ABS Lights Flashing

Hello, my ABS light flashes alternately on 98 R1100GS. This has been typical until the first stop of the day and then it typically engages after the next start and the lights goes off. Now It never goes off on short trips and on my last good ride it finally engage about 100 miles later. I tried a reset and and then it flashes alternately immediately after I turn the key back on. I have the battery on a tender all the time and it seems to crank just fine. Should I pull the battery and have it load tested? It is about 2.5 years old. I just went to harbor freight to find an analog volt meter to pull codes but they are all digital. I use the same center pin used for the reset to pulll codes? I had the rear wheel off this weekend and checked the sensor clearance and it was .38 MM, so a little less than the .45MM min. But that would only trigger the alternating lights after rolling right? Thanks

I tried the 30 mph bump start and that didn't work. The voltage at standstill is 12.6 and drops to 9.6 on start-up. I'll try to gap the rear wheel sensor next.

I tried the 30 mph bump start and that didn't work. The voltage at standstill is 12.6 and drops to 9.6 on start-up. I'll try to gap the rear wheel sensor next.

Morning SmokinRZ

A little more info would help us help you identify the problem.

So, tell us EXACTLY when the lights originally start flashing, change flashing, or do something different? This can help us identify WHEN in the cycle that the problem appears.

The 9.6v on engine cranking can definitely trigger a low voltage fault.

At key-on, the two ABS lights should flash together and should continue to do so until the ABS self-test is complete (doesn't happen until you start to ride the bike away), at that time they should go out.

If the self-test fails, they will begin to flash alternately. The exact moment when they start to flash alternately is usually when the problem appears.

If, it happens before you start the engine then it is usually a system that is tested at first power-up.

If, it faults when you crank the engine then it is usually a low battery voltage problem.

If, it faults when you ride away then it could be the ABS controller, or possibly a wheel speed sensor.

SmokinRZ - your battery needs to be replaced. 12.6 is low for a resting battery, it should be around 12.8 v. And 9.6 at start-up is too low and triggering the ABS2 low voltage fault. Sounds like you were able to get it to reset after riding/recharging for a while, but now even that is getting tougher. If you have never pulled your starter motor, you might pull it off and clean up the shaft so it all moves freely, but really it sounds like your battery is done.

DR,

I can reset the ABS by grounding the center pin and holding the ABS reset button for 10 seconds and then the bottom light comes on.

I then turn off the key and switch it back on, and instantly I have alternating flashing lights. i do not even hit the starter and they go to flashing and this is while I have the battery hooked up to a battery tender. This was the part that had me thinking I have another issue besides voltage.

Michaelr,

This bike has always been finicky with the ABS low voltage. I bought the bike two and half years ago with a bad HES, so I only have experience with this battery from battery mart. It seems to crank just fine but I sure hope it is as simple as the battery. Like I mentioned, it finally engaged on the last ride a few weeks ago, but it took a couple of stops and a tank of fuel. I had it on the battery tender before I started off.

DR,

 

I can reset the ABS by grounding the center pin and holding the ABS reset button for 10 seconds and then the bottom light comes on.

 

I then turn off the key and switch it back on, and instantly I have alternating flashing lights. i do not even hit the starter and they go to flashing and this is while I have the battery hooked up to a battery tender. This was the part that had me thinking I have another issue besides voltage.

 

Michaelr,

 

This bike has always been finicky with the ABS low voltage. I bought the bike two and half years ago with a bad HES, so I only have experience with this battery from battery mart. It seems to crank just fine but I sure hope it is as simple as the battery. Like I mentioned, it finally engaged on the last ride a few weeks ago, but it took a couple of stops and a tank of fuel. I had it on the battery tender before I started off.

Morning SmokinRZ

IF, you did the reset correctly then you have other problems than a low voltage issue.

It sounds like you are getting the alternately flashing failure at initial key on (correct?)

If so & your battery voltage at key-on is over 12v then you more than likely have ABS controller issues (like a stuck piston, or electronics issues, or a shorted wheel sensor, or ??????

About all you can do at home is to verify that you don't have a shorted wheel sensor or high resistance connection issues into the ABS controller on the green 12v ign wire or on the large red 12v battery+ wire.

Sometimes resetting the ABS then pounding on the ABS unit with a rubber mallet while you key-on can get the unit working for a short time. IF (big if here) you can get the ABS working then quickly take the bike out on a dirt or gravel road & get the ABS to go into ABS mode for a long as possible to exercise the ABS internals.

Added: if you feel like a little work then find the green ign-on 12v wire going into the ABS connector then cut that wire at a place where you can access both ends of the cut.

