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PERMANENT ABS Low Voltage Solution


CoolTouch

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Hello All,

 

I just wanted to share a mod that I did on my 1996 R1100RT to solve the annoying low voltage fault on the ABS systems. It is a joy to not have to play roulette and see if I will get that annoying low voltage fault when I know there is no low voltage problem.

 

PROBLEM: You go and start the bike and instead of getting the two ABS lights on the dash blinking in unison at a one second interval, you get them flashing one at a time indicating (spuriously) that there is a low voltage fault. You can either a) try and start the bike again and try your luck and see if it does it or not, b) ride away and just not have the ABS for that ride, c) ride away and turn ignition off and then pop the clutch to start the bike, or d) find a way to delay the ABS test to when there is ample voltage. Oh yeah, you can also change your battery thinking that will take care of it... I have the OEM battery, an Odyssey battery and an aftermarket battery that provided more amp hours than the others and it lasted the longest before giving me the problem.

 

I chose D, after buying a collection of batteries. Here is the reason this problem happens: The power to the ABS module to perform the low voltage test comes at the moment the battery is at maximum load, at startup. So, there really is no low voltage problem, the battery is just busy starting up a high compression boxer engine! And most any battery that is older than a few months will cause the low voltage fault in the ABS due to the reason I stated above.

 

SOLUTION: If the low voltage test were delayed to when the voltage was nice and stable, that would eliminate the problem permanently. Here is the mod I did, click here:

 

http://ibmwr.org/r-tech/oilheads/ABS-II_low_voltage_modification/index.shtml

 

This is a step by step guide with schematics and part numbers and pictures that is very well thought out. I used a different BMW relay that I happened to have, it doesn't have to be the one they show. I also noticed that it MAY be possible to remove the ABS module connector WITHOUT removing the gas tank. I had mine off because I was doing other things that required it to be off.

 

Basically what this mod does is cut into the circuit that will initiate the low voltage test. It then uses the relay to close that circuit but it powers the relay off the D+ terminal on the alternator which only provides power after the engine is running thus eliminating the non existing low voltage reading.

 

Has anyone else tried this ingenious fix? I found it quite easy to perform, but I also had soldering irons, crimp on connectors, heat shrink tubing and multi colors or hook up wire. I am curious if there is any plausible (relevant) reason that this is not a good idea.

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The low-voltage ABS fault on the R1100 bikes is well-known, and annoying. I applied the above fix and it worked perfectly for many years (before I ultimately sold the bike.) One of the best mods I ever made, never had to play with restarting the ABS system ever again.

 

The only possible downside is that you lose ABS functionality if the engine should stall, but this is extremely unlikely to ever cause a problem in the real world.

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Morning CoolTouch

 

Yes, as mentioned, that is long known fix (been around for years & years) & does work good. (been posted here many/many times)

 

I usually choose a much simpler fix & that is-- you just put a momentary push button switch in that green wire. That allows a simple ABS re-set ANYTIME even riding.

 

The push button also allows full OEM ABS light operation so the ABS dash lights still function as a battery condition test.

_________________________

 

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Morning CoolTouch

 

Yes, as mentioned, that is long known fix (been around for years & years) & does work good. (been posted here many/many times)

 

I usually choose a much simpler fix & that is-- you just put a momentary push button switch in that green wire. That allows a simple ABS re-set ANYTIME even riding.

 

The push button also allows full OEM ABS light operation so the ABS dash lights still function as a battery condition test.

_________________________

 

Dirt Rider----Could you be more specific ---green wire? Looking at the diagram I'm not sure where the momentary switch would be installed?----and is that momentary contact switch normally closed and opens momentarily when you push it-----or is it normally open and closes when you push it?

 

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Afternoon Fraidycat

 

It goes in the green wire between the ign switch & terminal 15 at the ABS controller. (I just install in terminal 15 green wire at the ABS controller (large plug) then run pig tails out to my added switch ).

 

The switch is N/C & push to go open.

 

System works same as OEM normal but (IF) / (WHEN) it defaults a simple push of the button forces a re-set. If engine is running & alternator charging then the re-set happens at a higher voltage than key-on prior to engine start.

 

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I usually choose a much simpler fix & that is-- you just put a momentary push button switch in that green wire. That allows a simple ABS re-set ANYTIME even riding.

_________________________

 

Why would you do that after all the work it took to get to the green wire? If you ever want to go back to OEM, you simply plug the two wires together that you extended to reach the added relay. There is nothing noble in working harder instead of smarter... this is far more elegant than a switch you have to remember to hit every time.

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Evening CoolTouch

 

Still much easier to just add in the switch. There is no need to wire in a relay, no need to access & cut into the alternator D wire, it also allows an anytime re-set so no need to restart the engine to get an ABS reset.

 

Plus-- If you ever want to go back to OEM, you simply DO NOTHING, or to remove the switch just hook the two wires together that you extended to reach the added switch.

 

So there is a valid reason & gain in working smarter than harder if you get the system control you want.

_________________________

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szurszewski
Evening CoolTouch

 

Still much easier to just add in the switch. There is no need to wire in a relay, no need to access & cut into the alternator D wire, it also allows an anytime re-set so no need to restart the engine to get an ABS reset.

 

Plus-- If you ever want to go back to OEM, you simply DO NOTHING, or to remove the switch just hook the two wires together that you extended to reach the added switch.

 

So there is a valid reason & gain in working smarter than harder if you get the system control you want.

_________________________

 

And if your bike is like mine, you only get the ABS fault in certain conditions (sitting for an extended period, sitting for not so extended period but with additional drain like when I leave lights on for awhile or leave my phone/tablet plugged in to charge), and then you only need to push the button/reset the ABS on occasion.

 

 

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