Defects in anti-lock braking systems

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Defects in anti-lock braking systems
BMW

motorcycles

Defects in anti-lock braking systems

Defects in anti-lock braking systems
Failure symptoms

ABS is the most important, oldest and most common safety feature of modern motorcycles. But defects in ABS control units can be unsettling: They are counterproductive, complicated and expensive to repair. It hits BMW particularly often, often caused by Cent components.

Thomas Schmieder

08/31/2017

An article that only aims at problems without paying tribute to the millions of vehicles that work correctly is a bit one-sided, ”wrote Uwe Dorner when he called on MOTORRAD readers to tell us about defects in ABS devices. From 2003 to 2016 he drove 55,000 kilometers without problems on a BMW R 1150 GS. Like many other ABS machine drivers. Well, there is no doubt about the enormous importance of anti-lock braking systems on motorcycles, they prevent accidents and leave bones whole.

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Failure symptoms

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In 2016, however, reader Marc Sille experienced a moment of shock on his 2007 BMW R 1200 GS: “Suddenly the ABS failed after only 13,800 kilometers, in urban areas when there was an emergency braking. I felt the rear wheel lock up, only then saw the ABS warning light. ”Marc Sille knew motorcycles without ABS, released the brakes and was able to swerve. “After all, the braking force was fully available, only the ABS and integral function with transmission from the hand lever to the rear wheel suddenly failed. Nevertheless, this situation could have ended differently, since you rely on ABS. ”Marc Sille had previously had an ABS defect on his BMW K 1200 S, also from 2007. Without the ABS function, it will be annoying and expensive. At the TuV, the motorcycle does not pass the general inspection according to § 29. ABS that is no longer working is indicated by control lamp (s) in the cockpit, with various flashing frequencies depending on the type of malfunction. This is mandatory. Like our readers, BMW dealers and independent service companies also report frequent problems at BMW. There are many reasons for this: The German ABS pioneer installed the most important safety technology as early as 1988. Such K models with “ABS I” are now almost old-timers, spare parts for their ABS are no longer available. In addition, the Bavarians were encouragingly to rely on a high ABS quota: from the year 2000, the F 650 GS was for a long time the only mid-range motorcycle with ABS!

BMW has not sold a new model without ABS since 2013. In spite of this, or precisely because of this, some of the sometimes very complex BMW control systems show typical error patterns after years. The basic principle of ABS is always the same: sensors on the wheels, usually rims with 100 or 120 signals per revolution, measure the current wheel speed. If this drops too much when braking compared to the other wheel, there is a risk of locking. The control electronics now regulate the brake pressure on the brake calliper via valves, pistons and pumps so that the wheel continues to turn and can still take over cornering forces.

With the “ABS II” from 1992, BMW’s suppliers began to combine the electronic control unit, including the pressure modulator for the front and rear wheels, in a centrally placed hydro block or hydraulic unit: the ABS control electronics and pumps driven by electric motor (s) sit in just one housing. In the system with a brake booster, two pumps build up to 120 bar brake pressure on the brake calipers; in modern devices, the electric motor maintains counter pressure on the brake lever. This is why today’s ABS no longer pulsates when the brakes are applied hard. But often the electric motors cause problems. Especially in the BMW Integral ABS II from Continental Teves from 2006 collectors wear out, the brush motor brushes wear out.

Furthermore, carbon abrasion can accumulate and in extreme cases cause a blockage, a short circuit or a burned-out transistor output stage in the control unit, ”says Rainer Hutterer, head of ABS specialist RH Electronics, who repairs 90 percent of BMW components. “The windings of the electric motors are made of pure copper and can oxidize with oxygen and water.” Just like electronic circuit boards, the carbons are not intended for replacement, the cup-shaped cover of the electric motor is firmly caulked with the hydro block. If the brushes are worn out, the entire hydro block has to be changed: Cent-articles put high-tech out of action. With Marc Silles 12er-GS, the error message stored in the memory was “Power supply pump motor (code 5DF0 and 5DF1)”. Not an isolated case. Even BMW admits.

