look myself so that I don't have to pay this cost - does anyone know where I can download specific wiring diagrams for a small cost?
Does anyone have experience of diagnosing electrical problems using wiring diagrams?
Thanks.

 

[Botus]

Hi everyone,


The angle sensor could be a possibility from what I have just mentioned in the first paragraph, and also I have had an advisory on my last MOT concerning high beam switch flickering and also experienced problems with indicators - turning the wrong direction eg. clicked right and the opposite happened or didn't do anything. As this only happened a couple of times in the last 9 months I hadn't replaced anything, but I am now wondering whether it could be linked to this. .

not sure I'd seen this bit previously

dodgy earth, sam and or canbus fun?

 

[Steve@Avantgarde]

So..

I've read most of this and to briefly recap, you have an ESP light on and no signal on live data to O/S/R wheel and the same if the sensors are swapped left to right? So effectively that proves your sensors are good.

Knowing these cars like I do I would say that half of the pick up ring on the driveshaft has corroded away and the sensor can't pick up the reading. You can buy the multipole rings from MB for about £10. You do have to remove the driveshaft though which makes it a 4 hour job.

Any form of ESP fault will really upset the SBC, especially if pistons were pushed back in the callipers without the SBC deactivated. You should be able to scope the sensor anyway and see if its picking up any signal from the ring.

 

[SA1]

So..

I've read most of this and to briefly recap, you have an ESP light on and no signal on live data to O/S/R wheel and the same if the sensors are swapped left to right? So effectively that proves your sensors are good.

Knowing these cars like I do I would say that half of the pick up ring on the driveshaft has corroded away and the sensor can't pick up the reading. You can buy the multipole rings from MB for about £10. You do have to remove the driveshaft though which makes it a 4 hour job.

Any form of ESP fault will really upset the SBC, especially if pistons were pushed back in the callipers without the SBC deactivated. You should be able to scope the sensor anyway and see if its picking up any signal from the ring.

Hi Steve,

Yes, the first paragraph is correct.

I tried to visual inspect the toothed impulse ring and the condition looked the same as for both rears as far as I could tell (please see the attached image and tell me what you think).

I made sure that the pistons were pushed back into the calipers with the SBC deactivated.

I was thinking about buying some long leads to connect to the LHS rear sensor harness connector (under the LHS wheel arch) to the connectors of one of the rear speed sensors attached to the wheel on the RHS and if I don't get a reading for mph, then it's likely it's the impulse ring and if I get reading then I must assume that I have an electrical fault.

As it's probably difficult to get a wire to stay attached at the LHS harness I was even thinking of buying a cheap second hand rear speed sensor and cutting the wires and then getting a lead to connect to the RHS rear sensor. Any suggestions on that?

Thanks.

 

[SA1]

Hi Steve,

Yes, the first paragraph is correct.

I tried to visual inspect the toothed impulse ring and the condition looked the same as for both rears as far as I could tell (please see the attached image and tell me what you think).

I made sure that the pistons were pushed back into the calipers with the SBC deactivated.

I was thinking about buying some long leads to connect to the LHS rear sensor harness connector (under the LHS wheel arch) to the connectors of one of the rear speed sensors attached to the wheel on the RHS and if I don't get a reading for mph, then it's likely it's the impulse ring and if I get reading then I must assume that I have an electrical fault.

As it's probably difficult to get a wire to stay attached at the LHS harness I was even thinking of buying a cheap second hand rear speed sensor and cutting the wires and then getting a lead to connect to the RHS rear sensor. Any suggestions on that?

Thanks.

So..

I've read most of this and to briefly recap, you have an ESP light on and no signal on live data to O/S/R wheel and the same if the sensors are swapped left to right? So effectively that proves your sensors are good.

Knowing these cars like I do I would say that half of the pick up ring on the driveshaft has corroded away and the sensor can't pick up the reading. You can buy the multipole rings from MB for about £10. You do have to remove the driveshaft though which makes it a 4 hour job.

Any form of ESP fault will really upset the SBC, especially if pistons were pushed back in the callipers without the SBC deactivated. You should be able to scope the sensor anyway and see if its picking up any signal from the ring.

