iABS problem, appreciate suggestions

[PETDOC]

I may be experiencing a failure of the iABS on my '04 1150 GS. I purchased the bike new and have done all maintenance and repairs during 48,000 miles of trips covering 44 of the States and Canada. Using funnel technique brakes were bled annually except for 2012 & 2013. Broke a few bones late 2011 and early 2012 so since November 2011 I've put less than 1,000 miles on the bike. It has always been stored in conditioned space, I changed out my brake lines for Speigler SS lines in 2010 and currently have a 2 1/2 year old Odyssey battery that is recharged using Odyssey charger every time voltmeter drops below 12.8V.

My problems began almost 1 year ago with the upper Brake Failure light (aka, ABS Warning light) coming on within 5 to 20 miles into a ride. The brakes worked fine and if I stopped the bike and restarted it the light never came on for the remainder of the trip. This happened on 3 separate rides. Less often during a ride the Brake Failure light began flashing at 4 Hz and the lower General Waning light (triangle) illuminated. When this happened the front brake worked fine but the rear brake had only residual braking. Stopping and restarting the bike has always solved the problem.

I checked the micro switches (both clicking) and front brake lever (not touching), pulled and cleaned the rear ABS sensor and changed the brake fluid in both the wheel and control circuits. Several days ago I went for a 70 mile ride. For the first 20 miles, which included several intentional sudden stops from both low and high speeds, everything worked fine. At the 20 mile mark the Brake Failure light came on, but brake function was normal; I could hear servo motor when I used either front or rear brake. After stopping the bike for about 30 seconds I turned on the ignition, the warning lights went through the proper sequence, I started the engine and as soon as I started rolling the Brake Failure light, which was flashing at 1 Hz went out. Rode 30 miles without incident then stopped for 45 minutes. Bike started fine, but within 5 miles the Brake Failure light was flashing at 4 Hz and the General Warning light was illuminated (no flashing). Again front brake was fine and rear had only residual function. I stopped and restarted. When I turned on the ignition the General Warning light went off, but the Brake Failure light never cycled to 1 Hz. When I started the engine the Brake Failure light continued to flash at 4 Hz, the General Warning light was not illuminated and I had only residual braking both front and rear. I assume this occurred because I started the engine with the Brake Failure light flashing at 4 Hz vs 1Hz. A short time later the General Warning light suddenly illuminated and once again the front brake worked fine, but rear was still only residual braking.
The following day the brake light sequence was normal on start-up

Looking at the codes:
1. Brake Failure (ABS warning) light ON, General Warning light OFF-- only residual braking in both circuits or ABS function has been deactivated.
Every time I had this situation both brakes worked fine and I could hear the servo pump when I activated either the front or rear brake. I assume my ABS was deactivated?? However, in each instance stopping and restarting the bike solved the issue.
2. Brake Failure (ABS warning) flashes at 4 Hz, General Warning light ON-- at least 1 brake circuit in residual braking function mode.
This would agree with what I experienced and it was my rear brake.
3. Brake Failure (ABS warning) flashes at 4 Hz, General Warning light OFF-- only residual braking available in both circuits. Self diagnosis not completed.
This happened when my Brake Failure light would not cycle down from 4Hz to 1Hz and I started the engine, but after a few minutes of riding the General Warning light came on and I once again had a normally functioning front brake.

I ran a GS911. It indicated 3 faults that were no longer present- low pressure in front and rear brakes and fault in front brake switch. I erased the codes and ran through all the other available tests for the ABS. Everything checked out. I then rechecked for faults and there were none recorded. I assume the recorded faults that were no longer present resulted when I had bled the brakes.

. I have a dash voltmeter which at rest is 12.81V, with ignition on it drops to 12.20V and when I hit the starter it momentarily drops to 10.96V. I spoke with a mechanic who told me if the voltage drops below 12.6 the ABS will not initiate; however, it doesn't seem like it could be a battery issue because the faults all develop several miles into a ride and the voltmeter is always in the mid 13V range when the engine is running.

Based on reading many posts regarding iABS failures my current plans are to:
1. Replace battery with Panasonic LCX 1220P. Had one for years and was very, very happy with it's performance.
2. Remove aftermarket rear LED brake/running light. Brake light test with GS911 was normal
3. Remove rear brake lever, clean micro switch and detach, clean and reattach electrical connector. GS911 test indicated switches were good.
4. Replace rear brake pads. Inner rear pad has 2.4 mm left, which is still considered good ( normal > 1 mm), but I'll try anything right now.
4. Check the rear ABS sensor gap.