A new part including wages costs over 1500 euros, depending on the workshop. When it comes to repairs, specialists step into the breach: They professionally open the devices with CNC machines, repair and overhaul the affected assembly and sometimes re-seal the electronics. This costs from around 300 euros, plus shipping, installation and removal. “It’s like an open heart operation, only for absolute specialists,” says Felix von Sparr from the Reitwagen Motorrad Hamburg workshop.

Rainer Hutterer: “In BMW’s Integral ABS I with electrohydraulic brake booster, there are six bleeder valves on the hydro block alone that are difficult to access under the tank. If this is not done carefully, old brake fluid will always remain in the system. It is hygroscopic and binds water from the ambient air. ”This can cause rust, which damages the sensitive hydraulic pumps made of ceramic and metal:“ They only have a few micrometers of play and they set quickly. Old brake fluid that crystallizes out has a similarly damaging effect. ”Yamaha dealer Dominik Klein warns against do-it-yourself when changing brake fluid:“ Only special plugs and diagnostic testers simulate the ABS control unit’s control range – only then do all pistons and valves work and pump the old brake fluid completely out. ”Therefore, regular brake fluid changes in certified contract workshops according to factory specifications are essential to extend the service life of the hydraulic units. Even if there is no one hundred percent guarantee against damage.

Regular use of the ABS is just as important! This helps to keep pistons and valves moving and prevents rot. It is not uncommon for defects to occur in the most complex braking system, the BMW Integral ABS I from FTE, which has been installed almost 315,000 times since 2001, after the winter break. Here, two pumps and motors sit in a housing milled from solid. Spare parts price only: around 1700 euros. Makes up to 2500 euros including installation and removal. With a 15-year-old R 1150 that is almost the current value. RH Electronics repairs these sensitive devices almost exclusively, for around 950 euros including a two-year guarantee. In addition, there are the costs of the home workshop.

Rainer Hutterer: “I consider the measuring surface of the ceramic pressure sensors with a diameter of four millimeters to be too small for the pressures that occur.” This stresses and damages the measuring bridges behind it: “Pressure is force per surface.” !) built in O-rings and seals. “If brake fluid then escapes, it can destroy the electronics on the sensor.” In the event of an electrical, hydraulic or mechanical malfunction, the servo system switches to the residual braking function via bypass valves: the front and rear wheels are then decoupled and braking is now required a longer lever path with much more effort. “In the middle of a motorway in France, the ABS warning lights on my 2006 BMW R 1150 GS suddenly started flashing very quickly,” reports reader Thomas Hellmann. “It feels like 90 percent of the braking power has been lost.”

Thomas Hellmann now had to pull the lever like an ox. One thing is clear: the brake booster suddenly got out. Its two non-wear-free electric motors for the front and rear wheel brake circuit can otherwise be heard hum with the ignition switched on every time the brake lever / pedal is pressed.

ABS defects in Japanese machines are less common, but when they occur they are even more expensive. For the Yamaha FZ6, the hydro block costs around 1,600 euros, for an FJR 1,300 even 2,700 euros, plus installation and removal. Expensive failure symptoms. Nevertheless, if you need ABS once, it has paid off.

Interview: “Pressure sensors and carbon brushes can fail.”

Gerhard Lindner. The BMW press officer takes a position after consulting the engineers.

To the best of BMW Motorrad’s knowledge, if certain ABS brake systems are sometimes defective?

We are not notified of any defects in most ABS systems. The need for spare parts for first-generation Integral ABS (FTE) is due to pressure sensors that, with increasing age, run out of the prescribed tolerance window. If this is the case, the system reverts to the residual braking function without a brake booster. Even in this state, the brake still achieves the braking values ​​prescribed by law. (Editor’s note: 5.8 m / s² when both brakes are actuated, 4.4 m / s² with the front brake alone.) However, such defects are detected very early in the course of maintenance work. With the second generation integral ABS (Continental Teves), there were defective carbon brushes in the electric motor in some parts of the first months of production.

Are some ABS systems at BMW Motorrad more often damaged than others – keyword brake booster??

