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toddthom
08-27-2003, 11:29 PM
I have an 1992 K75 RTA and a fault code erroneously created is faulting out the ABS brakes. My BMW dealership claims the ECU needs replacing at 1100.00. WOW!! I aked about a used one but they hav no answers. They said they would look around but I don't hold any hope.
First, has anyone else encountered this ECU problem , second how did you fix it and thirdly has anyone access to a used ECU for a 1992 K75RTA specifically.

Let me know. Thanks

colt03
08-28-2003, 10:39 AM
Todd,

I wouldn't order the new computer yet!

Go to http://www.ibmwr.org/ktech/abs-diagnostics.shtml

This will let you read the fault and then you can go from there. That site also has info to clear the faults. Take first things first, in my four years on the ibmwr mailing list i don't recall of anyone needing to replace the abs brain.

Good luck
Craig Cleasby
South Windsor, CT
96K1100lt

toddthom
08-28-2003, 06:08 PM
Thanks for the reply. I needd to clarify the fault code statement. I just asked the BMW dealer what the fault code was and therewasn't one! The ECU is disabling the ABS and firing off the dash lights without issueing a fault code. This is why they requested replacing the ECU, which they have had to do twice before. So in their experience they have seen this condition.

NOw I think I need to find a K75 RTA ECU which is going to be hard. I can't use any old K75 ECU becauase they are "burned into thee specific model of bike" adn once burned you can't undo the programming - according to the dealer.

Any bopdy out there hear of someone canabalizing an RTA for parts?

LORAZEPAM
08-28-2003, 09:02 PM
Try Re-psychle (I aam not sure about the spelling) motorcycle parts. they specialize in bmw parts, and have a great selection on hand.

toddthom
09-02-2003, 08:05 PM
God I love Dealerships. #$%&^&&%!!! They told me I needed a new ECU to repair the ABS. HuH? Doesn't make real good sense but who am I? I looked into the matter only to find out that the part number they gave me was in fact an ECU for the Fuel injection control. What the ...?? I called back and they corrected themselves by saying I needed an ABS contorl module and they gave me a dfferent part number.

Whew! Got that strightened out and so now I'm looking for an ABS control module for K75 RTA. Any body got one or know where I can find one. I tried re-psycle, Bob's BMW, and others. No joy.

Please help. Thanks

deilenberger
09-10-2003, 02:54 AM
Originally posted by todd thompson
God I love Dealerships. #$%&^&&%!!! They told me I needed a new ECU to repair the ABS. HuH? Doesn't make real good sense but who am I? I looked into the matter only to find out that the part number they gave me was in fact an ECU for the Fuel injection control. What the ...?? I called back and they corrected themselves by saying I needed an ABS contorl module and they gave me a dfferent part number.

Whew! Got that strightened out and so now I'm looking for an ABS control module for K75 RTA. Any body got one or know where I can find one. I tried re-psycle, Bob's BMW, and others. No joy.

Please help. Thanks

Given the incompetancy of the mechanic (remember - they aren't electricians) - I'd <b> STRONGLY </b> suggest going to the website mentioned above and doing the tests described.

I have never seen an ABS-I CPU failure that didn't throw a code. And lots of them that do throw a code can be easily reset and work fine.

PLEASE go read the diagnostics and let us know what code you read out. Then we'll have some needed data to try to help you decide what to do.

Just replacing parts is called "flailing" - and eventually it will fix the problem - but it gets awfully expensive doing it this way.

toddthom
09-14-2003, 02:19 PM
Don, thanks for the advise. This ABS ECU has had a recurring failure for the previous owner and my self. I have had the ECU reset because I thought the previous owner was BS'ing me only to have it fail twice again. The ECU is crippling the ABS and is not putting out any codes - repeat, no codes and lots of light on the dash as you'd expect. This is the problem. Great brakes even without the ABS but I did buy the bikes for the brakes. I was naive to think I could fix them without a replacement of the ABS ECU. SO now I 'm looking for a parts bike that has one.

