ABS I question

[Mudbug]

Now that I have a new battery, thanks to your recommendations, I need help with the ABS I.

My local dealer tested the ABS I unit and declared that it was "bad." So I replaced it when I replaced the battery.

When travelling, the ABS light and the triangular light both blink, at the same time. I replaced the ABS I unit and it still does it. If I press the ABS switch, they both stay on steady for 10 minutes then they both start blinking again.

Will resetting, as described on IBMWR, solve my blinking problem? :confused:

[kioolt]

Resetting may solve your problem. I've had my 91 K100LT since new and twice the ABS light has come on in 116K. The first time was under warranty and the dealer reset it. The second time was a couple of months ago and I reset it according to the IBMWR site. As for the lights coming on steady for 10 minutes after you press athe ABS button that is normal. The tech articles on the IBMWR site helped me alot when my bike did it the second time. Total cost for the repair was nothing.

[bmwmick]

Robert,
If you got a good ABS unit, the reset should work. If the blinking comes back, readout the codes and let us know what you find.
Mick

[deilenberger]

Originally posted by Mudbug
Now that I have a new battery, thanks to your recommendations, I need help with the ABS I.

My local dealer tested the ABS I unit and declared that it was "bad." So I replaced it when I replaced the battery.

When travelling, the ABS light and the triangular light both blink, at the same time. I replaced the ABS I unit and it still does it. If I press the ABS switch, they both stay on steady for 10 minutes then they both start blinking again.

Will resetting, as described on IBMWR, solve my blinking problem? :confused:

It may or may not - but if you read the rest of the tech pages on ABS-1 on the IBMWR site, you can see how to determine *what* is wrong.

The dealer may have read a code-7 when they decided to replace the ABS brain. Sometiimes that accurately reflects that the brain has actually failed, and sometimes not.

I seem to be seeing a correlation between low battery voltage and brain failures.

If you read out the code and pass it along, we perhaps can guide you in fixing the system.

If the first reset doesn't "take" - try doing it again, but hold the ABS button down for 60 seconds. There is an undocumented LONG reset that sometimes works when the regular one doesn't.

And I'd be interested in seeing the ABS brain the dealer replaced.. I'm collecting bad ones to see if I can spot a common failure point in them.

Best,

[Mudbug]

I tried to reset my ABS to no avail.

I followed the instructions on IBMWR - nothing.

This is what I have. When I turn on the ignition, the lower left red "ABS" light flashes. The center red "triangle" light is on steady. In the instructions it says, "Note that the two ABS lights flash alternately." That is not what is happening on my bike.

Once I get moving at normal speed and use the brakes, both lights flash in unison.

As described in the instructions, grounding the " middle socket hole " does not work for me.

Any suggestions.

[deilenberger]

Originally posted by Mudbug
I tried to reset my ABS to no avail.

I followed the instructions on IBMWR - nothing.

How long did you do the reset for? See my post above for why I'm asking.


This is what I have. When I turn on the ignition, the lower left red "ABS" light flashes. The center red "triangle" light is on steady. In the instructions it says, "Note that the two ABS lights flash alternately." That is not what is happening on my bike.


The center one stays on steady UNTIL you use both brakes. It tests the brake switches and the brake light bulb (and actually the rear running light).



Once I get moving at normal speed and use the brakes, both lights flash in unison.


If they continue flashing after reaching ~ 5MPH, then you have a fault.


As described in the instructions, grounding the " middle socket hole " does not work for me.

Any suggestions.

Please:

1. Explain exactly how you performed the reset.

2. Tell me how long you kept it grounded and held down the ABS switch for.

3. Consider reading the rest of the ABS-1 FAQ pages and if the long reset I described in another posting here doesn't work - then read out the error codes.

If there is a flaw in the system - without knowing the error code (and we're not psychics or magicians) - we have no way of giving you more guidance.

Best,

[Mudbug]

I tried both of the reset instructions found on the IBMWR site, which I won't repeat here.

http://www.ibmwr.org/ktech/abs-reset.shtml

and

http://www.ibmwr.org/ktech/abs-reset2.shtml

I also tried the long reset described earlier.