Apart from the findings mentioned at the beginning, the maintenance status is decisive. So there are no system-specific abnormalities here.

Can parameters such as the age of the motorcycle, mileage, frequency of the brake fluid change and regular or infrequent reaching of the ABS control range influence the frequency of damage?

Provided that BMW Motorrad’s maintenance specifications are complied with, we are not aware of any conditions that would limit the service life. Every technical system is only as good as its maintenance status! To ensure that the anti-lock braking systems are always in an optimal condition, we urgently recommend that you adhere to the prescribed inspection and maintenance intervals.

Why is it extremely expensive to replace and repair the hydraulic units in models with a brake booster??

BMW Motorrad introduced the 1st generation system with brake booster back in 2001 and was a pioneer in two-wheel ABS. Because of the small number of items that this entails, manufacturing costs are high. Over the entire production period of nine years up to 2010, a total of 314 575 motorcycles with brake boosters were built and sold worldwide. The long construction time is due to the fact that we continued to build one or the other (non-volume) model until the series was discontinued. The majority of the systems were only installed until the introduction of the Conti system in 2006. At the moment, only very few components are still being manufactured for spare parts, a fact that inevitably leads to high manufacturing costs.

What advice do you give to drivers who have problems with ABS control units / hydraulic units, especially if the motorcycles are between 10 and 15 years old?

We recommend customers who discover a problem with the ABS system to have it checked by their BMW Motorrad retailer. Because the necessary diagnostic systems and competence are available there. There it can also be checked to what extent the vehicle can possibly be repaired as part of the goodwill.

Interview: “Noticeably susceptible: Integral ABS I”

Rainer Hutterer, 45, is a master information electronics engineer and founder of RH Electronics. His company repairs thousands of ABS control units for customers around the world every year – for BMW and Japanese.

What kind of ABS damage actually occurs?

Many come into consideration, damage can be electronic or electrical, hydraulic or mechanical. In every motor vehicle there are large temperature fluctuations, condensation and, in the case of motorcycles, also strong vibrations. Defects on electronic boards are mostly due to soldering errors, oxidation or kinked pins – the plug contacts are sensitive to bending. Fine ball seat valves are located in hydro blocks. Like the ABS pistons, this filigree mechanism can corrode – especially if there is water in the brake fluid. In general, water damage plays a central role: in the BMW K 1200 S and R, for example, the device is located in the splash water area of ​​the rear wheel, but is not optimally sealed. This of course promotes corrosion and potential short circuits.

Why can’t affected drivers simply install used control units??

When it comes to used equipment, you buy a pig in a poke, you don’t know the origin or history. Does the purchased device really fit in my motorcycle? Is his software compatible? The devices must be coded on the vehicle. Cheap on Ebay doesn’t help if you don’t know whether it works or if you have problems again after two months. Sporadic errors that only occur now and then are particularly annoying. 

Equip the often defective electric motors with maintenance-free components?

No, we optimize with higher quality, up-to-date components as far as possible. But we are not allowed to convert the devices: This would be a technical change and would have to be approved by the KBA (operating permit). We expect an additional service life of six to eight years for electric motors that we have overhauled.

How much do repairs cost at RH Electronics?

Depending on the ABS system, the defect and the effort involved in checking the repaired device, usually 300 to 850 euros, plus shipping and installation / removal. All in all, this is a repair that is fair value. If the ABS control module can no longer be repaired, we still have around 400 refurbished exchange devices in stock, sorted by type series. FTE’s complex Integral ABS I with electrohydraulic brake booster (BKV) is particularly susceptible: some customers have already had their second or third repair, despite a two-year guarantee on replaced components. That is why we are now offering a three kilogram lighter “Plug & Play “conversion kit for conventional brake actuation without integral function, ABS and BKV. It can be entered in individual acceptance.

