BMW Luxury Touring Community banner

1 - 20 of 115 Posts

·
Registered
Joined
·
69 Posts
Discussion Starter #1
I have just carried out a reset of my ABS 2 :dance:

This is for 99/2000 model LTs.

It is not for models with integral ABS.

It has been suggested that the only way to clear ABS2 faults is by placing it on the diagnostic computer at a dealers shop.

I have just proved that this is not true. It can be done at home relatively simply.

What I am describing clears the memory of faults and returns the abs warning lights to normal on startup. If however you have failed to cure the cause of the fault, eg bad wheel sensor, the warning lights will return to their warning state once the bike has gone through it's self test process.

Firstly you can do some investigation of your own fault codes.

Under the front seat and clipped to the frame there is a diagnostic connector. It is cylindrical in shape and has a removable push-and-turn grey cap.

Remove the cap and locate the pin 2 - connected to a brown/blue wire. Connect an analogue meter between pin 2 and earth. Turn on the ignition. The meter will initially settle at around 10V. It's what happens next that is of interest. The needle will fall to a number of lower voltages in a series of pulses. Count the number of needle drops. This number is your fault code.

The following codes have appeared on other forums. I cannot guarantee their accuracy but they may point you in the right direction:-

1.Front pressure modulator.
2. Rear pressure modulator
3. Front wheel speed sensor
4. rear wheel speed sensor
5 battery voltage too low
6.ABS relay
7.ABS control unit
8. sensor gap front or rear or other outside influence.
9. Unknown .....
16. Failed plunger test


Ok. This may help you cure the actual fault which is causing the alternating (wigwag)warning lights.

To carry out a reset, this is what I did. You need to get to pin 21 on the ABS controller. The connector is plugged into the abs unit which can be seen next to the battery holder towards the left hand side under the seat.

I removed the battery to create some space.

Now this is where it became challenging. I didn't want to remove the whole unit just to release the connector.

As you look down from above you can see a protruding rectangular steel clip at the bottom of the connector. You need to push this down whilst you prise out the connector from the bottom. No easy feat but I managed. Unfortunately, the connector continues to be held in at the top of the unit. The connector itself has a plastic lip which hooks under the top of the abs unit. You will see a small screw in the top of the connector. Do not remove this - it will not help - it has nothing to do with release.
Lack of space meant that I could not revolve the connector sufficiently to release the lip. After much knuckle bleeding I used half a junior hacksaw blade to saw the piece of plastic from the connector. This allowed it to come free. On final replacement I will tie wrap the connector back in place for security.

I then had to dismantle the connector to reveal the wire locations. I had to roll back the rubber protector tube where the wires enter the connector. This reveals two screws. There is another screw at the top of the connector. Remove all three screws and then pull the connector block from its housing so you can see where the wires enter the terminal holes.

The inner connector has its terminals numbered along the sides. Terminal 21 is vacant. I stripped a thin wire and threaded it through the hole and then bent a small amount over to hold it in place being carefull not to interfere with other terminals.

I then carefully replaced the connector onto the ABS unit and replaced the battery.

OK. The reset. I earthed pin 2 of the diagnostic connector and kept it earthed.

I then switched on the ignition. Both ABS lights were flashing alternately. I then grounded the wire from pin 21 and made a count of 8 seconds. As soon as I grounded this wire one abs light stayed on and one went off (can't remember which one). At the count of eight I removed the pin 21 wire from earth. This results in both abs lights staying on together.

I switched off the ignition and removed the diagnostic earth wire.

When I switched the ignition back on, both abs lghts were flashing simultaneously. Just as they should. :D

I'm going to leave the pin 21 wire in place so that I can reset in the future at will.

Hope this proves helpfull to you all.

Merry Christmas

Chris
 

·
Registered
Joined
·
3,525 Posts
Nice work Chris,

How did you come by this information ?


John
 

·
Registered
Joined
·
69 Posts
Discussion Starter #3
JPSpen said:
Nice work Chris,

How did you come by this information ?


John
Hi John. Simply hours of searching and trawling the net.

