So after several weeks of troubleshooting an ABS problem with my 1200GS I thought I'd post a summary of the issues and the final solution here in case it can help anyone else.

Background:
I've got just under 70,000kms on the bike
2007 Model BMW 1200GS
ABS version II
We have ridden all terrain, not just road.
I use the GS-911 diagnostic unit connected to my WM5 HP iPaq phone.
The ABS issue occured just after another error with the wheel speed sensor (41445 I think).

Error reported by GS-911:
10220: Can-bus timeout: no communication with ABS control unit.

Symptoms:
Brake Failure warning light on the Dashboard.
ABS doesn't work.
No speedo.
No odometer (ie. no distance travelled is recorded at all, counter stays at zero)

Inspections and repairs:
There are no issues with FD (yet) checked play on rear bearings.
There are no metal shards or filings in the FD oil.
The battery was dead so I have replaced the battery.
I have inspected both front and rear wheel speed sensors. The rear looked damaged by heat and so I replaced it.
The bike runs fine apart from the Brake Failure warning light.
The Dash works fine, ie clock, fuel indicator revs and oil temp all work fine.

The brake fluid was changed (supposedly) last year (under 20,000kms). BMW recommends every 2 years of 20,000kms. So I can't see why this should be a problem.

As a result of the constant brake failure, my rear brake light didn't work when activated by either front or rear brakes. IMO This is very dangerous. All the other problems linked to the ABS failure are ok and means the bike is ridable but no brake lights are for me a critical saftey issue.

I had run out of options so started calling BMW mechanics to get their input, I finally resorted to taking it into a BMW repair shop and they diagnosed using the BMW diagnostic unit. I didn't get the exact read out but it was something along the line that the ABS pump failed and could not be re-initialised. The mechanic I told me he tried to reset/flash the ABS unit but this didn't help.

The Mechanic didn't try to bleed the circuit but I think it probably was too late if the ABS had already completely failed...

Bottom line:
ABS is toast. I need a new ABS pump. This part is $1700.

The Mechanic is also doing a couple of recalls on my bike at the same time. I'll let you know the pain when I get the bike back, but it's likely to be over $2000...

__________________
TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

Not that this will help, but the diagnostic process and error code descriptions make perfect sense, which isn't always the case.

Who changed the brake fluid? If a dealer was involved, introduce the idea that they may have powered the system up with the ABS unit dry. The brake fluid lubes the ABS unit, so if they had run it dry some sort of contribution might be in order.

No ones done any welding or jump starting have they? Ten years of handling warranty claims on ABS bits and these two pop up time and time again as the single most effective way to cause this sort of issue.

Andy

Hi Andy,

Thanks for the reply. Unfortunately I already asked BMW to contribute and they said no. I don't really have a leg to stand on although I'm very peeved about the ABS failure. Basically I think that the ABS fluid when changed was over a year ago and the dealer is no longer handling BMW anymore so not going to help my cause.

Oh and no welding or any jump starting has been done on the bike. Although now that you mention it, I did short the battery to the frame when I was swapping out the old battery, there was a spark. Do you think that is could have triggered the ABS unit to fail?? I would be very surprised and would like to know more if you think it could be the cause...

Cheers
Pascal

__________________
TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

Pascal

I have a 2007 1200GS which has just completed a RTW with no problems so your problem is of interest to me. A rather stupid question possibly....... but if you turn off the ABS do the brake lights work then bearing in mind you have overridden the pat of the bike causing the problem ?

Martin

Hi Martin,

The ABS failure caused the ABS to be off all the time so it was not possible to toggle the ABS (with the ABS button on the handlebar) during the failure.

On a bike with working ABS if you toggle the ABS off then the brake lights will work. They should always work, but check this, if not then you have a problem.

The problem with my bike and the ABS failure is that the error code (10220 when interrogated with GS-911 diagnostic tool) said that the CANbus didn't communicate to the ABS unit, it just timed out. The CANbus interpreted this as a brake failure so failed to interpret the brake switch activation on front and rear of the bike. Again all this was related the the ABS failure.

End result of all this complex ABS integration meant:

• no odometer
• no speedo
• no brake light
• and of course no ABS

IMHO this is a poor and very dangerous design, to have speedo and especially brake light dependent on the ABS unit.