Any other suggestions are appreciated

 

[20774]

I did a quick google site search for "iABS" and got the following that might be worthwhile reading to see if anything applies:

http://forums.bmwmoa.org/showthread.php?73928-iABS-Phantom-Activation-of-Brake-Light-and-Servo

http://forums.bmwmoa.org/showthread.php?71978-2003-R1150RT-Rear-I-Abs-out-and-Flashing-Lights

Good luck...

 

[PETDOC]

Thanks for links. The second one had a success story by identifying crimped brake switch wire. I'll add inspecting the entire length of the brake wire to my list.

 

[ragtoplvr]

no way would I replace a good odyssey with the Panasonic. I had one of them, it only lasted a year, and it had no cranking power. got to where it would not start below 40. Interestingly, it NEVER caused an ABS fault. The low voltage thing is from the older ABS system, the one you have is not pickey about voltage. Make sure some tire changer did not bend any of the vanes in the front wheel sensor, they are very easy to damage, trust me. I suspect the internal construction was changed at some time, or maybe I had a bad one. The odyssey cranks faster in the winter than the Panasonic did in the summer.

Rod

 

[PETDOC]

Ragtoplvr,
Sorry to hear about your bad experience with the Panasonic. I had replaced my OEM Exide gel battery with a Panasonic LC-X 1220P, which I kept hooked to a Battery Tender Plus charger when not riding. I enjoyed several years of excellent performance with the battery. I never experienced low voltage starting (have digital voltmeter mounted on dash) except for problem with OEM Valeo starter. I was seduced by the low weight of the new Shoari lithium battery and swapped the Panasonic for one. It was a huge mistake. Fortunately I was able to find a buyer for my nearly new Shorai battery and charger who lived in Southern Calif., a warm climate much more suited for lithium batteries.

 

[DougRaymond]

Following this with interest.
When the GEN or ABS lights come on during a ride, is that in response to your braking or just out of the blue?

It sounds like your ABS module repeats the initialization sequence at random times, hinting that power or ground wires have intermittent connection. The most likely suspect would be the green wire from keyswitch to pin 3 of the ABS module. I think there is some history of wires in the area of the keyswitch getting chafed. A wiggle test there might be useful.

Intermittent wires in the harness are suspect if the rear sub-frame has been hinged up several times, for clutch or trans work. Unfortunately wires in the harness are very hard to check as the harness is almost completely inaccessible under the battery box. Alternatively you can pull the ABS connector at the module and check each wire for continuity or shorts, while wiggle testing harness and connectors as much as possible. But if the problem is very intermittent you may not get useful info.
Note that the brake lever microswitches are Normally Closed Contacts so these circuits should show continuity end-to-end.
You need a good schematic for the tests, there are some easy to find.

If either brake lever is "stuck a little bit ON" during initialization you would get the flashing warnings you sometimes list, but it sounds like you have carefully checked that neither switch is stuck.

 

[PETDOC]

Doug,
Thanks for the feedback. Having read posts regarding wiring breaks due to tightly zip tied harness near the ignition switch, I cut and replaced those zip ties long ago. I have replaced the clutch and slave cylinder twice, so the rear frame has been up twice.
Your question 'do the warning lights illuminate with braking' is an excellent one. I don't know the answer as I am typically well into a ride when I look down and see one or both warning lights on. Since the front brake is always working normally, I'm oblivious to any problem until I see the lights. The fact that the fault is not present with start-up and the GS911 interrogation of my ABS found virtually no problems gives me hope that it is an intermittent short somewhere and not a dying ABS module.
As you might imagine I've read many threads on iABS failures. Most reports of module failures that show the same warning light sequence as my bike with only residual rear braking have high rear wheel circuit pressure recorded by the GS911; mine was normal pressure in both front and rear wheel and control circuits. Again, fingers crossed, may not be a module failure.
Some of the things I'm doing now are only because others reported they fixed a similar problem in their bike; however, based on the GS911 results they really make little sense to me. Examples include replacing rear brake pads, replacing battery, re-flushing rear wheel circuit, restoring brake/running light to dual filament bulb, and topping off brake fluid in ABS module.
Because of the residual braking in the rear wheel and normal braking in the front I'm concentrating on the wiring from rear microswitch to brake light and ABS module. The rear microswitch has continuity.You have a point and I will pull the battery box if necessary. I already split the wrap on the wiring harness to the ABS module and inspected every wire for an abrasion/ break and made sure all pins were straight in the connector; so far all is good.
I contacted Module Masters and they indicated it would be another couple of months before they have the parts for a rebuild of the iABS unit. I'm on their contact list, which apparently now contains more than 100 people. I suggested someone should write a form letter to the NTSB and have all the people on the waiting list mail it in, still hoping, of course, I'm not one of them.
Dave