Then add a length of wire to each cut end to extend the wire ends up to place where you can install a simple N/C push button switch.

This allows the green ign-on 12v wire to be switch controlled with a momentary push of the button.

By adding the switch you can simply push the button & release to re-initiate the ABS controller AFTER the engine has started & the charging system has raised the system voltage. You can also keep playing with (pushing) the button to try to get the ABS controller to re-initiate while riding.

Once (if) the ABS is booted, working, & the flashing lights go away then you then find a gravel road & exercise the ABS more often until it possibly works on every key-on ride away.

Yes, alternating flashing at initial key on.

I found a gravel parking lot a few weeks ago when it finally initialized and exercised both the front and rear several times. The system works great once initialized.

At this point I'm going to correct the air gap on the rear sensor and borrow a known good battery. Probably this weekend.

I will report back.

Thanks for the help.

That vintage RT prefers to have a battery in tip top shape to avoid a low volt error on start up. But it sounds maybe a little different

My '99 RT had a front wheel sensor go bad and had to be replaced. At first is was intermittent and replacing the battery seemed to cure it. Then, it acted up again and I checked the sensor gaps and set the rear from the maximum to the minimum specified gap and it seemed to cure it. But eventually the front sensor fully failed and finally the right diagnosis was made. As soon as I R&Red that sensor I never had that issue again. Man I hate intermittent electrical problems as they never seem to be acting up when you are doing diagnostics.

Afternoon SmokinRZ

Yes, alternating flashing at initial key on. That tells us that it isn't the normally found low battery voltage problem as that would cause it to delay fault until engine cranking.

I found a gravel parking lot a few weeks ago when it finally initialized and exercised both the front and rear several times. The system works great once initialized. --This is good news as it says the internal pistons are relatively free & the chain/shaft is capable of moving.

At this point I'm going to correct the air gap on the rear sensor and borrow a known good battery. --It really doesn't point to a wheel sensor excessive gap as a wheel sensor gap issue would cause the fault to show up at ride-off, not at key-on. It doesn't even point to an open wheel sensor circuit, as again, that would not fault until ride-off. It c-o-u-l-d be a shorted wheel sensor or shorted wheel sensor pig tail as (sometimes that can cause a fault at key-on)

I will report back.--Yes, please do that.

If you would like my 2 cents worth, My one year old battery (96 RT) would often give me the alternating flash, I thought i needed another battery *&^%$#. After testing it it seemed fine. Next I cleaned and cleaned each line connected to the battery terminals (scotch brite, 400 grit sandpaper etc) and the battery terminals themselves. Hooked it up and didn't have the alternating flash all season. Dave

I got some time this weekend to look at it again. I spent two hours cleaning all the front spokes and ABS trigger wheel as well as checking the air gap which was too big at .53 MM. The cleaning was just something on my list for cosmetic purpose. I tried one more time to reset the ABS holding down the button for almost a minute and this time it reset!

I hit the starter and it engaged within a few feet. I rode off to a nearby grassy lot and exercised the front back brakes multiple time. I then rode for a couple hours stopping for gas and food with no codes.

The only things I dd was check the air gap at the front wheel (a tight fit with several feeler gauges to check max clearance) and holding the button down a lot longer than the usual 8-10 seconds. I'm thinking that holding down the button longer is what did the trick. It had never been reset in the three years of my ownership. I also tried to pull the codes with a digital meter but couldn't make out the voltage fluctuations. I'm not sure if that had anything to do with correcting my problem. Now I keep it on a battery tender when not being ridden.

It looks like it might be fixed for now. Thanks to everyone that posted.

Glad you got it reset. Holding the reset for a minute doesn't hurt anything but isn't necessary as long as you are holding it down for 10 seconds. Failure to get a good ground to the middle pin on the port would also keep the reset from working. Did you actually adjust the sensor gap, or just check it? Once you successfully got the reset, the error codes in the ABS were erased, so there's nothing there to read.

I didn't have any shims so the sensors are out of spec both front and rear. The rear gap is too tight and the front gap too big. It is working great now so I'm reluctant to correct it. I tried to pull the codes prior to getting it to reset. I got fluctuations on the meter up to 12 volts. That was when I tried the rest one more time and had success.

Anton's ABS Faults article used to have a more detailed description of reading the faults. I don't know why or when it changed. The old article said that digital meters would not work reading the code because they reacted too slow. Either an analog meter, or just a 2ma LED would work.

Rear too tight - front too big - seems like an opportunity to move one of the shims from rear to front. There are usually several shims bunched together at each sensor.