Now I'm going to try to read the error codes as described in http://www.ibmwr.org/ktech/abs-diagnostics.shtml

I have a question so far. "If an open is indicated, check the wires from the brain plug to the Modulator plug." Which is the brain plug and which is the Modulator plug?

[bmwmick]

Robert,
The modulator plug is at the modulator, 3 position if I remember correctly and the 'brain' plug is at the ABS control unit, 25 position connector.

HTH,
Mick:brow

[Mudbug]

Is the modulator in under the gas tank?

[bmwmick]

Originally posted by Mudbug
Is the modulator in under the gas tank?

Robert,
The modulators on an ABS-I bike are mounted to the footpeg brackets, one on each side of the bike (except for the K1 which had the rear modulator exposed but the front modulator was hidden in the upper left fairing).
They look like big (5" diameter) motors. Actually they are large solenoids. When the ABS control unit commands a release of brake pressure to get a wheel rotating again, the modulator 'cycles' which releases the pressure being applied to the offending wheel momentarily.

The black thing with ABS on it in this picture is my right side (rear) ABS Modulator.


Mick

[CustomSarge]

I'm not going to go Too crazy here: MY Suspicion:
1> System initialization, should be AFTER the engine run / disable starter signal is stable.
2> Owned : a> R12C; bought new, bad init 1/5 times, dealer says "check battery" $60. later: "OH" not the problem & no indication of what IS.
b> K75RT ; bad init at start, dealer diag: replace cpu=1k$, NOT!
c> K11LT; bad init at start, dealer diag: replace cpu+1k$, NOT!
d> R11RT; bad init at start (not paying for diag), pull entire system from bike, TFB! (got parts!)

> I'm not impressed with the system as currently produced. I don't want their job doing this, but I'm not a fan of their foisting their "doughy" concepts on me either. I'm responsible for electro-mechanical systems designs for museums & other 1(+) pop scenerios. Multi-thousand production quantities have aspects I don't know (nor want to). I'd like to think there is a consolidated / compromising area where we can level this all out...... <<<)))

[deilenberger]

Originally posted by Mudbug
I tried both of the reset instructions found on the IBMWR site, which I won't repeat here.

http://www.ibmwr.org/ktech/abs-reset.shtml

and

http://www.ibmwr.org/ktech/abs-reset2.shtml

I also tried the long reset described earlier.

Now I'm going to try to read the error codes as described in http://www.ibmwr.org/ktech/abs-diagnostics.shtml

I have a question so far. "If an open is indicated, check the wires from the brain plug to the Modulator plug." Which is the brain plug and which is the Modulator plug?

Robert - as others have pointed out - the modulators are kinda staring at you (they do have a big ABS logo on them..)

The ABS brain is located in the rear pod behind the seat. It's a bit tricky to get out, but it is doable.

If you start probing for faults - especially on the ABS brain - probe the connector from the back. There is probably a screw and tie-wrap that have to be removed to remove the cover over the connector. If you probe from the connection side - be VERY careful to NOT BEND the contacts on the connector.

The modulator connectors are normally found tie-wrapped to the upper frame tube under the seat. A big clue for finding ABS-1 connectors (and relays) is they are ALL blue (and no other connectors on the bike are).

Read out the codes - and then there are more detailed diagnostics on reading resistance values and voltages that you can do if it indicates other than a brain fault. - I see you've already found that.

Good luck and let us know how it works out..

[EastTNBeemer]

I don't know if this will help, but here goes......

I have a 92 K75S and had the same trouble you describe. I reset the ABS "brain" as per the ibmwr site and still had flashing lights. Now, when I start up, I rev the engine a little before putting the bike in gear to start moving. No more problem. Maybe the battery is a little weak and revving give the electrical system a boost to properly reset the ABS? I don't know, but it works every time.:clap

[Mudbug]

Regarding my ABS I fault problem on my 1991 K100RS.

