Motorcycle Classics Blogs > Tech Corner

Tech Corner

Technical Q and A for classic motorcycle maintenance and repair.


BMW K1200RS ABS Lights

Motorcycle Classics tech expert Keith Fellenstein

Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.

ABS lights

Q: I have just bought a BMW K1200RS, but I’m having a problem with the ABS lights. There are two ABS lights on the dash, and they keep flashing. I have tried to clean the sensors on the front and back wheel, but the lights keep flashing. Do you have any suggestions that I might try?  Allan/via email

A: When you start your BMW, the ABS computer initializes itself and does some internal testing. It can’t complete the final test until you move the bike. That test involves counting pulses from the sensors attached to each wheel that check to see that the wheel is still rotating when you apply the brakes. If there is no problem with the ABS system, the flashing lights should go out the first time you apply both front and rear brakes. If the warning lights stay on after that, there is a more serious problem and you’ll have to take the bike to a BMW shop that has the proper diagnostic equipment. To my knowledge, nobody has created any sort of diagnostic shortcut for the ABS on these bikes.

tonyc
2/25/2016 12:28:24 PM

It's a bit more complicated than that. The K1200RS used two different ABS systems during its model run. 1999 thru 2001 used what is basically the same system used on previous K1100s; AKA ABSII. Model years 2002 thru 2004 used a completely different system which combined the ABS with an electric boost pump. That system is known either as e-brake, or that #%@^! braking system. Flashing ABS lights on an ABSII system do indicate that the system was unable to initialize itself during the first movement of the bike after start-up. Most common cause of that is an undercharged battery. The quick test (short of a new battery) is to ride the bike for half an hour, with lights flashing, then shut it down. The battery should be fully charged at that point. Restart the bike and ride off. If the lights go out it's a sign the battery was weak. Diagnosing the e-brake system is vastly more complicated, and too complex for this medium. But my experience points me to some common problems. Often a novice will attempt to bleed the e-brakes, using the common techniques used on virtually every other brake system in the world (did you hear that, BMW?) Big mistake. If you try sucking at the nipple, or pumping from the master, you only drain half of that circuit, and it's not the most visible half. The result being you've drained one of the reservoirs, but not the one you were expecting to be topping up. At that point most novices give up the job. Problem is the system sees the empty reservoir that the bleeder did not, and trips the warning lights. Best answer is get it to someone who knows what he's doing.