ABS Fault

Miserable Git · Jul 3, 2022

Hoping someone might be able to help. I fitted a new front tyre about a month ago as I’ve done lots of times without issue apparently. I set off for a ride a day or two later and applied the front brake on the drive and the abs went wild and then the warnings appeared on the dash. I don’t have a gs911 and probably won’t be able to use one if I had. I fitted a new rear sensor a few years ago so took a stab at a replacement front but still no joy. Steve at Rainbow Workshop plugged his gs911 in and cleared all stored faults and thought there was now nothing wrong so off I set. The abs went wild again before I got out of his yard and on came the warnings. He plugged back in and there was the front wheel sensor fault.
I’m back on trying to fix it with no luck. All three sensors that I now have test ok, I’m getting 11.9 volts to the connector for the front sensor. I’ve had the wheel out and checked the abs ring and can’t see any damage. The sensor is fitted correctly to the forks and fully flush but there is a large air gap which I presume that it’s always had.

Thanks.

DrFarkoff · Jul 3, 2022

Miserable Git said:
Hoping someone might be able to help. I fitted a new front tyre about a month ago as I’ve done lots of times without issue apparently. I set off for a ride a day or two later and applied the front brake on the drive and the abs went wild and then the warnings appeared on the dash. I don’t have a gs911 and probably won’t be able to use one if I had. I fitted a new rear sensor a few years ago so took a stab at a replacement front but still no joy. Steve at Rainbow Workshop plugged his gs911 in and cleared all stored faults and thought there was now nothing wrong so off I set. The abs went wild again before I got out of his yard and on came the warnings. He plugged back in and there was the front wheel sensor fault.
I’m back on trying to fix it with no luck. All three sensors that I now have test ok, I’m getting 11.9 volts to the connector for the front sensor. I’ve had the wheel out and checked the abs ring and can’t see any damage. The sensor is fitted correctly to the forks and fully flush but there is a large air gap which I presume that it’s always had.

Thanks.

What bike and what fault codes before he cleared them ??

I suspect that its a 1200 being in this section but Servo or the later one

How large an Air gap ??

too many variable Stop throwing bits and "thoughts" at it and get it diagnosed

Start with the GS911 and see what the code says ??

Honestly its £50 better spent than running around "trying" to fix it !

Miserable Git · Jul 3, 2022

Sorry about That DrFarkoff. It’s a 2012 1200GSA and the air gap is around 2.5mm, a full pack of feeler gauges will fit. It’s never been plugged in since about 2,700 miles and it’s now on 77,000.

DrFarkoff · Jul 3, 2022

Miserable Git said:
It’s a 2012 1200GSA and the air gap is around 2.5mm, a full pack of feeler gauges will fit.

Hmm that does seem excessive It used to be only Sensor gap:...... 0.45...0.55 mm (0.018 ... 0.022 inch) [Admittedly 1150 type But if the Sensor is too far away from the tone ring it won't develop the pulses and "See" the front wheel turning

The clue is that the fault cleared but came back after you rode off a bit?? I suspect it is to do with the wheel position ? :rob

But the fault code should read something about zero signal or implausible signal

Is your pulse ring dirty or rusty ?

Have you definitely centred the axle correctly ?

Miserable Git · Jul 3, 2022

The pulsing ring looks fine to me. I’ve had the wheel out several times and you can’t really fit it incorrectly. The axle has screwed in with the spacer and I’ve torqued it up. The callipers fit perfectly.

Skudd · Jul 3, 2022

I'd say that you have chaffed the cable ( I did that on the rear) Try a new sensor and make sure everything is clipped in correctly along the cable route.

Miserable Git · Jul 3, 2022

Fitted a new front one and no change. Put the old front on the rear and no change an today put the the old rear on the front and still no change. None of the faults were current when he plugged the gs911 in but it didn’t work. It’s been like this about 4 weeks and I’ve just ridden it as is. A couple of times the warnings have disappeared when the engine is started but as soon as the front brake is used the abs goes mad and then the warning light back on.

Caerelon9176 · Jul 4, 2022

I had a similar problem with my speedo bouncing, GS911 showed it as the rear speed sensor, replaced it and all was fine. When I went to BMW for the hub replacement I think they got the heat gun out and melted the sensor, had to drill the bugger out in the end.

Sounds like you Knocked/Damaged the front, the routing of the front cable does cause issues if too tight, especially where you turn and it is all fouled up. Check it, if ok and you have replaced the sensor then...remove the power to the ECU by disconnecting the battery and reconnecting it after 10-15 secs. When the bike starts it goes thru its self-check, the ABS doesn't expect a signal till after you get moving then try riding off. Sounds like it is a logic issue with the ABS pump, reset it by removing the power.

There is a ring spacer that goes on the front sensor, I take it was replaced?

Miserable Git · Sep 28, 2022

So, I’ve now purchased a GS 911 from a kind chap of this parish and I’ve been playing with it this evening. Since I posted the first time I’ve covered 4 or 5 thousand miles without abs or traction control Ignoring the warning as if it wasn’t fitted. Tonight I cleared the stored faults That were the same as the ones in post 3 and tried the brakes. Previously When I tried this the front brake lever was stiff and pulsing and the warning light came on and the brakes defaulted to the no abs fitted feel but tonight I get the same feeling on the lever but no warning lights and it’s now dangerous to ride. Any ideas from the knowledgeable would be great.
Thanks.

knutk · Sep 28, 2022

Miserable Git said:
So, I’ve now purchased a GS 911 from a kind chap of this parish and I’ve been playing with it this evening. Since I posted the first time I’ve covered 4 or 5 thousand miles without abs or traction control Ignoring the warning as if it wasn’t fitted. Tonight I cleared the stored faults That were the same as the ones in post 3 and tried the brakes. Previously When I tried this the front brake lever was stiff and pulsing and the warning light came on and the brakes defaulted to the no abs fitted feel but tonight I get the same feeling on the lever but no warning lights and it’s now dangerous to ride. Any ideas from the knowledgeable would be great.
Thanks.

