ABS lights alt flashing - DIY?

[TimberGuy]

Following major winter overhaul of '97 R1100RT I now have ABS dash lights flashing (alternately) at me - while riding at speed and after reset button & restart tries. Guidance on what I should be looking for to fix appreciated. Not flashing on first test runs after overhaul as I tracked down a brake light that was constantly lit - that turned out to be foot pedal switch that was improperly positioned (easily fixed). Bike has RT-P wiring harness from previous owner rebuild. Looking for brake light issue I disconnected & cleaned 2 elec plugs on right side above rear brake reservoir (one of these being the pedal switch, don't know what other is yet). Thought it might be low battery drained as I worked on lights, but overnight trickle charge didn't stop flashing indicator lights. Overhaul included purge of all brake lines, but nothing done to ABS control module other than surface cleaning. Rebuild was lots of fun & rewarding, hate to have to take to dealer now as everything else running aces. Kudos to Doc - bike has 148K miles and runs fantastic. Thanks in advance.

[T__]

Randy, sounds like you need to do a proper ABS re-set (at least start with that)

 

 

 

Find your the diagnostic connector (located under the seat)..

 

 

Insert one end of a wire into the middle socket of this connector..

 

Ground the other end of that wire to a (clean) metal part of frame or good CLEAN ground area (make sure it stays grounded)..

 

Turn on ignition. You should see the warning lights flash alternately..

 

Hold ABS button down for about 8 seconds. The bottom ABS light will stay on, and the top one off..

 

Release the ABS button. If you have successfully reset the ABS, both ABS lights will come on.. If you have failed to count to 8, or your ground is not good, the top ABS light will stay off..

 

After the ABS re-set ride the bike.. If the ABS lights come back on pay particular attention to EXACTLY when they come on,, like at engine start,, at ride away,, or after moving a short ways.. That might tell us where to look for the problem..

 

Twisty

 

[boatzo]

Randy, you should do an ABS reset procedure. The ABS button is not a reset, it deactivates the ABS. After your wiring work, this reset needs to be done.

 

On the diagnostics connector under the seat, remove same from the block off connector.

 

Insert one end of a wire into the middle socket of this connector

 

Ground the other end of the wire to a good clean ground and fix it so it stays grounded.

 

Turn on the ignition. Lights should flash alternately

 

Hold the ABS button down for min. 8 seconds. The bottom ABS light will stay on and the top should be off

 

Release the ABS button, both ABS lights should come on if you did it right. If you didn't get at least 8 seconds or you ground wasn't good, The top light will stay off.

 

Hope this helps, let us know.

 

 

I just posted and see that Twisty beat me to it. That is the kind of great response you get on this forum. Twisty, I think you type faster than I do.

[Joe Frickin' Friday]

Before you clear the fault code, read it.

 

From IBMWR.org's Oilhead Maintenance Manual, page 72:

 

===================

ABS II:

- voltmeter on pin 2

- turn ignition on

- meter will indicate about 11V steady with no faults stored

- count eventual dips towards zero volts

- fix the cause of the fault and cancel code

 

ABS II Codes:

1 front pressure modulator

2 rear pressure modulator

3 front sensor

4 rear sensor

5 battery voltage low

6 ABS relay

7 ABS control unit

8 sensor gap front or rear

 

ABS II Canceling Error Codes:

this has been reported before. Just for reference:

- ground pin 2

- switch ignition on

- push ABS button for at least 8 seconds

- release ABS button

- switch ignition off and remove ground from pin 2

 

Notes:

- I remember having seen a code 9 once, but cannot remember to what it

belongs

- ABS can store only one fault at a time

- codes 1 - 4 are latching, i.e. they don't go away automatically once the fault is

fixed

- codes 5 - 9 are self-canceling as soon as the ignition is switched off and on

again ( the fault does not persist!)

- the ABS output signal will need some filtering due to short spikes

Most of the information given above comes from the BMW booklet “BMW

Diagnose - Test Instructions for Antilock Braking System (ABS)”, # 0171 9 798

811 (5.90). The booklet is about the ABS I, but seems to be valid for the ABS II

as well.

=====================

 

 

[TimberGuy]

Thanks all - tis great to have fellow enthusiasts with brains to pick, making up for those of us with slower faculties.

 

Will try the reset and let you know - won't get to it for a couple days sadly.

[TimberGuy]

Fellas,

Still have questions.

Trying to 'read codes' I got a constant 5.5 - 5.8 volts at pin 2.

So went ahead and reset; assumed a problem would come back with another fault code.

Took for ride around neighborhood and no more flashing lights - assume that is good sign.

Q - why no fault code readings?

Mostly happy, but inquiring minds want to know.

[T__]

Randy, you really need an old needle type analog volt meter,, if you used a modern digital meter the response is usually slow enough to not track with the dips..

 

I wouldn’t worry about the stored codes with all the work you did to the bike & the low battery & all I seriously doubt that it stored any useful codes that were real malfunctions..

 

Best to just clear the darn thing the start over,, that way if you trap a new stored code it will be recent & a present malfunction..

 

Go ride it & if it doesn’t trap any new failures it probably was just spoofed by fluctuating battery voltage or some of the work you did..

 

Twisty

 

[boatzo]

Great news Randy, glad the reset worked. Hope you enjoy your new toy. With all the work you did on it, it gives you a real rewarding

feeling.

[Joe Frickin' Friday]

Fellas,

Still have questions.

Trying to 'read codes' I got a constant 5.5 - 5.8 volts at pin 2.

So went ahead and reset; assumed a problem would come back with another fault code.

Took for ride around neighborhood and no more flashing lights - assume that is good sign.

Q - why no fault code readings?

Mostly happy, but inquiring minds want to know.

 

As noted, an analog meter is best for reading fault codes.

 

FWIW I've had latching faults before that, once reset, never returned. If your ABS system is now fault-free, I'd say run with it until/unless a fault code pops up again.

[philbytx]

Randy,

Just one thing....you said you never touched the ABS unit except for external cleaning. Does that mean you never did a bleed on the ABS unit? If you still have the bike semi-stripped, I would definitely bleed it out. There are only two bleeders on it and it doesn't complicate the procedure any to bleed it out.

Several of us with ABSII bikes have done this bleed, after the basic bleed, and all had grungy fluid come out of the ABS unit.

 

Then again, I am anal!

 

 

 

[TimberGuy]

I did NOT bleed the ABS unit separately. Read conflicting advice about it, imagine that! Thought the lines thru ABS were between reservoir and caliper, so that a purge/bleed would get those lines also. (Recall this is a '97 model.)

 

Good news. ABS reset worked fine - no new fault code has appeared. Brakes seem to be working great, daily hard braking practice. This bike now has 148,000 miles on it and is as happy as I am.

 

Impressions post-rebuild.

1) Really valuable exercise, everyone should do it.

2) Tremendous confidence boost for rider - to be able to sense & fix many troubles.

3) Required mechanical aptitude is only moderate except for driveline, tools basic.

4) Bike runs better than I've known since acquisition Feb '09.

5) Noticeably more power which I attribute mostly to clean plugs, throttle bodies & air channels.

6) BMW parts are very expensive and its nice to find/make alternatives.

7) Glad I moved fuel filter out of tank (to behind & below right TB) and use generic filter.

8) Machines have souls and like to be fondled and cleaned.

9) Looking for riding school to rebuild the rusty nut holding down the seat.

 

Thanks for everyone's input - sharing with the network is half the fun.

[boatzo]

Great news Randy. This has been a good thread. Enjoy your ride for many more miles.