 

[cehlbeck]

Ragtoplvr,
Sorry to hear about your bad experience with the Panasonic. I had replaced my OEM Exide gel battery with a Panasonic LC-X 1220P, which I kept hooked to a Battery Tender Plus charger when not riding. I enjoyed several years of excellent performance with the battery. I never experienced low voltage starting (have digital voltmeter mounted on dash) except for problem with OEM Valeo starter. I was seduced by the low weight of the new Shoari lithium battery and swapped the Panasonic for one. It was a huge mistake. Fortunately I was able to find a buyer for my nearly new Shorai battery and charger who lived in Southern Calif., a warm climate much more suited for lithium batteries.

I got over 4 years of service and about 33,000 miles out of the Panasonic on my K1200LT. And I too put it on a battery tender whenever not being ridden, even if putting her away and knowing I would be riding the next day. On the road, I didn't put it on a tender. But, I have just replaced it with an Odyssey and right away, I noticed more robust starting than the Panasonic ever did.

 

[BC1100S]

I was seduced by the low weight of the new Shoari lithium battery and swapped the Panasonic for one. It was a huge mistake. Fortunately I was able to find a buyer for my nearly new Shorai battery and charger who lived in Southern Calif., a warm climate much more suited for lithium batteries.

Interesting. A buddy I ride with has a Shorai in his R1100S and it fired right up on a 0 degree Celcius morning in Lakeview OR late last fall. Me, I have a Panasonic. I guess we're both rebels.

Sorry for continuing this thread derail.

 

[PETDOC]

I've had some second thoughts on my early explanation for and dismissal of faults the GS 911 reported. They were reported as no longer present and I assumed they were caused by the recent brake bleed. I'm still convinced the low pressure in the front and rear wheel circuits were brake bleed associated, as the ignition is on when I bleed the wheel circuits. The front brake switch fault may have merit.
My logic is as follows:
1. Detectable malfunction has been in rear brake-residual braking only.
2. Fault appears well into ride and clears with restarting the bike.
3. My brakes are partially integrated; therefore, the front brake also activates the rear.
My conclusion being I need to really inspect the front brake switch and wiring. If the switch intermittently fails it could set off the warning lights at random times when braking, but the fault would be inactive once the ignition is stopped and restarted.

 

[PAS]

There have been several owners that have eliminated the iABS servo system. When mine starts to act up it will be history! I just downloaded the procedure this morning.
03 R1150RT

 

[PETDOC]

I have:
1) replaced what I believe to be a perfectly good 2.5 yo Odyssey with a new Panasonic battery
2) re-torque rear wheel bolts, cleaned and checked gap on rear ABS sensor
3) cleaned and checked gap on front ABS sensor
4) replaced what I believe to be perfectly good front and rear microswitches with new switches and cleaned the connections with electrical contact cleaner. Continuity with old and new switches tested same with multimeter.
5) cleaned the connections on the ABS sensors with electrical contact cleaner
6) split the wiring harness for the ABS module from above to below the battery box and examined every wire with a magnifying glass-no observed abnormalities
7) topped up already full, recently flushed wheel circuits with DOT4
8) replaced the rear LED brake/running light with OEM dual filament bulb

The only possible abnormality I detected during my examination of various wires was the connection for the rear ABS sensor under the right side of the rear of the front seat wasn't completely seated; it moved about 1/8 to 1/4" when I pushed it together. I did purchase some new rear brake pads but elected not to replace the old ones at this point. My plan is to go for a ride and if the warning lights reappear, which I believe they will do, take it to the BMW dealer and see if the BMW tester can definitively confirm that it is the ABS module. If that is the case I'll just wait until Module Masters has acquired the parts to rebuilt it. When working I love the servo ABS brakes. They have allowed me to enjoy 48,000 miles of memorable rides throughout the US and into Canada, so eliminating the ABS is not an option that I would consider.

