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Thread: ABS and ASC problem with newly acquired 07 R1200RT

  1. #1

    ABS and ASC problem with newly acquired 07 R1200RT

    I recently acquired a very clean 07 R1200RT from a good friend with 36,000 on the clock. The bike has been dealer maintained, garage kept, and looks almost new. I rode 250 miles home, and the bike performed perfectly. Yesterday, we did a 240 mile ride, and had a strange issue about half way through. Iíd appreciate any thoughts some of you more experienced BMW riders may have concerning what the problem may have been. This is what occurred:

    About 120 miles down the road doing about 60mph, the brake warning light came on. No big deal, even I know this means a failure of the ABS, but brakes will still work fine. About a minute later, the ASC caution light illuminated intermittently. About a minute after this the engine started losing power for a split second, and then would surge back to life. It felt like it became fuel starved for a second, and then back to normal very quickly. It probably did this 10 times before we stopped about 10 miles down the road. We were stopped at a light, and when the light turned green, and I went to go, the engine completely died. We pushed the bike off the side, took our helmets off and scratched our heads for about 15 minutes. When we re-started the bike, all faults cleared, and it ran flawlessly for 120 miles to our destination. Here are some questions I was hoping you all could help me with:

    The brake failure light and ASC light came on within a minute of each other. It does not seem to me these systems are interrelated. Am I right about this, or am I missing something here?

    I couldnít think how the engine cutting out could be related to either of the other two problems, but after sleeping on it, I had an idea. I assume the traction control works by sending a signal to the engine (reducing fuel) to stop the rear wheel from losing traction. Is it possible the malfunctioning ASC was sending that signal to reduce fuel, and making it feel like the engine cut out?

    If I take the bike to a dealer, would the stored error codes possibly shed some light on what was going on?

    Iím happy all the faults cleared after restarting the bike, but my confidence level is a bit on the shaky side. We will be riding from Sarasota, FL back home to NE Florida in a few days, and would love to get a better idea of what happened before we make that ride. If any of you have seen similar problems, or have any insight into the issue, Iíd love to hear from you. Thanks in advance for your help.

    Happy Holidays,

    Steve
    07 RT

  2. #2
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    ABS & ACS failure.

    Steve, both systems rely on a signal from the rear wheel speed sensor. Sometimes a tight cable tie can cause a break in the rear sensor cable with an intermittent signal. Might be fine for awhile, then a bump can cause a failure. Sometimes the sensors can get a build up that can be wiped off the end. A single screw holds the sensor in place. A friend is on sensor #3 on his 2013 RT at 83,000 miles, other have gone many more miles with no failures. The dealer or someone with a GS911 can read and clear the codes. That sensor is used on quite a few models so easy to get a new or used part.
    Chuck Swenson
    MOA # 9162
    2010 R1200RT, 2003 F650cs (BMW #12 & 13)

  3. #3
    Chuck...thanks for the info. Iíll look into the sensor, and wait until the shop is open after Xmas to read the codes. Is it possible for this to cause the momentary loss of engine power as well?

    Steve

  4. #4
    Back in the saddle again mikegalbicka's Avatar
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    Haps Cycle in Sarasota has a good BMW mechanic who could help out.

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    Quote Originally Posted by sailorscd View Post
    Chuck...thanks for the info. Iíll look into the sensor, and wait until the shop is open after Xmas to read the codes. Is it possible for this to cause the momentary loss of engine power as well?

    Steve
    Yes if the ASC sees too many pulses it will cut fuel or retard spark to remedy what it thinks is rear wheel spin.
    Chuck Swenson
    MOA # 9162
    2010 R1200RT, 2003 F650cs (BMW #12 & 13)

  6. #6
    Fortis Fortuna Adiuvat Omega Man's Avatar
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    I'd also check battery connections.
    OM
    "You can do good or you can do well. Sooner or later they make you choose." MI5
    Mod Squad
    2009 F800GS 1994 TW200

  7. #7
    I appreciate all the great information everyone has contributed. A friend of mine discussed the problem with his mechanic who is a certified BMW tech and lead mechanic for a now defunct BMW dealer. Iím including his comments below. Given the symptoms, this seems about right, but Iíd be interested to hear any of your comments or thoughts.

