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#1003551 - 01/13/18 12:50 AM Another ABS thread Code #7  
Joined: Nov 2016
Posts: 44
MB_ED Offline
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MB_ED  Offline
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Bethesda Md
Hello all,
I'll try to give as many details as possible. 1995 R1100RS I borrowed this bike in May of 2016 for a trip to NC. The ABS lights would blink alternately after engine start, I could hit the ABS button on the left dash and stop them for a bit, until they started again. I put a piece of tape over the lights so I didn't have to look at them while on my trip. The brakes seemed to be working fine as conventional brakes and I mentioned it
to the guy that owned it at the time.
A few months later (Nov 16) this bike becomes mine, complete with alternating ABS lights. I look around on the interwebs, read all kinds of information about low voltage and it's probably my battery. I charge and check the battery, it's good. I notice the starter seems to be having a hard time turning the engine until one day it took a crap so I replaced it thinking maybe that was the starter was the reason for the ABS lights. NOPE! still doing the same thing.
Now I try to clear any faults in the ABS and find out that 2 owners ago he had done the "low voltage modification" as described here http://www.ibmwr.org/r-tech/oilheads/ABS-II_low_voltage_modification/index.shtml
Since I knew this owner as well, I wasn't concerned about the quality of the modification. He did it by the numbers and it worked for him. This was done in August of 2010 at 70,000 miles. It was working until about 75,000 miles. Since it's had the mod any code reading or clearing must be done with the engine running.

I've gotten around to reading the code and it's #7. I can't clear it, it will not go away. The relay for the mod clicks right after start up ~1000-1100 RPM the lights alternate until I hit the button then the bottom light stays lit. The code says ABS control unit. I've found no diagnostics so I'm lost at this point.

The bike did sit for a couple of years when owner (1) was diagnosed with cancer and stopped riding. Owner (2) didn't ride it much, a little too heavy for his liking. I've been riding it since Nov, '16 pretty constant.
I've never heard any noise from the pump in all of the time I've been riding the bike

What steps can I take at this juncture?
Thanks in advance,
Ed

Last edited by MB_ED; 01/13/18 12:58 AM.

1995 R1100RS
1997 Shadow VLX (sold)
1984 Magna 700 (for sale)
1989 Virago Route 66 (the trainer)
1986 VFR 750 (project)
#1003570 - 01/13/18 05:00 AM Re: Another ABS thread Code #7 [Re: MB_ED]  
Joined: Sep 2003
Posts: 763
Michaelr11 Offline
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Michaelr11  Offline
Member

Joined: Sep 2003
Posts: 763
Trinity, NC
When the lights are flashing alternately right from the start, the ABS2 is already in an error condition and it will not perform a self-test. If you can clear the fault code, the next time the bike is turned on, the lights should be flashing together. Then, when you roll off, the ABS should self-test and either the lights go out and it is functioning normally or the lights start alternating and you want to read the error code.

If you truly have a code 7 ABS control unit error, then I would send the unit off to Module Master for a repair. They do repair the ABS2 units and warranty the repair. Your other option would be a used ABS2 unit but that is likely as expensive or more than the cost of the repair.


Michael Stock, Trinity NC
01 R1100RT, R60/6, R100
#1003574 - 01/13/18 11:52 AM Re: Another ABS thread Code #7 [Re: MB_ED]  
Joined: Jun 2010
Posts: 13,322
dirtrider Offline
The Oracle
dirtrider  Offline
The Oracle
Member

Joined: Jun 2010
Posts: 13,322
Ohio
Originally Posted by MB_ED
Hello all,
I'll try to give as many details as possible. 1995 R1100RS I borrowed this bike in May of 2016 for a trip to NC. The ABS lights would blink alternately after engine start, I could hit the ABS button on the left dash and stop them for a bit, until they started again. I put a piece of tape over the lights so I didn't have to look at them while on my trip. The brakes seemed to be working fine as conventional brakes and I mentioned it
to the guy that owned it at the time.
A few months later (Nov 16) this bike becomes mine, complete with alternating ABS lights. I look around on the interwebs, read all kinds of information about low voltage and it's probably my battery. I charge and check the battery, it's good. I notice the starter seems to be having a hard time turning the engine until one day it took a crap so I replaced it thinking maybe that was the starter was the reason for the ABS lights. NOPE! still doing the same thing.
Now I try to clear any faults in the ABS and find out that 2 owners ago he had done the "low voltage modification" as described here http://www.ibmwr.org/r-tech/oilheads/ABS-II_low_voltage_modification/index.shtml
Since I knew this owner as well, I wasn't concerned about the quality of the modification. He did it by the numbers and it worked for him. This was done in August of 2010 at 70,000 miles. It was working until about 75,000 miles. Since it's had the mod any code reading or clearing must be done with the engine running.

I've gotten around to reading the code and it's #7. I can't clear it, it will not go away. The relay for the mod clicks right after start up ~1000-1100 RPM the lights alternate until I hit the button then the bottom light stays lit. The code says ABS control unit. I've found no diagnostics so I'm lost at this point.