I was a little anxious that I might damage the unit in some way but as it wasn't working anyway I felt I had nothing to lose. Hey presto - it worked. Tremendous feeling of satisfaction and well worth the effort.

Regards

Chris
 

·
Wrencher Extraordinaire
2005 K1200LT
Joined
·
14,138 Posts
Well Done Chris,


That is the type of persistance and daring that makes being a part of this site so fantastic. You have earned a spot in the maintenance hall of fame!! Now if there were an easier way to get that connector off...
 

·
Premium Member
Joined
·
1,882 Posts
When you say it works, are you saying the lights no longer flash or you have taken it down the road and jammed on the rear on gravel to see if the ABS kicks in?
If the latter, I will report back shortly, as mine is in bits, so I may as well go for it.
 

·
Registered
Joined
·
69 Posts
Discussion Starter #6
c00k1e said:
When you say it works, are you saying the lights no longer flash or you have taken it down the road and jammed on the rear on gravel to see if the ABS kicks in?
If the latter, I will report back shortly, as mine is in bits, so I may as well go for it.
Hi Cookie

The procedure I decribed clears any record of fault from the electronic memory.

It cannot and will not repair a physical fault on the bike. If you have a faulty wheel sensor or other abs component and you do not correct this the lights will return to warning mode following self-test and the abs function is automatically disabled.

Do the fault code analysis, address the route cause of the problem and then do the reset. Then your system will function correctly.

If the analysis points to a faulty unit (the really expensive bit), it has been reported that a full system flush can sometimes restore normal operation.

The breakthrough here is that you don't have to visit the dealer everytime you want to reset your lights.

Have a go - you've little to lose - good luck.

Regards

Chris
 

·
Registered
Joined
·
4,404 Posts
Excellent post

As a DIYer I am very happy to have this procedure available.
I printed it out and will put it with my shop manual.

Your procedure does belong in the Hall of Wisdom.

I did purchase the GS911 code reader tool, but I understand it will not reset ABS faults on the 99-2000 models. Your method of resetting the ABS fills the gap.

Good work and thanks!
 

·
Premium Member
Joined
·
3,113 Posts
BDC said:
Thanks Charlie. It's good to get some positive feedback.

Chris
You really brought some very valuable information to this forum.

I hope as I learn, that I may also contribute a little for all that I receive from this forum.

Great work on your part :bmw:
 

·
Registered
Joined
·
12,165 Posts
Great work!

This is really good information for the HOW.

Grounding a pin for a set time period is how BMW does resets for warning and service intervals on their cars also. It is relatively easy to reset the "Service Engine", "Service Interval" and "Oil Service" lights on the cars, so it probably would have been expected on the bikes also. It just takes someone like yourself that will expend the time and effort to uncover the procedure. The difficulty is normally finding out not only which pin, but the time period to keep the pin grounded. On the cars the time periods are different for the individual items to reset.

Thanks for your work!
 

·
Registered
Joined
·
69 Posts
Discussion Starter #11
Thanks David

I, like many others on this board, value your own wealth of knowledge and practical experience.

My research indicated that getting the reset sequence correct is critical. Also ensuring good connections to earth.

If I had more time I would create a series of faults eg disconnect a wheel sensor, and then verify the fault codes. Perhaps in the future.

Chris
 

·
Registered
Joined
·
69 Posts
Discussion Starter #12
LAF said:
You really brought some very valuable information to this forum.

I hope as I learn, that I may also contribute a little for all that I receive from this forum.

Great work on your part :bmw:
Thanks LAF, that's a great philosophy for this board. If it's good - share it.

Chris
 

·
Registered
Joined
·
76 Posts
Adding some more info. Yes It does work!

1. I used a fine toothed sabre saw blade and gloves to cut the top black plastic "catch" on the connector. 10 min work, a dremel tool might work too.

2. Which connector is 21? There are 2 vertical rows (left and right) of male spade connectors on the ABS control unit. Pin 21 is the 5th one down on the left row. I used 1/2 of a mini female spade connector to get a more positive connection.