Hi Steve,

Looks like you were correct - just had news from the Merc independent mechanic who told me that the ring wasn't moving, which means it is probably corroded and snapped inside the driveshaft, as you suggested. I guess the visual inspection which I made is not good enough to gauge the ring condition and what I should have done was to also spin the hub whilst watching to see if the ring also moved round - at least I know what to look for now if it happens in a car I get in the future.

I was quoted about £450 to do this job, and was wondering if you could tell me the steps I need to do to carry out the work if I decide to do it myself, as you have done these jobs yourself? How complex is the job - I am just working under a carport. Do I have to remove the driveshaft?

Thanks

 

[Wighty]

Hi Steve,

Looks like you were correct - just had news from the Merc independent mechanic who told me that the ring wasn't moving, which means it is probably corroded and snapped inside the driveshaft, as you suggested. I guess the visual inspection which I made is not good enough to gauge the ring condition and what I should have done was to also spin the hub whilst watching to see if the ring also moved round - at least I know what to look for now if it happens in a car I get in the future.

I was quoted about £450 to do this job, and was wondering if you could tell me the steps I need to do to carry out the work if I decide to do it myself, as you have done these jobs yourself? How complex is the job - I am just working under a carport. Do I have to remove the driveshaft?

Thanks

Can't help with advice buddy , but what about a Haynes manual for your car model . You are probably going to have to read up from every source you can find

 

[EmilysDad]

.... Do I have to remove the driveshaft?

...

Yes.

 

[SA1]

Hi All,

After not getting readings on my offside rear speed sensor I decided to replace the magnetic tone ring located on the driveshaft. After unscrewing all the bolts which hold the wheel hub to the suspension parts (not easy), I used a hub puller to remove the hub. I managed to do this without having to remove the driveshaft which seemed like it might be a much bigger job.

I replaced the old corroded ring with a new one and once I had but everything back together I got readings from the wheel. However, I still got an ABS light coming up even after resetting the faults. At a loss of knowing what to do next I took it to the Merc dealership thinking their expensive Star diagnostic would give me more detail on this persistent fault. The only thing was rear RHS wheel speed sensor, which wasn't much good to me. I drove the car back home and replaced the sensor with a new one anyway, but still ABS light on.

I then let my local independent specialist deal with it as his labour rates were half what the dealership wanted. He stripped it down and found that the speed sensor rotor was not moving when the wheel turned (which is what he had originally found some weeks previously before I changed the tone ring). and that a road test found incorrect speed from the right rear sensor.

Any help would be greatly appreciated as I am wondering whether to carry on with the car (2006 E320 190K miles - maybe worth £1500?) or have one last strip down of the car.

Thanks.

 

[SA1]

Hi everyone,

Apologies for not writing this up much earlier.

A few months ago I finally figured out what was wrong with my car. I couldn't understand why I was still getting a different reading on the RHS wheel sensor as compared with the other sensors which were reading the same as each other. I decided to look down the sensor hole myself with a bright torch and move the hub (I set up a camera on video on a tripod so my hands were free to move the hub, with the car in neutral), and see for myself that the RHS sensor ring was not moving (video file too big so see pic 1). I confirmed that the sensor appeared not to be moving.

I then decided to take off the hub carrier again (pic 2) and found that although I had fitted the new ring OK, and that I had cleaned this area before ring fitment, I had forgotten to clean the hub carrier part which slots into the driveshaft end (pic 3). I could then see, as in the pic, that the sensor was blocked. The blockage was caused by the backing plastic film which must have fell off the old rusty sensor ring (pic 4) and covered the sensor hole (which was why I never saw any movement of the actual sensor ring because the film was covering it).

The blocked sensor hole was the reason why I was seeing a different reading on the RHS sensor as compared with the other 3 sensors, with the result that the ABS (and ESP error) light would go on when I drove the car.

After removing the old sensor backing film and cleaning the blocked sensor hole and that whole area, I put everything back together (which took a while) and took the car for a test run. Finally, no more ABS light or errors shown on the dash!
Having earlier contemplated selling the car it was such a relief to know that I had finally fixed it, (especially when the Merc garage were advising me to pay 2-3 hours labour to look into potential electrical faults, and also wanted nearly £200 parts+labour just to put on a new RHS wheel sensor). Glad that I didn't sell the car - for a 13 year old car with 190k it still drives great!

All the best.