SPEEDO NOT WORKING ! Need HELP

SPIDER99

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Hi folks, my speedo has stopped working on my 2004 r1200gs and I have done the usual checks on the wiring,and the speedo needle moves when the ignition is switched on ,so I presume it has power .
Plugged in gs911 and fault code 25072 rear sensor ADC value incorrect , so have fitted a replacement and guess what still no speedo, plugged in 911 again and this time no fault on rear sensor , checked the input signals of front and rear sensors and the front is showing 1.44 volts and the rear is showing 0.08v , any one know what voltage reading they should have ?
Or any thoughts on what it could be , as running out of ideas :mad:
 
Does it use the ABS sensors to drive the speedo? Is the odometer working ?
Think I'd disconnect the battery & reconnect before doing more diagnostics.


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Speedo

Does it use the ABS sensors to drive the speedo? Is the odometer working ?
Think I'd disconnect the battery & reconnect before doing more diagnostics.


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Yup it uses the abs sensors , from the rear wheel for the speedo , battery has been disconnected over night , but still not working Thanks for the ideas
 
Disconnect the rear sensor and go for a ride,

the system should switch to the front sensor. if it does, its a duff rear sensor factor £60 odd for a sh replacement
 
Check the wiring to the rear abs sensor.
 
Sensor is brand new fitted yesterday, went for a quick ride round front never kicked in ? All the warning lights on the abs flashing as exspected,speedo still not working
 
That rear sensor voltage sounds low even though I don’t know what it should actually be. Have you got a corroded connection somewhere?
 
Sensor is brand new fitted yesterday, went for a quick ride round front never kicked in ? All the warning lights on the abs flashing as exspected,speedo still not working

Flashing as :-

Warnings given and extiguish

or

Warnings given and stay on?

if the former - I'd agree with Matt

if the latter - Could be ABS pump unit ( all the sparkery bits for wheel sensors run from there )
 
Thanks for all your thoughts but after spending the day on it I think that I have come across the fault.
Took the petrol tank off to see the wiring better and all looked ok , but on closer inspection after uncoupling the ecu and the plastic holder where the loom bends round near the alternator on its way to the abs ecu , the loom had been rubbing on the small terminal of the alternator and damaged a couple of wires not right through but the rear abs wire was hung on by a couple of strands , had to give up then but hopefully fingers crossed I will soon have my speedo back , thanks people for your thoughts as they say two heads better than one.
 
I've had wires chafed in the plastic trough alongside the battery. My speedo is acting up and only recently had a new (used) sensor so will have to take a look around the alternator area.

TBH you could not make this up. Car ABS systems are amazingly reliable yet these bikes play up time and again. It's not like BMW don't make cars.
 
Yup, very VERY annoying , hope you have some luck with the wiring and get it sorted .
 
Just for info , carried out input test again and voltage now at 1.25v up from 0.08v so the damaged wire could not carry the current down the two strands of wire left undamaged so the signals from the rear sender unit were too weak, hope this helps someone in the same situation.
 
Just for info , carried out input test again and voltage now at 1.25v up from 0.08v so the damaged wire could not carry the current down the two strands of wire left undamaged so the signals from the rear sender unit were too weak, hope this helps someone in the same situation.

Well done on diagnosing the fault and making it known on here. Another one in the bank :thumb2
 
Absolutely. I checked out my "cram it with wires and hope" side frame loom tray and all seem ok). Here's another place to look.
 
So where's the best place to buy a rear wheel sensor as mine is now acting up?
 
So where's the best place to buy a rear wheel sensor as mine is now acting up?
Can you give more info on what you mean by "acting up"?

But in short, just but BMW OEM for this kind of thing

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En route to a MOT no speedo and "brake failure" flashing.
After about 4 miles (5 mins.) warning goes solid and speedo works!

After MOT (passed) solid warning and no speedo but, after about the same distance as earlier, speedo starts to work with solid warning still shown.

I'm still guessing it's a rear wheel sensor.

What a pain as I've just put the rear wheel back on!

Good news: two BMWs got MOTs.

Next Thursday it's the two Ducatis turn.
 
You might get away with removing the sensor and cleaning it.
Take care with the O ring.
My 1200 went through, I think it was 4 sensors in the ten years I had it, so there’s definitely a design problem there.
 


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