3. I bought a 12v LED from Radio Shack to get a readout of the diagnostic code(s), off terminal 2. It would not flash, BUT the idea of a analog voltmeter needle bouncing does work. :) I first got # 7 (the control unit itself). Grounded both terminals 21 and 2 and the lights stopped flashing! I have the FD off and got another code #9 at the next ignition turn on. I've got to wait until everything is back on, to further test. (Working on the ABS, Aux. Lights quit working, drilling clutch slave weep hole, bad pivot bearings, reverse not working (See seperate posting for fix) and front tranny input shaft seal leak :( )
 

·
Registered
Joined
·
69 Posts
Discussion Starter #14
suzbmwhnd said:
1. I used a fine toothed sabre saw blade and gloves to cut the top black plastic "catch" on the connector. 10 min work, a dremel tool might work too.

2. Which connector is 21? There are 2 vertical rows (front and back) of male spade connectors on the ABS control unit. Pin 21 is the 5th one down on the back row. I used 1/2 of a mini female spade connector to get a more positive connection.

3. I bought a 12v LED from Radio Shack to get a readout of the diagnostic code(s), off terminal 2. It would not flash, BUT the idea of a analog voltmeter needle bouncing does work. :) I first got # 7 (the control unit itself). Grounded both terminals 21 and 2 and the lights stopped flashing! I have the FD off and got another code #9 at the next ignition turn on. I've got to wait until everything is back on, to further test. (Working on the ABS, Aux. Lights quit working, drilling clutch slave weep hole, bad pivot bearings and front tranny input shaft seal leak :( )
Fantastic. I like your idea of half a female connector to obtain a better connection. I'll use that myself when I make my final re-assembly.

I'm pleased the reset worked for you. :) It proves my work was not a chance occurence and that my description was helpful.

Good luck with your other problems.

Chris
 

·
Registered
Joined
·
148 Posts
Well done BDC.
You must have put a lot of time researching into this “fix it”.
So many DIY’s are going to benefit from this post
Thank you for shearing with us all.
My ABS works fine for now. But you never know when your going to need info!
I take my helmet off to you
 

·
Registered
Joined
·
69 Posts
Discussion Starter #16
Bear-KLT said:
Well done BDC.
You must have put a lot of time researching into this “fix it”.
So many DIY’s are going to benefit from this post
Thank you for shearing with us all.
My ABS works fine for now. But you never know when your going to need info!
I take my helmet off to you
Thanks Bear

I'm glad your abs is working. A major ABS failure can be very expensive to repair. My advice would be - dont leave anything to chance. Do the annual brake fluid change. It's a simple diy task (a bit time consuming) and costs peanuts.

Regards - Chris
 

·
Registered
Joined
·
143 Posts
I don't know if this will work or not, but the attached pdf contains a description and circuit diagram of an LED display that was used for first gen K bikes (K75's and K100's) to display ABS fault codes. I lifted this from www.ibmwr.org's tech section.
 

Attachments

·
Registered
Joined
·
552 Posts
Chris, I think if you cleaned this up with more of what you learn and took a few pictures this would be a great item for the Halls of Wisdom.

Great Job. Thank you for sharing.
Tom
 

·
Registered
Joined
·
564 Posts
Maybe if BDC is willing to share this info with the GS911 folks, they could build it into their next update.
 

·
Registered
Joined
·
2 Posts
Chris;
Many thanks I followed your instructions regarding abs faults and reset on a 99 1200lt and found fault 3 front abs sensor. This I had just replaced because it would not register any pulses on oscilloscope, however I had no way to clear fault and reset abs without your help. I removed the abs controller wiring connector more easily by removing the +pos cable post junction located behind abs connector . This allowed enough room to release the top lip. I also found that bosch fuel injector connectors off a 2002 Kia Sportage just happened to have same wiring connectors as the bmw abs controller. (small world!!) so I was able to just run new wire to #21 terminal just like factory and leave for future reset. Bike self tested and abs lights went out on rollout . Dealer wanted to replace abs controller for approx 3k so my customer is very happy!!!! Again many thanks. Wrenchall
 
1 - 20 of 115 Posts
Top