Speed sensor at left axle has a gap

[Kev555]

ESP and ABS lights came on last week on my 639 Vito. I replaced the ABS/Speed sensor yesterday with one from Mercedes but the Light is still on showing the same code after clearing the fault? Is it a magnetic wheel bearing? as theres no ring or seem to be any ABS reading markings in the bearing. Would i be right in suspecting the bearing? I did take the driveshaft partially out to blow out any dirt or debris but it was fairly clean. Old sensor was grew into it so it came out in bits. Any pointers appreciacated or did i miss doing something as regards software?

 

[LostKiwi]

If the air gap 8s more than 1mm it won't give a reading.
Not sure if yours is magnetic or not but 8s so it's the oil seal has the magnet. Magnetic ones tend to have the abs sensor in line with the driveshaft. Ones that use a reluctor wheel are at right angles to the driveshaft. If the old sensor had been contacting the seal it's probably knackered the seal magnets.

 

[alexanderfoti]

If the code says "check gap" its likely the reluctor ring is corroded.

 

[star]

Genuine or aftermarket sensor, seen a couple of after market sensor which are different length.

 

[Kev555]

Thanks LK, AMF and Star
live data shows the sensor is working ok just said the gap is not ok. The sensor was a genuine from from Mercedes Star and the old one was giving the exact same symptoms. I will post the part numbers just theres a chance its wrong sensor I was given . I couldn't compare sensor tip lengths as the old one had to be removed in bits. I didn't see any resemblance of a reluctor ring AMF as first thing I checked for as heard they get rusty and corroded. I'm going to have to strip it again next week and I will take a closer look. Any bearings ive looked at online for my model theres only one type which has an integrated magnetic sensor. The magnetic seal in mine is metal and not a grease seal which is easier spotted LK I did see a Meyle bearing that looks the same as mine online .I think a wheel bearing is looking like the only cure atm according to info you guys posted Fault code attached

 

[alexanderfoti]

Yes, reluctor "ring" is built into the oil seal, There is a rubberized black side, can be checked with magnetic paper. do you have abs/esp warnings or just this code?

 

[Kev555]

Yes Alexander I have ESP and ABS lights on instrument cluster, in live data all is ok except for gap. The sensor is reading speed ok and forward motion

 

[alexanderfoti]

Yes Alexander I have ESP and ABS lights on instrument cluster

I would think that live data must be sporadic and jumping if it is reading something

 

[Kev555]

Added to above post Alexander, MPH is reading smoothly and same speed as other rear sensor? I will double check it again tomorrow.

 

[alexanderfoti]

Then pass, needs some thing more in depth than I car soft. Logging all 4 while driving and graphing them should pickup which is sporadic. Could just be that fault code causing the esp error but I have never seen that code with a sensor that's working.

 

[Kev555]

I will try my other laptop with better software. thanks for the pointer. Do you think it could be another sensor and not the one the icarsoft is logging as faulty? Just to be clear rear left sensor is the nearside/passenger side?

 

[Kev555]

I will post back findings and where ive went wrong reading that live data as i see what you mean, shouldnt be a normal speed reading with ESP light on the cluster from that side.

 

[GreenMachine86]

Hi I have exactly same issue I have tried 2 speed sensors abs and esp still remain. Did you find a solution to your issue? The only thing I can think of is it is the wheel bearing it's driving me mad. MOT is due tomorrow and it will fail because of it. So annoying

Sent from my HD1913 using Tapatalk

 

[Kev555]

No I haven't yet Green machine as I haven't had it back in my garage to look at it since. I dont think theres any cure other than a wheel bearing for me ATM as I could see nothing else wrong when I inspected it. I will hopefully have it back on the lift next week to cure the issue once and for all. If you find its the wheel bearing on yours let me know for curiosity. The bearing has the magnet in the dust seal on these rather than a reluctor ring, thats why I figured the bearing replacement is the only solution. If I get it driving on live data as Alexander suggested above I will post back any findings.

 

[ajlsl600]

Ussual shixx replace a good wheel bearing cos some git organised seal, magnet comes as all. Smells like another buy tank to get sensor job t me.

 

[Kev555]

Yes especially when I can find no other fault with the wheel bearing

 

[Kev555]

Speed of solving a problem isn't my strong point but finally I got around to changing the wheel bearing on that side and it cured the ABS warning lights. I've just found that both wheel bearings are gone by the looks of it as rear right is showing the same fault code now. I did find the bearing very stiff when spinning the wheel on that side after replacing brake shoes. Woes never end as i also discovered a broken coil spring which you have to remove the plenum chamber to get at strut top bolts ******** Mercedes!