I got some time this weekend to look at it again. I spent two hours cleaning all the front spokes and ABS trigger wheel as well as checking the air gap which was too big at .53 MM. The cleaning was just something on my list for cosmetic purpose. I tried one more time to reset the ABS holding down the button for almost a minute and this time it reset!

 

I hit the starter and it engaged within a few feet. I rode off to a nearby grassy lot and exercised the front back brakes multiple time. I then rode for a couple hours stopping for gas and food with no codes.

 

The only things I dd was check the air gap at the front wheel (a tight fit with several feeler gauges to check max clearance) and holding the button down a lot longer than the usual 8-10 seconds. I'm thinking that holding down the button longer is what did the trick. It had never been reset in the three years of my ownership. I also tried to pull the codes with a digital meter but couldn't make out the voltage fluctuations. I'm not sure if that had anything to do with correcting my problem. Now I keep it on a battery tender when not being ridden.

 

It looks like it might be fixed for now. Thanks to everyone that posted.

 

Morning SmokinRZ

You need to eventually set the wheel sensor gaps Too tight is not an issue UNLESS the sensor hits the tone ring & damages it.

But, keep in mind that wheel speed sensor gaps WILL NOT & CAN NOT case a fault UNTIL you ride off. So if are/were getting a failure at key-on or before ride-off then your problem isn't & wasn't speeds sensor gaps.

Latest update:

I have been keeping the bike on the battery tender at home and everything was going fine, no more flashing lights.

Then on the third morning of a New Mexico trip, I got the alternating flashing lights after start up on a chilly morning. After a few miles, I switched it off and restarted and it initialized once underway with no more issues for the rest of the day.

The fourth morning was even colder in the lower 50s and the alternating lights returned and never went off even after multiple fuel stops. Now I would like to pull the codes to confirm the low voltage condition.

I only have a digital meter. Can I just buy an LED test light or does it have to be built with a resistor and switch?

Would it be easier to just find an old analog meter? Thanks!

Latest update:

 

I have been keeping the bike on the battery tender at home and everything was going fine, no more flashing lights.

 

Then on the third morning of a New Mexico trip, I got the alternating flashing lights after start up on a chilly morning. After a few miles, I switched it off and restarted and it initialized once underway with no more issues for the rest of the day.

 

The fourth morning was even colder in the lower 50s and the alternating lights returned and never went off even after multiple fuel stops. Now I would like to pull the codes to confirm the low voltage condition.

 

I only have a digital meter. Can I just buy an LED test light or does it have to be built with a resistor and switch?

 

Would it be easier to just find an old analog meter? Thanks!

Evening SmokinRZ

I haven't ever tried a LED test light but I have my doubts.

You can use an LED but I have had mixed results using one & last time I tried I had to reverse the LED & go between 12v & the test terminal rather than to ground.

The old little (cheap) Radio Shack analog meters seem to work the best. Not the most accurate but they give nice needle deflections that are easy to distinguish.

That cold start then ABS acting up kind of points to a low system voltage (low battery) at start up --EXACTLY WHEN did the lights start flashing alternately? If right after cold engine cranking then suspect a low capacity battery issue. If it faulted at initial key-on, or faulted after ride-off then suspect something else

The lights started flashing immediately after start-up. I suspect the low voltage is the issue but I'm a little confused as to why they don't go off after the first fuel stop. They always went off before until just recently. Maybe the battery is just getting older.

The bike had been sitting for a few years when I got it and the negative battery cable connection was badly corroded. That is another area I need to revisit.

When I bought my digital meter 25 years ago I really thought I was adding some fancy equipment to my tool box, haha! Great tip on the analog meter, I will pick one up and report back. Thanks again DR for sharing your wealth of knowledge.

The lights started flashing immediately after start-up. I suspect the low voltage is the issue but I'm a little confused as to why they don't go off after the first fuel stop. They always went off before until just recently. Maybe the battery is just getting older.

 

The bike had been sitting for a few years when I got it and the negative battery cable connection was badly corroded. That is another area I need to revisit.

 

When I bought my digital meter 25 years ago I really thought I was adding some fancy equipment to my tool box, haha! Great tip on the analog meter, I will pick one up and report back. Thanks again DR for sharing your wealth of knowledge.

Morning SmokinRZ

If you suspect low system voltage (sounds like it might be) then you can locate the green 12v (12v @ ign-switch-on) wire going into the ABS controller (ABS module), then cut that green wire, then add wire extensions to both ends of that cut green wire, then run them out to place you can easily access.

Next simply install a N/C push button switch on the extended green wires. (ie switch Normally is Closed then goes open when you push the button).