Cheers,
Pascal

__________________
TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

On a final note, and as I've seen recommended on other forums and was recommended by multiple BMW mechanics, the ABS needs regular
maintenance. It also needs to be used. Some suggest applying ABS on a
semi-regular basis (ie. going downhill on loose surface or on wet grass) to ensure the ABS unit is exercised. Also I have been recommended to change and bleed the entire brake fluid at least every 2 years or 20,000kms as a minimum. I will do this more often now as it is a lot cheaper than a new ABS!!!

__________________
TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

IMHO the odd spark/short shouldn't do any harm, but if you combine it with a bad bit of soldering on the production line or the last percentile component in the quality range it might be enough to send it over the edge.

The "exercise your ABS" plan is utter guff. The ABS does a full self test valve cycle at each ignition on (the clunk click as the lights change sequence on the older systems, more subtle on later ones) and partially energises the solenoids every few seconds to confirm they are electrically OK. Deliberately cycling the ABS on wet grass (a surface it is not designed for) is only good for sales of new body panels, levers, mirrors and medical insurance.

Changing the brake fluid as required is a good plan to get water out. Don't do it too often and leave the ignition off until you have a fully bled and working hydraulic set up, the fluid lubes the pump and valves.

The routing of the brake lights via the ABS ECU is highly suspect IMHO. The whole point of CAN is to utilise the info you have over the whole network, so telling the ABS to "wake up" via the brake light change of state is a good use that will improve its reactions. The fact is though that this signal can be picked up via the general network, the ABS can be a "listener" without having any direct input. Strikes me that the boys in Munich ran out of capacity on the instrument module and rather than expanding it decided to put the brake light reaction into the ABS ECU. Running the actual brake light wires a whopping 1 meter less saved them something too. I understand such logic on a bendy bus or a truck with potential road train uses, but on a 2m long bike it's ridiculous corner cutting.

Andy

Mmm, not convinced but you are quite possibly right even if I want to deny it.

Agree with your sentiment and the technical aspect makes sense but what would you say about old brake fluid becoming (more) corrosive and detroying ABS filters?

So do you think that brake fluid goes bad (ie corrosive and detroying seals or filters) or not? Could this be the cause of the ABS failure?

I pulled up stumps on this one. No idea what would posses them to have such a dependency - makes no sense at all to me.

__________________
TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

Brake fluid is hydroscopic, it absorbes water. This is bad for two reasons; first of all if you heat it by getting close to the rubbing surface and change pressure with the brake cylinders it turn to steam which is compressible and therefore allows the pads to drop back. The brake feels spongy. Secondly, if left to settle out the water will accumulate at surfaces such as o-ring grooves. As these are made of alloy and often have air on the other side they rot and fur up blocking the small passageways. There are no filters on any hydraulic ABS system I ever worked on although my work with BMW was very short and limited to 4x4's.

I can't remember the numbers, but the absorbtion of water constantly increases through the fluids life. At two years the change is measurable on the standard tests, hence thats when the manufacturers want to sell you more. At five years you'll see furry valves and no doubt feel the effects. Between the two is between the two and will of course vary with how the vehicle is used, where it is etc. I buy the brake fluid at two years and it gets changed at the next engine oil service or before the next trip.

Andy

Got the bike back today and I'm happy to say all my problems have gone away!!

Thanks to the team at Motos Vionnet.

(No I'm not paid for the plug and I didn't even get a discount )

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TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

Any insights about the final diagnosis of the ABS pump? Did it fail due to fair wear and tear/old age (2007 bike) or is there any better insight?
Just being curious about your useful, but expensive, experience.

Thanks to 3Wbonnie for clearing up some technical issues, including the lack of filters in ABS systems (I was wondering about that!).

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Dave

Glad you are up and running.

Andy

Unfortunately the short answer is no. The mechanic may not be experienced enough or perhaps it's more the fault of BMW that makes the ABS unit a non-servicable part.

The bottom line here is ensure your brake fluid must be changed every 2 years and the full brake circuit is bled.

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TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

The ABS unit is assembled in close to clean room conditions and contains many small parts, a lot of them press fit. The hydraulic units I'm most familiar with (Landrover) were supplied as only two part numbers; complete ABS unit wet and complete ABS unit dry. The only difference was that the wet one was easier to bleed (all the nooks and crannies filled with fluid) and the dry one could be sent air freight. Dealer service techs were not expected to do anything except change the whole unit. It isn't any lack of skill on the part of a lot of techies, it's how the things are designed with input from the lawyers and parts department accountants.

Andy

Thanks for the heads up Pascal - I am pleased that you are up and running and now I think it may be time to change my brake fluid !

Also Thanks to ThreewheeledBonnie for your input.

Martin