The bike did sit for a couple of years when owner (1) was diagnosed with cancer and stopped riding. Owner (2) didn't ride it much, a little too heavy for his liking. I've been riding it since Nov, '16 pretty constant.
I've never heard any noise from the pump in all of the time I've been riding the bike

What steps can I take at this juncture?
Thanks in advance,
Ed


Morning Ed

Have you tried re-setting the ABS?--


Find 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 ground area (make sure it stays grounded).

Turn on ignition. You should now 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 should be off.

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


You will have to either figure out how to do the re-set with your engine-running ABS modification, or temporarily by-pass the ABS modification to do the ABS re-set.

As far as troubleshooting procedures?-- There really isn't much as the diagnostic output on the old ABS-2 system is very limited.

If the re-set doesn't work & you want to do some testing then you might verify that the ABS module power relay (under the side cover on the ABS module) is working & switching 12v B+ when it's energized (just clicking only tells you it is energizing not that it is REALLY working)-- I have seen a number relay failures on older bikes that have been parked for a long time.

You might also verify that the ABS modification is still working as that might have a broken wire, high resistance in a circuit, or relay failure.

If you can somehow track the failure to the ABS modulator itself (eliminate all the external electrical possibilities) then you are possibly dealing with a stuck internal piston or a motor issue. Sometimes a stuck piston can be freed up with a rubber mallet & rapping on the outside of the ABS modulator or by triggering a power on/off/on/off/on on the green wire into the ABS module while riding on a very rough washboard road.

Otherwise your options are to remove the ABS system & revert the bike to non-ABS brakes, or buy a good working used ABS modulator, or send your modulator out for repair, or remove your modulator & take it apart & see if you can find & repair the problem.


D.R. ___
Sent from my rotory dial wall phone!
#1003580 - 01/13/18 02:43 PM Re: Another ABS thread Code #7 [Re: dirtrider]  
Joined: Nov 2016
Posts: 44
MB_ED Offline
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MB_ED  Offline
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Joined: Nov 2016
Posts: 44
Bethesda Md

Michael, thank you for the reply, I have never seen the lights flash together since owning the bike.

DR, Yes sir I have tried resetting the ABS with engine running and not running with no success. I will try again though. I had thought about a stuck piston in the modulator. I'll look at the power relay relay as well as check the wires for the modification when I get back to the shop. Love the bike, been riding for many years and have never had ABS so it's not like I feel I need it but if it's on the bike I'd like it to work.

Thanks guys!!
Ed


1995 R1100RS
1997 Shadow VLX (sold)
1984 Magna 700 (for sale)
1989 Virago Route 66 (the trainer)
1986 VFR 750 (project)
#1003582 - 01/13/18 03:15 PM Re: Another ABS thread Code #7 [Re: MB_ED]  
Joined: Jun 2010
Posts: 13,322
dirtrider Offline
The Oracle
dirtrider  Offline
The Oracle
Member

Joined: Jun 2010
Posts: 13,322
Ohio
Originally Posted by MB_ED

Michael, thank you for the reply, I have never seen the lights flash together since owning the bike.

DR, Yes sir I have tried resetting the ABS with engine running and not running with no success. I will try again though. I had thought about a stuck piston in the modulator. I'll look at the power relay relay as well as check the wires for the modification when I get back to the shop. Love the bike, been riding for many years and have never had ABS so it's not like I feel I need it but if it's on the bike I'd like it to work.

Thanks guys!!
Ed


Morning Ed

A lot of riders have removed the old antique ABS-2 system rather than spend the time & money trying to repair it. The BMW 1100 bikes actually have great brakes with the ABS removed & in some cases better brakes as the slow cycling ABS-2 systems have a habit of suddenly & unexpectedly releasing the brakes during a hard stop on a dry but rough road surface.


D.R. ___
Sent from my rotory dial wall phone!
#1003585 - 01/13/18 04:41 PM Re: Another ABS thread Code #7 [Re: MB_ED]  
Joined: Nov 2016
Posts: 44
MB_ED Offline
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MB_ED  Offline
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Joined: Nov 2016
Posts: 44
Bethesda Md
Thanks DR, the bike has been a pleasure to ride as it is. I've had no issues, it's as if the ABS doesn't exist. (which I suppose technically it doesn't) It's still cold and crappy outside, I'll check this, check that, clean it up a little here and there and be ready for warmer weather. I just did a valve adjustment, tires and oil change. I see some of the harness looms are breaking away so I'll get the harness protected with new loom. I see non-factory wires that previous owners have wire tied in. I want to check them, see where they go, do they have power etc. Basically just clean everything up.

I appreciate the advise and knowledge from the members here

Ed


1995 R1100RS
1997 Shadow VLX (sold)
1984 Magna 700 (for sale)
1989 Virago Route 66 (the trainer)
1986 VFR 750 (project)

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