ABS red warning light coming on intermittently

[Marvin2Shoes]

Just on a 1200km ride over two days. I have had the ABS light come on three times today (never happened before today)
When it comes on the cruise control drops out... Very annoying! If I stop the bike and restart it then it runs again no problem for an hour or two. After it comes on I can't detect any problems with the bike, brakes operate perfectly, just the cruise won't set. Has anyone had this problem?

[Stu]

First port of call would be to get the error codes read

I suspect maybe an ABS sensor is playing up

[David.]

I agree with Stu (sakm), although I haven't had this problem myself on a Camhead, found this thread on BMWLT which may be of interest.

https://www.bmwlt.com/threads/r1200rt-a ... ure.37756/

Check the F&R ABS sensors are clean and cables not damaged.

[Marvin2Shoes]

I rode 5 hours straight on the second day and not an ABS error to be seen. The ambient air temperature was lower for the second days ride, maybe this had an affect...?!
I also rode through some mud on a road near Ayr left by the cane haulers which are carrying sugar cane to the mill.
Perhaps some mud flicked up. I will give everything a good clean and check cabling route and integrity.
Many thanks for your replies.

[Marvin2Shoes]

A short 150km ride later and the dreaded warning appeared about 120km into the trip. No apparent reason. I have since removed both front and rear sensors and cleaned and inspected the ABS cabling until it moves beyond the moving parts. There are no detectable anomalies. After reading many forum comments on many R1200 websites and thoroughly reading the Haynes manual I have concluded that the ABS system is not intended to be repaired by the owner. When it dies it will be getting bypassed and it will be tossed in the bin. This is the first bike I have ever owned that had ABS and after 44000kms travelled in total it is the single largest cause of apprehension on my rides. Who needs a safety feature that causes such stress?
Re the forums: to the BMW owners who suggest ppl should do away with applying the rear brake pedal... I can see them riding a large, non-ABS, non-joined-front-rear-brakes motorcycle in the rain at some point in the future. This reminds me why the Darwin Award exists.

[Marvin2Shoes]

Ok, have hooked up Motoscan and checked ABS errors. It says "Low Voltage" and "Rear sensor" so I guess the first step is to replace the lead acid battery with a lithium battery as putting up with losing my cruise control every three years seems a ridiculous proposition. Has anyone had any luck finding a retailer of lithium compatible regulator/rectifiers that are for 2011 model.... Lithium reg/rect for 2013 onward is easily found.

[David.]

The first step is to replace the lead acid battery with a lithium battery as putting up with losing my cruise control every three years seems a ridiculous proposition.

Which battery is currently fitted to the bike.

[Marvin2Shoes]

A yellow 6.7kg Motobatt MB51814 AGM battery is currently being used. This is a heavy battery compared to Lithium... Literally three times as heavy as a similar sized lithium battery I have here and almost ten times heavier than the lightweight lithium models.
There is a worrying side to this... I don't know the age of this battery and it is completely possible that the previous owner had already attempted to fix the problem by fitting this battery. It may be something like an intermittent wiring connection causing this error. What I do now know is that the motorcycle dealer I purchased the bike from has on-sold the bike with this intermittent ABS fault, possibly unknowingly. I can be pretty sure the previous owner knew very well what it was they were selling. Unfortunately I am now stuck with fixing the fault, after which I am pretty certain I will on-sell it. This whole mess has left a bad taste in my mouth with respect to BMW motorcycles. The mechanical wonder is being seriously let down by very sub-standard electronic support systems.

[David.]

I don't know the age of this battery and it is completely possible that the previous owner had already attempted to fix the problem by fitting this battery.

Can the battery be bench tested or some voltage checks be done with it on the bike.

[Stu]

Does the fault code clear and if so at what point does it come back on?

Low voltage can be a sign of a battery on its way out and its at the point of starting the bike when the low voltage occurs

[Marvin2Shoes]

And therein lies the problem I have with the battery. This fault has never manifested within the first 20 minutes of riding, even on cold mornings further south. This leads me to think that the battery is still fine. I reset the error.... Now to wait for it to come back.

[Marvin2Shoes]

Well it has started throwing up the error when I first start off. Interesting to note that when the ABS fault occurs, the brake light stays lit until the bike ignition is turned off.
If you see this error on your dash please make sure you don't have any vehicle behind you as you slow down to pull off the road. A truly odd safety feature if ever there was one.
The latest output of Motoscan app can be seen in the attached screenshot....

[David.]

Interesting to note that when the ABS fault occurs, the brake light stays lit until the bike ignition is turned off.

The brake light switches are integral with the ABS control unit. Could this now be pointing towards a problem with the ABS unit itself.
AFAIK, with the ignition on, the ABS pump is running.

[Stu]

Are the brake light switches replaceable?

It could be a sticking brake light switch

[David.]

Are the brake light switches replaceable.

See if you can make any sense of this from Adventure Rider, https://www.advrider.com/f/threads/bmw- ... s.1443073/