Problems in Real Life: Excerpts from the many reader experiences

We received letters from readers about 141 ABS failures, with a mileage of 800 to 392,000 kilometers, an average of around 49,000. Among them were 121 BMWs, or 85 percent. ABS failure plagued 39 drivers of a R 1200 GS with initial registration from 2006 to 2008 (Conti Teves system). On the other hand, nobody described defects in BMW’s F models (650s singles, 800s twins). All defective boxers and three / four-cylinder K types were approved until 2010. Younger people are therefore more reliable or not old enough for defects. The 20 other machines with ABS problems (including younger ones!) Are from Aprilia (one failure), Honda (six failures), Kawasaki (six), Suzuki (four) and Yamaha (three).

Water penetrated my 2006 Suzuki Bandit 1200 S. had the plugs of the ABS unit corrode after 24,000 kilometers in 2015: verdigris interrupted the flow of electricity. The cause was a defective seal between the wiring harness and the ABS unit. The failure of the ABS was indicated by an error message in the cockpit after the winter break. The repair with a used ABS control unit (120 euros used instead of 1500 euros new) cost around 500 euros, including the necessary refilling and bleeding of the entire brake system. Now the wiring harness would have to be replaced, as the seal to the control unit is not available separately. Bastian Riebesell

Bought my Kawasaki Versys 650 At the end of 2010 in Thailand. It has been checked and properly driven on long journeys (I am a graduate engineer in mechanical engineering). Brake fluids were always changed. Nevertheless, the ABS failed after 49,574 kilometers in 2016: The pedal was extremely stiff, the rear wheel locked when braking heavily. Tried unsuccessfully at the dealer to get the valves of the hydroblock going. So the device changed, for around 600 euros plus work. Heard from other drivers and mechanics that especially the rear wheel circuit of the Bosch ABS is very often affected and then breaks after three to four years. Torsten Schumann

BMW K 1200 R Sport, 39,000 kilometers, 8.5 years old: “Pressure modulator defective”. Replacement cost 1500 euros, the spare part alone 1280 euros. My brother and my friend both drive the K 1200 S and have the same problem. Seems to be a standard defect in the K series. According to the BMW dealer, RH Electronics repairs the pressure modulator for 415 euros plus installation / removal. Stefan Schirra

On my 2003 BMW R 1100 S. With Integral ABS I, the front brake circuit failed in 2013. The cause was brake fluid that had penetrated the control unit, which was not specially sealed. This happened to me myself when bleeding the six circles, the screws of which are right next to the electronics. The repair at RH Electronics cost 850 euros, including improvements in the electronics area. Since then, ABS has been working absolutely reliably and with significantly higher braking power than my second “S” without ABS. Winfried Riegert

For me, the frequent failure of ABS control units /Modulators at BMW obvious. For me, a K 100 RS with ABS I from 1989 (repair costs 2000 euros) and my R 1150 GS from 1999 have already been affected twice (repairs: once 1070 euros, once free of charge on a guarantee from RH Electronics). Joachim Breunig

I already had two defective ABS on my BMWs, first on an R 1150 GS bought in 2002, the damage occurred in 2008 after approx. 69,000 kilometers. The second defect was in 2016 in an R 1200 GS built in 2007, with a mileage of around 32,000. Norbert Reiser

In my BMW R 1150 GS, EZ 2003 with partial integral, the rear ABS and the brake booster failed after 392,000 kilometers. The controller was sent in to RH Electronics for overhaul by the dealer. Furthermore, the smoking cable harness had to be exchanged for a new one. Hannes Wienands

My ABS defect occurred 50 kilometers after changing the brake fluid in a BMW workshop on the R 1200 GS Adventure (EZ 2008, 82,000 km): “Pressure modulator voltage supply”. Wolfgang Baum

I have several K 1200 drivers in my circle of friends. Many have the ABS module problem. Like my K 1200 S after almost 22,000 kilometers. In all cases, the batteries were defective either shortly before or shortly after. I am an electronics technician. My suspicion is that the current will increase due to the battery voltage being too low and therefore the modules will be destroyed. Jan Stremme