 

[PETDOC]

Guardedly optimistic!
Just returned from a 62 mile ride. Brakes worked fine and no warning lights appeared. Although this problem has been intermittent, during the 3 rides prior to this one the warning lights routinely illuminated within 5 to 30 minutes of beginning a trip.
If the problem is resolved I don't know what I did that fixed it. I reviewed many threads on malfunctioning iABS units and in one a poster insisted most problems are related to one of the microswitches. Perhaps replacing them and cleaning connections cleared the problem. Based on continuity testing the old and new microswitches were not distinguishable, all tested at 0.5 ohms. It could have been a bad connection or an intermittently failing microswitch. The borderline incomplete attachment of the rear ABS sensor connector could have been the problem.
My present plan is to put a couple hundred more miles on the bike before exhaling. If after that all is well I will replace the OEM brake/running light bulb with the aftermarket LED.

 

[ItsPhilD]

I loved my servo-ABS on my 2004 R1150R. Best brakes I ever had. Never had a problem, sold it with 56,xxx.

 

[PETDOC]

Enhanced optimism.
Another 62 mile ride with normal brake function and no illuminated warning lights. I'm very suspicious that the incompletely seated electrical connector for the rear ABS sensor may have been the problem. I'm assuming a random bump during a ride would have transiently interrupted the signal from the rear ABS sensor triggering the warning light and loss of rear brake servo/ABS function. This possibly could also explain the fault disappearing when the motorcycle was stopped and restarted.
I appreciate the input by others and will not post any more updates unless the problem recurs.

 

[PETDOC]

Damn. Thought I had solved my iABS problem but it has resurfaced. On a 60 mile ride the lower triangle illuminated (steady) first followed a few minutes later by the Brake Failure light cycling at 1 Hz. Honestly I can't detect a problem with the brakes. With 100% certainty the front brake works perfectly in every way. Perhaps the rear brake is functioning in Residual capacity, but I can't tell. When I turned off the ignition, as before, everything appears to reset for a while. After doing about 50 miles I stopped for lunch. When I started the final 10 miles everything was fine. I found a steep hill, stopped facing down, locked up the rear brake, sat there for a few minutes and listened to the servo kick on and off like it always has since the bike was new. I went a short distance and did this again hoping if a valve is sticking in the servo it may loosen up. The ride home was uneventful. If the problem resurfaces, and I believe it will, I'll do the hill test when the warning lights are illuminated to see if I can hear the servo.
I may finally resort to going to the local BMW shop and see if their diagnostic tool can identify the problem. I fear they will say you need a new servo unit.

 

[mneblett]

I found a steep hill, stopped facing down, locked up the rear brake, sat there for a few minutes and listened to the servo kick on and off like it always has since the bike was new. I went a short distance and did this again hoping if a valve is sticking in the servo it may loosen up. The ride home was uneventful. If the problem resurfaces, and I believe it will, I'll do the hill test when the warning lights are illuminated to see if I can hear the servo.
I may finally resort to going to the local BMW shop and see if their diagnostic tool can identify the problem. I fear they will say you need a new servo unit.

I fear that your problem is failure of the piezo pressure sensors in the pump chambers, not the valves. These are the parts that Module Masters has been trying to source for years, so no easy fix is available yet.

 

[cele0001]

Its the sensors, its the valves, its the pump.
Whole system is heavily proprietary and most of the components have been designed and built specifically for the unit, and found nowhere else.
I suspect in 10 years time there will very few of these bikes with iABS still working.
One thing you should not be concerned with while riding is the brake. Anybody that experienced residual braking on these machines knows that if something goes wrong at the right moment, consequences would be severe.
I have no problem with ABS but fail-safe mode should still leave you with "regular" brakes.
"Intermittent brake" is not something I want to troubleshoot. Take it out and move on. Hydraulic works.

 

[PETDOC]

What, if any, are legal implications of removing the ABS unit? Can I sell the bike to someone without incurring liability for disabling the ABS?

 

[Jeff488]

What, if any, are legal implications of removing the ABS unit? Can I sell the bike to someone without incurring liability for disabling the ABS?

The fact that in this country any one can sue anyone for anything at any time notwithstanding, if the bike is sold as a non-abs unit, then no
legal ramifications should ensue.
Placing the non-abs condition in the bill of sale would be a good idea.

Just my opinion and worth about what you paid for it.