Win3855
09-14-2003, 10:34 PM
I had that same type of problem on my 97 R1100RT,the ABS system is battery voltage sensitive and a new Odyssey 680 cured that problem. The battery was on the way out. May be the same thing?

deilenberger
09-15-2003, 02:41 AM
Originally posted by todd thompson
Don, thanks for the advise. This ABS ECU has had a recurring failure for the previous owner and my self. I have had the ECU reset because I thought the previous owner was BS'ing me only to have it fail twice again. The ECU is crippling the ABS and is not putting out any codes - repeat, no codes and lots of light on the dash as you'd expect. This is the problem. Great brakes even without the ABS but I did buy the bikes for the brakes. I was naive to think I could fix them without a replacement of the ABS ECU. SO now I 'm looking for a parts bike that has one.

Two questions:

Who read the codes?

Did you try a long reset- same as the reset explained in the IBMWR list - but do it for at least 1 minute.

Best

toddthom
09-16-2003, 11:37 PM
Dealer read the codes - or lack thereof. I don't have the equipment to read codes.

deilenberger
09-17-2003, 03:30 AM
Originally posted by todd thompson
Dealer read the codes - or lack thereof. I don't have the equipment to read codes.

That was kind of what I thought. And since the dealer was about to replace the other brain on the bike I would want to read them myself before trusting their diagnosis and spending $$$ on a new brain.

Go to Radio Shack, ask them for a 12V LED. It will have a resistor built into the package. This is the ONLY diagnostic tool you need - cost will be about $2.

If they don't have a prepackaged one - you can try using just a plain LED. Worst you'll do is blow up the LED (which I doubt a great deal.. the diagnostics port doesn't have enough power to do that).

Then go to this page on the IBMWR K-tech pages:

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

Read the first 4 paragraphs. The diagnostic port is located on your right frame tube, behind the battery panel. The center pin is pin#2. Connect one side of the LED to this pin and the other side to a good ground (usually the LED will have a red lead on it - this is the lead you connect to the pin on the diagnostics port).

Read out the code as described - then report back.

Then you can try resetting the brain yourself, as described in:

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

The only comment I have on this is step 7 - increase your count to 60 (seconds).

Then report back to us. I haven't seen a failed ABS brain that didn't give a code reading.

You can lead a horse to water..

toddthom
09-18-2003, 02:41 PM
Thanks, I'll do it

toddthom
09-23-2003, 08:17 PM
Don, I went out and bought a volt/ohm meter (need one anyway) and made up a jumper cable for the ECU signal terminal.

I turned on the ignition and read 7 blips of my analogue meter needle. I read it again, 7 blips of the needle.

I then followed the instructions to reset the ECU. First time at 8 seconds holding down the ABS button. Same 7 blips. Then 20 seconds. SAme 7 blips. then advising your instructions I help the botton for 60 (yes,with the ignition on) and I get the same 7 blips of the meter needle.

Fried ABS ECU or (hopefully)do you have another trick up your sleeve?

deilenberger
09-23-2003, 08:30 PM
Originally posted by todd thompson
Don, I went out and bought a volt/ohm meter (need one anyway) and made up a jumper cable for the ECU signal terminal.

I turned on the ignition and read 7 blips of my analogue meter needle. I read it again, 7 blips of the needle.

I then followed the instructions to reset the ECU. First time at 8 seconds holding down the ABS button. Same 7 blips. Then 20 seconds. SAme 7 blips. then advising your instructions I help the botton for 60 (yes,with the ignition on) and I get the same 7 blips of the meter needle.

Fried ABS ECU or (hopefully)do you have another trick up your sleeve?

It sounds like a fried ABS/ECU.. the code 7 is usually caused by that, but in quite a few cases, a long reset was successful in clearing it and the ECU worked fine. I haven't seen one that wouldn't at least temporarily reset (and then fault again when you move off..)

<b>You did have the center pin of the diagnotics port grounded whilst you were doing the reset right?</b> Not just pressing the ABS switch/button..

It won't reset without the pin being grounded..

If you didn't - please redo with the pin grounded and report back - I'd start out with the long-reset. Can't hurt - might work, and will work if any of the shorter resets would have worked.

Best,

toddthom
09-23-2003, 09:07 PM
yes, grounded and without the ohm meter in between.

toddthom
09-23-2003, 09:11 PM
ALso, I just found a used ABS ECU. Don't know if it's a 1 or 2 yet.. My dealer says I have an ABS 1 type system on the 1992 RTS - K75. I haven't pulled the computer to see what number is on it.