Speed Sensors Gone Again

[Kevin]

I was out on a run yesterday when my Speed Sensor went again.
This will be my 3rd Sensor to replace. I am hoping someone might be able to tell me what the problem is, why do the sensors keep going. Anyone know why this might be happening etc. It is an R1200GS 2004

Kevin

 

[fizzer]

just bad luck i think,nothing that i am aware that can cause it as such.did you fit new or second hand.

 

[Pukmeister]

By 'speed sensor' do you mean the rear wheel speed sensor inside the final drive ??

Have you removed it yourself and inspected/cleaned it if covered in fine metal particles??

They stop working when they get covered in metal particles and can no longer create a square waveform signal through the inductive effect of the crownwheel segments moving through the lines of flux. A clean usually sorts this, including any ServoABS faults that can also occur because of it. Repeated build up of particles points to wear in the final drive somewhere, probably the needle roller track of the input pinion bearing.

If you are referring to some other 'speed sensor' then please ignore the above.

 

[Kevin]

No I have not yet removed it, I will do shortly and I will see if there is any build on the sensor. I will look and see if there is any rubbing or shafing from the ABS. Thanks for the replies.

Kevin

 

[Kevin]

Another Brand New Speed Sensor Failure

Bought another speed sensor and put it on the bike R1200GS 04.
Went out this morning and nothing happened, still getting Brake Fail light flashing while the speedo still just sits there and bounces every now and again. Looks like I will have to book in to Joe Duffys next week.
Anyone got any last minute suggestions as what might be the problem.

 

[Pukmeister]

If it bounces occasionally, it's either poor continuity/bad connection somewhere or a bad output from the speed sensor (unlikely if replaced several times) or an electronic fault with the instrument panel.

My money is on a bad connection somewhere between sensor and instrument.

 

[Kevin]

Hi Pukmeister
I willl check tomorrow the connections to ensure that it is a good connection.
Am I stating the obvious by saying the connection under the tool tray is what we are talking about or is there some other connection I should look at.

 

[Deleted account 190920001]

It wont be the instrument panel if your getting an ABS fault. The sensor goes to the main ECU which then send it out the the instruments and ABS.
I second a bad connection or damaged cable, check the cable from where you have already been to the ECU as well and the ECU connection although that is more unlikely.

 

[Spout]

I have heard that changing older rear drive for a newer one (drain hole underside and/or breather included) also needs a new sensor pick up as it's different design.
Are you sure the sensor you bought matches the rear drive? (If this is the case??)

 

[Kevin]

Hi Spout
The BMW parts dept took all the details, and provided me with a rear wheel sensor for the year of my bike, the rear drive is the original one also.

 

[Mad Mac]

For peace of mind, check the play in the final drive.
A friend with K1200s on our tour this year had a speedo failure. Turned out that the rear bearing where knackered causing the gap between sensor and ABS ring to be increased. We oly found out that was the issue on return to England when it was discovered that the final drive bearings had deteriorated and caused the bevel drive to lose a tooth......very lucky the tooth didn't cause an accident.......
It's probably not the case but for gods sake check!