I bought a cheap volt/ohm meter from Home Depot. Following the instructions, namely the fourth paragraph in http://www.ibmwr.org/ktech/abs-diagnostics.shtml, I think I found the problem, emphasis on THINK.
The meter pulsed 2 times. But then it seemed to pulse by itself after the test when it was not connected to anything. Hummmmmm !?

Anyway, I tried a driving test. I found that if I do not use the rear brake when stopping, the ABS light flashes and the "delta" center light stays on constantly. When I use the rear brake, both flash. Does that mean that there is a problem with the rear something-or-other? Me thinks so.

I did not find any blue connectors.

[deilenberger]

Originally posted by Mudbug
Regarding my ABS I fault problem on my 1991 K100RS.

I bought a cheap volt/ohm meter from Home Depot. Following the instructions, namely the fourth paragraph in http://www.ibmwr.org/ktech/abs-diagnostics.shtml, I think I found the problem, emphasis on THINK.
The meter pulsed 2 times. But then it seemed to pulse by itself after the test when it was not connected to anything. Hummmmmm !?

Anyway, I tried a driving test. I found that if I do not use the rear brake when stopping, the ABS light flashes and the "delta" center light stays on constantly. When I use the rear brake, both flash. Does that mean that there is a problem with the rear something-or-other? Me thinks so.

I did not find any blue connectors.

The driving test just proves your brake/driving light bulb monitor is working.

PLEASE READ YOUR OWNERS MANUAL.

The behavior of the central light staying on constantly UNTIL you use BOTH brakes is normal. Only after you use both brakes and all the bulbs are OK does it turn into an ABS warning light.

If you didn't find any BLUE connectors it's possible you haven't removed the tank yet. That will be part of the fix so you may as well do it now.

The modulator connectors are blue. The relays in the electrical box for the ABS are blue. ALL of the ABS connectors with the exception of the one to the ABS brain are BLUE.

As far as the cheapy meter from Home Depot - it probably isn't suitable for the use you're putting it to. An analog meter (one with a dial and a pointer) is much better for reading the codes. An LED tester - as described in the IBMWR faqs on reading the codes is much better.

The reason is - time constant and input impedence. I won't try to explain all this to you - but will stress that it appears you may or may not have read a code #2. If you used an LED code reader I'd be much more confident of the code.

The semi-good news is - if you did read the code correctly, you can now do further diagnostics to determine if the rear ABS modulator is indeed dead. If it is - it's not a terribly expensive repair since these really never seem to fail, so used ones are very cheap.

The diagnostics you need to do are in the same article by Brian Curry:

===========================
Fault Code 2 - Rear Pressure Modulator ABS connector pins of interest 7,11,12
Test Value resistance
Resistance 7-11 ~4.48 K-ohms
Resistance 7-12 ~16.7 K-ohms
Resistance 11-12 ~19.5 K-ohms

If an open is indicated, check the wires from the brain plug to the Modulator plug. If those connections are OK, the modulator is bad.

Remove the ABS relay in the electrical box under the tank. The relay is at the front of the box, on the left side, just beside where the front wiring harness enters the box. Measure resistance from the ABS relay socket to ground. Measure from 87 to frame ground. It should measure 17.4 K-ohms.

Again, if it is open check from the socket to the Modulator plug. Then check from Terminal 31 of the Modulator to ground. Again, if the wiring is good, the modulator is bad.

With the ignition off, the ABS relay socket connection Pin 30 should be the same as the battery voltage. If not, check that connection point is secure, and the red wire from the battery to connection point 30.
===========================

The important measurements are the resistance ones - and you measure these at the BLUE connector that you'll find on the right side or under the tank on the right side. It is an oval shaped connector, BLUE in color.

Once you've made the measurements get back to us with the results. Take some care that you read the meter correctly. Lots of digital meters indicate multiples of Ohms (such as K-Ohms, or kilo-Ohms, or 1,000 x # Ohms) with a small indicator. Some digitial meters display large mutliples of Ohms (such 100,000 Ohms) as a factor of Meg-Ohms - which means 1 Million Ohms. 100,000 Ohms might display as 0.1 MOhms.