The permanently burning warning light on my R 1200 GS (2008, 45,000 kilometers) was due to the defective pressure modulator. Error memory said: “Power supply pump motor”. Had an exchange carried out for 1424 euros, of which 1200 euros were for a new part. I am an industrial mechanic myself, dismantled the defective pressure modulator. Lo and behold: only a coal from the engine was stuck, the cage was simply too narrow. So bent up a little and it was good. Annoying to have to pay so much money for it. Bernd Conrad

With my BMW R 1100 S. with integral ABS, EZ 5/2002, 50,300 kilometers, ABS and brake booster failed downhill on Timmelsjoch without warning. Was not fast due to heavy rain, was only extremely surprised by the hardly any braking force left. So drove straight on at the roundabout. After this loss of confidence, I had the ABS expanded! TuV has approved it, it was entered in the papers in individual approval. Number 22 now reads: “ABS shut down. The vehicle was without ABS as standard, the pressure modulator deactivated. ”I now feel safer because such a failure can no longer occur. Christian Hanrieder

Advice and action: Tips and service addresses on the subject of ABS defects

Possible possible prevention of damage for drivers of ABS motorcycles

  • Change the brake fluid at least every two years, better annually for BMWs with brake booster (approx. 200 euros!). This must be done by certified service companies – with special tools / diagnostic testers for time-consuming venting.
  • Do not leave the vehicle standing for too long to avoid standing damage.
  • Brake several times a year into the ABS control range. The best way to do this is on an open, straight route (watch out for traffic behind you!), In parking lots or during safety training. For types with separate control loops, it is essential to activate ABS on the front and rear brakes.
  • In BMWs with a brake booster, a voltage drop in the on-board battery can lead to the ABS / BKV (“reset”) being withdrawn. Bear this in mind if the battery is low, downhill sections or during long training sessions.
  • It is better not to clean the motorcycle with high-pressure steam jets: Water that has seeped in can lead to corrosion and incorrect contact resistance.
  • If the ABS is defective, be sure to visit a brand workshop and submit a goodwill application there, even for older motorcycles. Only then contact (have) relevant specialists.
  • When installing a motorcycle battery, never reverse the poles! Voltage peaks that damage the ABS control unit can also occur when charging the on-board battery in the vehicle (with chargers that are too large for cars).
  • Never repair ABS hydraulic units and control units yourself!

Checkpoints for buyers of used motorcycles with anti-lock braking systems

  • Was the maintenance plan fully complied with? Have all the inspections been carried out by the due dates or mileage? Has the motorcycle in question been maintained in a service book, if possible by an authorized dealer?
  • Weighing up carefully: does it really have to be exactly this type of motorcycle? If the ABS is defective, BMWs with brake boosters and fully integral brake functions are particularly expensive and time-consuming to repair. Conversely, all F-models (!) As well as boxer and K-models from 2010 onwards cause much fewer problems, at least until today.
  • Be careful if ABS motorcycles are logged off for a longer period of time: damage to the stand could occur immediately after restarting.
  • Think outside the box: Probably the regularly serviced motorcycle with a higher mileage is less at risk of ABS defects than one with fewer kilometers but long downtimes.

ABS specialists and repair shops

  • RH Electronics, Control unit professional for over 25 years and market leader, renowned specialist for all ABS motorcycle types and brands, own workshop with express service; Telephone 0 81 45/99 76 50, www.rhelectronics.de
  • Glaubitz GmbH / ECU Zittau, repair instrument clusters (cockpits) of various BMW types and some ABS control modules, phone 0 35 83/55 47 80, www.ecu.de
  • ABS control units, specialized in BMW Integral-ABS II MK 60/61 from 2006 (Conti), repairs including improved guides for the carbon pencils: around 299 euros, phone 01 62/44 736 31 (Laatzen / Hannover),www.abs-steuergeraete.de
  • ACtronics GmbH, Subsidiaries in eight European countries, only delivers to workshops and dealers, phone 0 59 24/78 34 99, www.actronics.eu/de
  • “The workshop”, Specialist for BMW motorcycles in 50739 Cologne, specializing in BMW Integral ABS II (Conti) including high-quality “bronze carbon”, repairs only when the complete motorcycle is delivered, www.motorrad-reparaturen.de

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