R230 - Speed Sensor

kevh

Senior Member
Joined
Dec 27, 2015
Messages
60
Reaction score
4
Location
Sheffield
Your Mercedes
SL500 (R230) 2003 4966cc
SL500 2003 - A recent STAR report has flagged up a potential problem with my 'left rear speed sensor'. The car's electronics are apparently not getting a plausible speed signal from this sensor.

I have warning lamps for ESP and ABS displaying all the time.

The dealer's service technician tells me that this should all be corrected if I replace the speed sensor.

Can anyone please comment? If this is likely to correct my issues, how easy is it to replace the speed sensor?
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,326
Reaction score
21,574
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Yep you have a bad ABS sensor. It will give all those symptoms (and often more).
Usually fairly easy to change but first check the reluctor ring for rust and corrosion or damage. Often simply cleaning the reluctor ring will fix issues if they are badly corroded.
 
OP
K

kevh

Senior Member
Joined
Dec 27, 2015
Messages
60
Reaction score
4
Location
Sheffield
Your Mercedes
SL500 (R230) 2003 4966cc
  • Thread Starter
  • Thread starter
  • #3
Hi Lost Kiwi,

Thanks for your reply. Could you please explain what the reluctor ring is.

Regards
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,326
Reaction score
21,574
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
^^^this ^^^
Its the toothed casting on the driveshaft or hub that generates the signal in conjunction with the ABS sensor.
 

Steve@Avantgarde

Forum Supporter
Authorised Forum Supporter
Joined
Dec 8, 2009
Messages
7,314
Reaction score
1,955
Location
Bristol/Somerset
Website
www.avantgarde-automotive.co.uk
Your Mercedes
E300 Coupe AMG Line PP/NE, SLR McLaren Roadster, SL55 & C32AMG
Usually the reluctor rings can corrode away..which will cause a sensor issue. The only way to check is to remove the sensor and inspect through the hole.
 

Submariner1

Senior Member
Joined
Sep 3, 2016
Messages
4,689
Reaction score
787
Location
Windsor Berkshire
Your Mercedes
CL500 2009 5.5
^^^this ^^^
Its the toothed casting on the driveshaft or hub that generates the signal in conjunction with the ABS sensor.

Thanks for the explanation ... I kno pw what the reluctor ring is, and what it looks like; and the requirement to clean them if the signal fails and the actual bolt on sensor plug thingy is OK.
I was however interested to know how a toothed/cogged wheel generates that "signal" is it some sort of magnetic or inductive thing?

I also read that too much Coppa Slip can effect them, but not personally ever had an issue with it. But then I do use that MB grey paste ( no idea what is in that either, maybe it has aluminium particles rather than copper )
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,326
Reaction score
21,574
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Thanks for the explanation ... I kno pw what the reluctor ring is, and what it looks like; and the requirement to clean them if the signal fails and the actual bolt on sensor plug thingy is OK.
I was however interested to know how a toothed/cogged wheel generates that "signal" is it some sort of magnetic or inductive thing?

I also read that too much Coppa Slip can effect them, but not personally ever had an issue with it. But then I do use that MB grey paste ( no idea what is in that either, maybe it has aluminium particles rather than copper )

Within the sensor is a coil wrapped around a magnetic core. The movement of the toothed ring induces a voltage within the coil proportional to the vehicle speed.
 

Submariner1

Senior Member
Joined
Sep 3, 2016
Messages
4,689
Reaction score
787
Location
Windsor Berkshire
Your Mercedes
CL500 2009 5.5
Within the sensor is a coil wrapped around a magnetic core. The movement of the toothed ring induces a voltage within the coil proportional to the vehicle speed.

Thanks so a bit like a brushless induction motor in reverse .
 
OP
K

kevh

Senior Member
Joined
Dec 27, 2015
Messages
60
Reaction score
4
Location
Sheffield
Your Mercedes
SL500 (R230) 2003 4966cc
  • Thread Starter
  • Thread starter
  • #10
Thanks for all the info guys.

Despite lots of penetrating oil and being very careful with the removal of the speed sensor, the sensor itself has sheared off the backplate and is stlll in the hole. I clearly need to remove this. Can it simply be drilled out? Can debris be allowed to drop into the hub reluctor ring housing? If this is going to be an issue. How do I get to the reluctor ring so I can protect it prior to drilling?
 

LostKiwi

Senior Member
Joined
Aug 25, 2006
Messages
31,326
Reaction score
21,574
Location
Midlands / Charente-Maritime
Your Mercedes
'93 500SL-32, '01 W210 Estate E240 (RIP), 02 R230 SL500, 04 Smart Roadster Coupe, 11 R350CDi
Thanks for all the info guys.

Despite lots of penetrating oil and being very careful with the removal of the speed sensor, the sensor itself has sheared off the backplate and is stlll in the hole. I clearly need to remove this. Can it simply be drilled out? Can debris be allowed to drop into the hub reluctor ring housing? If this is going to be an issue. How do I get to the reluctor ring so I can protect it prior to drilling?
Yes just drill it out - the casing is just plastic so should be easy. No real need to take any massive precautions to stop bits getting into the reluctors as they are open to the elements anyway.
 

Submariner1

Senior Member
Joined
Sep 3, 2016
Messages
4,689
Reaction score
787
Location
Windsor Berkshire
Your Mercedes
CL500 2009 5.5
Thanks for all the info guys.

Despite lots of penetrating oil and being very careful with the removal of the speed sensor, the sensor itself has sheared off the backplate and is stlll in the hole. I clearly need to remove this. Can it simply be drilled out? Can debris be allowed to drop into the hub reluctor ring housing? If this is going to be an issue. How do I get to the reluctor ring so I can protect it prior to drilling?

Very sorry for you.
Both mine ( that I tried ) moved very easily after just squinting some engine oil at the joint ... I had run out of penetrating oil ... as soon as I undid the bracket bolt they moved using two fingers.

Having looked in the resultant hole, once they are removed.... one can see the cogged teeth.

Personally I would be very reluctant to drill that:-
1. Swarf may mess up the signal
2. To clean swarf out properly, on mine would mean taking out the driveshaft?? :(:(
3. Not sure if you enlarged the hole accidentally what would that do to the data?

The part my sensor goes into looks VERY expensive.

I would definitely take it to a very experienced Indy, pref one who had dealt with this issue.

They may have some sort of screw extractor to screw into the remnants of the sensor and then pull it out.

Sounds a real pig, on mine access isnt exactly easy

Note I don't have your car, but have owned 230s from 2003-2005 build and they look fairly similar to this CL500.

JUST SEEN LKs POST .... GO WITH HIS ADVICE HE KNOWS A LOT MORE THAN ME.
 

star

Forum Supporter
Authorised Forum Supporter
Joined
Oct 6, 2004
Messages
6,209
Reaction score
1,874
Location
Reading
Your Mercedes
Smart + others :)
Be very careful drilling out, you may have a rubberised reluctor ring, which will be destroyed if the drill touches it.
 
OP
K

kevh

Senior Member
Joined
Dec 27, 2015
Messages
60
Reaction score
4
Location
Sheffield
Your Mercedes
SL500 (R230) 2003 4966cc
  • Thread Starter
  • Thread starter
  • #14
Thanks for your advice everyone. Once I've purchased a new sensor I can measure the probe, so that I don't drill too far and then I'll insert a stud removal tool or the square end of a file into the hole, so I can carefully coax it out.
 
Top Bottom