If the modulator is indeed bad - then you can check on both Ebay and the IBMWR marketplace. Used ones are frequently seen for less than $100.

If all of this is confusing - it might be time to visit a dealer. I consider brakes to be a primary safety system, and if you're not comfortable working on them, a dealer is who you should see.

Oh - here is the link for making your own LED fault code indicator:

http://www.ibmwr.org/ktech/abs-fault-readout.shtml

It is small enough to carry on the bike, and can be made from $2.00 of Radio Shack parts.

Best,

[Mudbug]

Don,
Thanks for all your suggestions and help. I'm determined to do this myself. I don't trust the dealer's diagnosis. I want to do my own diagnosis.

I'm off to RadioShack for the led, resistor, stuff to put it together, and a decent volt/ohm meter, analog as you recommended.

I've been very cautious because of differences between what I seen in some of the online descriptions and what I see on my bike.

[deilenberger]

Originally posted by Mudbug
Don,
Thanks for all your suggestions and help. I'm determined to do this myself. I don't trust the dealer's diagnosis. I want to do my own diagnosis.

I'm off to RadioShack for the led, resistor, stuff to put it together, and a decent volt/ohm meter, analog as you recommended.

I've been very cautious because of differences between what I seen in some of the online descriptions and what I see on my bike.

Robert - sounds good. Let us know what you find out when you read the code with the LED.. and I can understand wanting to do your own diagnostics.. I think way too many dealers have unnessarily replaced parts based only on the diagnostic codes.

Best,

[Mudbug]

I have successfully read the ABS I fault code. :clap It is 2, - "Fault Code 2 - Rear Pressure Modulator."

I built my own ABS fault code test box using a jpg posted at http://www.xs4all.nl/~hkuijer/jpg/Motronic/pages/P9140943.htm
I went to RadioShack and purchased the parts. I used RadioShack part # 2760272, and orange LED with resistor built in a holder. All they had was green or orange. Since color was not important, I chose orange. I added a small on/of switch 2750624 and a small black project box 2701801. I soldered and assembled it together and immediately tried it out. It worked great. :D

Now I have to learn how to take the tank off. I'll try it when the tank is almost empty.

Now for the best part of all this, it's time for a beer.

[bmwmick]

:clap :clap :clap :clap :clap

Congratulations Robert!!

Mick

[deilenberger]

Originally posted by Mudbug
I have successfully read the ABS I fault code. :clap It is 2, - "Fault Code 2 - Rear Pressure Modulator."

COOL!


I built my own ABS fault code test box using a jpg posted at http://www.xs4all.nl/~hkuijer/jpg/Motronic/pages/P9140943.htm
I went to RadioShack and purchased the parts. I used RadioShack part # 2760272, and orange LED with resistor built in a holder. All they had was green or orange. Since color was not important, I chose orange. I added a small on/of switch 2750624 and a small black project box 2701801. I soldered and assembled it together and immediately tried it out. It worked great. :D


Actually - the one with the resistor can be used like it is to check faults. I'm guessing you added the switch to take the diagnostic port to ground for a reset?


Now I have to learn how to take the tank off. I'll try it when the tank is almost empty.

Now for the best part of all this, it's time for a beer.

Yup - next step is to check the resistances on the modulator connection points. Once you do that (and your digital meter or an analog one should work fine) - get back to us with the results!

Best,

[Mudbug]

Actually - the one with the resistor can be used like it is to check faults.

You are correct. The LED with resistor built into the holder would do by itself. But I wanted to build a nice tool complete with box.

[Mudbug]

Recently my 91 K100RS, needed a rear bearing and new drive shaft, new rear seals, clutch and a few other things. It was an expensive repair.

One unexpected result is that the ABS I now works. It no longer shows a fault. No blinking of the ABS dash light. It works as expected. Originally, I thought that it was a rear modulator. The dealer wanted to replace the ABS I brain as a posible fix. It turn out to be a loose or dirty connecton to the rear pickup/sensor. The dissembly and reassembly of the rear end fixed the problem.

:thumb