This switch then allows the ABS system to re-boot & re-energies AFTER the engine is started or even at a stop light. Just push the button for a few seconds to break 12v power into the ABS controller then when switch is released the ABS re-initiates. The best part of this is it allows the ABS to initiate with the engine running so battery voltage it much higher due to running alternator output.

It's often the case that a battery monitor / 'intelligent' charger doesn't actually top up the battery to its full capacity, if you normally keep it permanently connected when out-of-season.

Before you lash out the loot for a new battery, because as DR expertly says above that the issue is no-doubt due to low-capacity, try giving yours a full charge for a day with a 4-Amp regular charger that really warms the battery through and makes its hair stand on end.

You might get a nice surprise next time you push the button on a cold-start.

Remember, that if you have to lift the battery off the bike to charge it thoroughly, always unhook the neg-pole first and wrap the cable briefly with Insulting Tape.

When re-installing, connect the Pos-pole first before bolting the neg-pole down to the battery terminal.

Then, turn on the key but don't start the motor. Wind the throttle slowly from closed to fully-open a couple of times to reset the ECU's Throttle Position Sensor.

Switch off, on again and hit the starter button.

Then smile.

Incidentally, on the subject of new battery purchase, I now swear by the lightweight small-sized Lithium-Ion-Iron-Potassium jobbies, known originally as Li-On batteries when they used to cost a fortune.

That Li-On really roars the bike into life on all occasions. Even on the coldest of mornings, warm its fur by an initial attempt at starting, to wake it up, then after a few seconds, hit the button again and hear that crank spin like gangbusters.

 

Remember, that if you have to lift the battery off the bike to charge it thoroughly, always unhook the neg-pole first and wrap the cable briefly with Insulting Tape.

When re-installing, connect the Pos-pole first before bolting the neg-pole down to the battery terminal.

 

Then, turn on the key but don't start the motor. Wind the throttle slowly from closed to fully-open a couple of times to reset the ECU's Throttle Position Sensor.

Switch off, on again and hit the starter button.

Then smile.

 

.

Morning ALan

That (TPS relearn) is not needed on the OP's BMW 1100 Ma 2.2 bike as the 1100 Ma 2.2 doesn't use a learnable ECU.

I got my analog meter and I get a consistent 7 needle drops which translates to faulty ABS module.

The reset takes more than 8 seconds which according to this Japan vendor http://bmwk10075abs1fix.web.fc2.com/index.html means I have a faulty ABS ECU which makes sense because the abs works great once initialized. I have "exercised" it many times trying to loosen it up and it works great if it initializes.

There are some other connections to clean at the module, so I need to get some Deoxit. Assuming I run out of self repair options, would I be able to change out the ABS ECU from a used unit?

I compared the cranking voltage to my other bike (99 1100GS) and they both dip slightly below 10 volts for a second before firing. Also, the bike (98 1100GS) with the faulty ABS puts out 13.5-13.6 volts at the battery while the good bike puts out 13.7-13.8 volts. They both have the same brand battery.

Morning SmokinRZ

I got my analog meter and I get a consistent 7 needle drops which translates to faulty ABS module. --Yes, unfortunately that doesn't tell us what is wrong with the module. But it is a good indication of function anyhow.

The reset takes more than 8 seconds which according to this Japan vendor http://bmwk10075abs1fix.web.fc2.com/index.html means I have a faulty ABS ECU which makes sense because the abs works great once initialized. I have "exercised" it many times trying to loosen it up and it works great if it initializes.--I'm not sure I would put much stock in this as I have seen some good ones that take a good solid 8 seconds + & sometimes up to 10 seconds to re-set. It's the fact that it NEEDS to be re-set that causes concern.

There are some other connections to clean at the module, so I need to get some Deoxit. --This sure wouldn't hurt but I have a feeling that it won't be the answer.

Assuming I run out of self repair options, would I be able to change out the ABS ECU from a used unit?--Yes, BUT!, finding a GOOD USED early GS unit will be difficult. Do you need ABS???? If not then removing your entire ABS system is also an option that permanently eliminates ABS problems. Not a big deal to remove on the ABS-2 systems.

I compared the cranking voltage to my other bike (99 1100GS) and they both dip slightly below 10 volts for a second before firing. Also, the bike (98 1100GS) with the faulty ABS puts out 13.5-13.6 volts at the battery while the good bike puts out 13.7-13.8 volts. They both have the same brand battery. --This could have some effect but according to one of your above posts it defaults at key-on (not engine cranking) so it is already in default BEFORE cranking even begins.