    He says the problem is likely 100% electrical that given the circumstances it is most likely a poor connection or ground...that such a problem could be responsible for everything and cause such bizarre problems. The abs and Asc are related but have nothing to do with the engine issue.

    These bikes have the central chassis computer (ZFE) that control and coordinate all electrical functions of all components so an electron shortage(my terminology) could cause the multiple problems.

    He recommended that you check all wires and grounds....first the infamous battery terminals. He also recommends that you do have the fault codes checked at a BMW dealer . He said the dealer would have all up to date codes and software updates.

    That ZFE is programmed for that specific bike and only a dealer could work with it if necessary.

  8. #8
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    With all due respect to your certified mechanic, the ZFE has nothing to do with the ABS and ASC systems. The wheel speed sensors are wired directly to the ABS control unit, which is powered directly from the battery. Both front and rear wheel speed sensors are used by both the ABS and ASC, so I would check both of them.
    Karl
    2007 R1200ST

  9. #9
    Quote Originally Posted by kthutchinson View Post
    With all due respect to your certified mechanic, the ZFE has nothing to do with the ABS and ASC systems. The wheel speed sensors are wired directly to the ABS control unit, which is powered directly from the battery. Both front and rear wheel speed sensors are used by both the ABS and ASC, so I would check both of them.
    Thanks Karl...good to know. Iíll pass that along, and see what comes back. Iím hoping the BMW dealer here in Sarasota is open tomorrow, and I can get the fault codes read.

  10. #10
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    Quote Originally Posted by kthutchinson View Post
    With all due respect to your certified mechanic, the ZFE has nothing to do with the ABS and ASC systems. The wheel speed sensors are wired directly to the ABS control unit, which is powered directly from the battery. Both front and rear wheel speed sensors are used by both the ABS and ASC, so I would check both of them.
    Karl is right about checking the front sensor also. The ABS & ACS both look at speed differential of the wheels. If the front wheel is seen as low on speed the ASC will cut fuel and retard the spark thinking the bike is spinning the rear tire. I donít not think this would happen from a dead stop though. I think the ASC function is just a software program in the ZFE, donít think there is an separate module.
    Chuck Swenson
    MOA # 9162
    2010 R1200RT, 2003 F650cs (BMW #12 & 13)

  11. #11
    I went out and looked at the battery terminals, and at a glance, they appeared tight. Upon closer inspection, the negative terminal was a bit loose and required substantial tightening. Rode about 10 miles, and all worked well. Iíll let you all know what the fault codes tell after that gets done. Thanks again for all the excellent advice.

  12. #12
    We stopped by Haps BMW in Sarasota before our drive back to NE Florida to have the fault codes read. The bike had so many unrelated codes, that it almost had to be a ground problem. They cleared everything, and took it for a quick test ride. Everything went well, and no codes reappeared. We also had an uneventful 250 mile ride back to NE Florida. Iím going to conclude the problem must have been caused by the slightly loose negative battery terminal which I tightened back up.

    Thanks again for the offered advice.

    Happy New Year,

    Steve

  13. #13
    Fortis Fortuna Adiuvat Omega Man's Avatar
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    Quote Originally Posted by sailorscd View Post
    We stopped by Haps BMW in Sarasota before our drive back to NE Florida to have the fault codes read. The bike had so many unrelated codes, that it almost had to be a ground problem. They cleared everything, and took it for a quick test ride. Everything went well, and no codes reappeared. We also had an uneventful 250 mile ride back to NE Florida. Iím going to conclude the problem must have been caused by the slightly loose negative battery terminal which I tightened back up.

    Thanks again for the offered advice.

    Happy New Year,

    Steve
    Great! Always good to hear how things worked out.
    OM
    "You can do good or you can do well. Sooner or later they make you choose." MI5
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    2009 F800GS 1994 TW200

  14. #14
    Back in the saddle again mikegalbicka's Avatar
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    Got to love an easy and cheap fix. Good job.

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