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ABS fluid change went awry


New member
Changed the brake fluid on my 2003 R1150RS and all seemed to go well. This is the second time I and my trusty shop assistant have done this. Afterwards I took the bike for a test ride and the alternating warning lights on the dash came on and would not go away. (brake and triangle/exclamation point red lights flash alternately) Shut the bike off and restarted it with no change. Brakes are nice and firm as if the ABS was still working, but how do you know?

Took the bike apart again and checked all fluid levels (handlebar reservoir, rear reservoir and the two control unit reservoirs) and none were low. No leaks anywhere. Looked at the wires to the front and rear wheel sensors and they looked fine also. We are stumped. I'm four hours from the nearest dealer. (Engle Motors) I tried calling them and was told they had to lay hands on it. We had already checked everything the shop guy suggested we check. If anyone has seen this before and/or has a good suggestion for how this might be resolved by me and my trusty shop assistant, we would be most grateful. TIA
Was the flush/bleed done using the correct procedure and tools, as in using the ABS boost pump to run fluid through the system, and the proper funnel into the reservoir to assure the reservoirs wouldn’t run dry?

Were the alternating (1hz) lights on from the start, or did they come on during the ride? And do you still hear the boost pump kick in when the brake lever is activated?

First things to check, besides the fluid levels you’ve already checked, would be the microswitches at front brake lever and rear brake pedal—especially the rear.

Even if the fault is no longer present I think the warning will persist until the fault is "cleared" with a GS911 or Motroscan App or similar.
Thanks. As I read the instructions in the Hager & Gilman script from 2004, using the abs pump is only for the caliper circuits and not the control circuits. Would you agree?
I'll look at the microswitches.
The alternating flashing lights begin right after the start-up sequence, before I even get the bike out of the garage.
On my three oilheads, the warning lights would extinguish if the fault was properly corrected, no GS911 required. How quickly do the warning lights flash?

ABS Warning LIghts-1.jpg
Alternate flashing at 1 hz. I see in my Haynes manual that a bad battery can be contributing. Mine is a few years old, but it started the bike 3x today and did not cause the dash clock to re-set, which usually happens with a low battery. I'm charging it now and will see if that helps.
Where in the dickens are them microswitches? :p
Front one is inside the pivot point of the hand lever; rear is behind the footbrake lever.
Both are slightly adjustable; may be that a wire is just broken right there at one of 'em.
The rear microswitch is the more problematic of the two, as it can easily collect crud or get out of alignment. You can check operation by slowly activating the pedal or handlever and listen for a “click” as the switch activates—it will be very near the beginning of pedal/lever movement. If you don’t hear the click the microswitch may be staying engaged, in which case the self-diagnostic at startup can’t complete and you get blinky lights.

As noted, low battery voltage can also trip the lights, and the lights will usually go out if the bike is ridden a few miles, turned off, and restarted. Also, it sometimes helps the diagnostics to complete if you delay a few seconds between turning on the key and pressing the start button.

I don’t know of any way to get good results bleeding the iABS systems without running through the full process—when the front or rear master cylinder reservoir fluid looks dark it’s time to do the entire bleed process top to bottom.

Double check the fluid level in the power circuits.
Should be at the top of the plastic cross bar.
Are both 2 pin level connectors plugged in correctly?
Double check the fluid level in the power circuits.
Should be at the top of the plastic cross bar.
Are both 2 pin level connectors plugged in correctly?

Fluid levels are all correct. Neither connector has ever been unplugged. I'm going to see if I can get someone locally with a code reader to cancel the code and hope that solves this annoying problem. ABS is working. I can hear it whine. All seems well, except for those dadgum flashing red lights on the dash! I charged up the battery, then disconnected the ground for a minute, reconnected it and - no change.
ABS is working. I can hear it whine.

I believe the whine you hear is the brake servo. Your ABS may or may not be working. Ride out to a secluded road, speed up to 60 MPH, grab the front brake lever for all you're worth and see if the ABS kicks in. On second thought, don't - if it's not working you could end up on your head.

Get the fault checked.

To get to the control circuit bleeder valves, we had removed the ABS control module connector. Apparently when we put it back on, one of the skinny wire pins coming up from the ABS unit got pushed down rather than inserting into its female hole on the connector. (guess which pin :p)
Fortunately, the pin did not break or bend, just got pushed down. We pulled it back up with a pair of needle nose pliers, nudged it into perpendicular, then put dielectric grease on all mating surfaces to ease reconnection and very carefully pushed the connector back on, making sure it did not cock one way or another. No more blinkylights. YAY!
Good job. The bleed process goes much smoother with that connector out of the way, but those fragile little pins can be damaged.