Does this mean that the Undervoltage warning is also included at every reading?

If so, this may point towards a battery that is not pulling it's weight under load, and this may influence the ABS function.

Both sensors failing simultaniously is not very common....

botus · Sep 29, 2022

Miserable Git said:
tonight I get the same feeling on the lever but no warning lights and it’s now dangerous to ride. Any ideas from the knowledgeable would be great.
Thanks.

I've had the std ABS11 module failure 3 times on BMs, twice on my GS

the first time it failed in some sick dangerous condition no one here believed - it felt normal on both lever and pedal, but the front would lock up under almost any gentle braking condition - I had planned to leave it and get round to the fix in the winter - it was so deadly I took the module off that night and sent off for repair

the second time it failed leaving the brakes operating normally, with just no ABS

funny enough had a car where the ABS failed and that too would go mad and randomly lock individual wheels whilst the driver was braking normally

Miserable Git · Sep 29, 2022

botus said:
I've had the std ABS11 module failure 3 times on BMs, twice on my GS

the first time it failed in some sick dangerous condition no one here believed - it felt normal on both lever and pedal, but the front would lock up under almost any gentle braking condition - I had planned to leave it and get round to the fix in the winter - it was so deadly I took the module off that night and sent off for repair

the second time it failed leaving the brakes operating normally, with just no ABS

funny enough had a car where the ABS failed and that too would go mad and randomly lock individual wheels whilst the driver was braking normally

I’m starting to think this might be the issue. Going to have a look over the weekend.

Miserable Git · Sep 29, 2022

knutk said:
Does this mean that the Undervoltage warning is also included at every reading?

If so, this may point towards a battery that is not pulling it's weight under load, and this may influence the ABS function.

Both sensors failing simultaniously is not very common....

The battery is new and cranks well. I think the read out is because the engine wasn’t running.

botus · Sep 30, 2022

the normal pump motor brush fault always comes up when its wrong - same / very similar module in most cars and bikes - don't know why he's wasting time talking about it nearly always the brushes gummed up - but all your error codes I've never seen

I did post ages back when the rear sensor snaps its wires (as they designed it - over doing the routing of the wires so movement of the suspension stresses the same bit till it fails) it throws the front sensor error. The ABS expects random gibberish from the sensors as that's related to grip levels out there, but the early traction control ASC tries to work from seeing both wheels always turning at the same rate - so if rotation is different due to a failing sensor it doesn't necessarily know which is wrong, so just picks the first in the list and says fault

https://www.youtube.com/watch?v=-P6OhJjgI6w

https://www.youtube.com/watch?v=V4LkqdD-26o

https://www.bmw-motorrad.co.uk/en/engineering/detail/Safety/asc.html

Miserable Git · Oct 1, 2022

I’ve found the reading from the front sensor is all over the place so I put the dial gauge on the exciter ring and found it is slightly bent which must be the problem I think. Will find out in a few days when the replacement arrives. The discs need changing so will kill two birds with one stone if I can get the bolts out.

Miserable Git · Oct 1, 2022

botus said:
the normal pump motor brush fault always comes up when its wrong - same / very similar module in most cars and bikes - don't know why he's wasting time talking about it nearly always the brushes gummed up - but all your error codes I've never seen

I did post ages back when the rear sensor snaps its wires (as they designed it - over doing the routing of the wires so movement of the suspension stresses the same bit till it fails) it throws the front sensor error. The ABS expects random gibberish from the sensors as that's related to grip levels out there, but the early traction control ASC tries to work from seeing both wheels always turning at the same rate - so if rotation is different due to a failing sensor it doesn't necessarily know which is wrong, so just picks the first in the list and says fault

https://www.youtube.com/watch?v=-P6OhJjgI6w

https://www.youtube.com/watch?v=V4LkqdD-26o

https://www.bmw-motorrad.co.uk/en/engineering/detail/Safety/asc.html

Thanks for your help Botus.

DrFarkoff · Oct 1, 2022

Miserable Git said:
if I can get the bolts out.

Make sure and heat the bolts well! They have a "Micro encapsulated" thread lock on them

Fancy words for that pink spongy looking stuff on the threads But its bloody effective! and You could damage the internal threads (and the wheels)

Also blow out the bolt holes for any pink dust and if the bolt is tight going in with a couple of drops of new thread lock

Run a tap down to clear the shit out of the threads it Its a Messy set up almost one time use only!

botus · Oct 1, 2022

the discs in the photo look almost like new - a tiny bit of wear were some dirt or cheap pads have made a few marks, but can't see any substantial wear ridges in the those pics

and the reluctor ring is just mild steel made of no strength, bend it straight with your fingers?

Miserable Git · Oct 1, 2022

DrFarkoff said:
Make sure and heat the bolts well! They have a "Micro encapsulated" thread lock on them

Fancy words for that pink spongy looking stuff on the threads But its bloody effective! and You could damage the internal threads (and the wheels)

Also blow out the bolt holes for any pink dust and if the bolt is tight going in with a couple of drops of new thread lock

Run a tap down to clear the shit out of the threads it Its a Messy set up almost one time use only!

Thanks DrFarkoff.

Miserable Git · Oct 1, 2022

botus said:
the discs in the photo look almost like new - a tiny bit of wear were some dirt or cheap pads have made a few marks, but can't see any substantial wear ridges in the those pics

and the reluctor ring is just mild steel made of no strength, bend it straight with your fingers?

They are about on the limit and I have a new pair on the shelf that I acquired at a good price so I may as well fit them.

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