ABS is MIA

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RadioHowie

I Miss Beemerdons!
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Location
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Leaving the office yesterday, I'm at an intersection waiting for the green.

I'm in the far right lane of a six lane intersection (three per direction). The inside lane is left turn, the middle is straight only and the far right, outside lane where I'm sitting, is go straight or turn right.

I'm third in line waiting for the green. Two cages in front of me. To my left, in the middle lane, are two panel vans. E-150 Econonline work vans, if you know the type I' m talking about.

The left turn lane gets an early left arrow and the 5 or 6 cars waiting there go. The "go straight" lights turn green, the two cars ahead of me leave and I begin to accelerate to go through the intersection.

I didn't really pay any attention to the two vans to my left, other than they were beginning to move.

Just as I get to the crosswalk, a pedestrian steps out from in front of the first van right in my path!!!

This jackass (a woman by the way) had waited 'til the left turning vehicles had crossed crosswalk, THEN decided it was time to cross through a red light!

I didn't see her in the crosswalk as the two big-ass vans blocked her from my sight.

Fortunately, I didn't hit her, but my language probably took 10 years off her life.

Now that all the description if over, here's the problem...

When I slammed down HARD on both front and rear brakes...inches -- and I mean inches...away from this woman, my '04 ABS locked up both wheels and I did a Bo and Luke Duke sideways up to the crosswalk, almost hitting the woman with the broadside of my bike. She's a very lucky woman that 900 lbs of bike and biker didn't punt her into the middle of her next life.

After settling down, breathing hard, wiping the spittle out of my beard from the blue streak and working the pucker outta my ass, I took off for the remainder of my ride home.

About two, maybe three blocks later, it hit me...HARD!

I slid into the crosswalk.

The ABS didn't work! WTF?!?!

Later on the same ride home, with no traffic around, I attempted a couple of ABS encounters with my rear brake. No go -- bitch just locks up and slides like an oyster down your piehole. Tried again this morning going to the office, and again on the way home...samey-same...no ABS on the rear. I'm not sure if the front is affected...I'm not brave enough to grab THAT much front brake for no good reason.

No ABS light indicating a problem...just no ABS on the rear. You guys withOUT ABS know how easy it is to lock up that big rubber thingie out back. And I don't like it!

I'm hesitant to take my baby to the local dealer...they don't know an FJR from an RFK. Don't even carry crush washers for the oil drain bolt.

Anyone got an idea what can cause an ABS failure without a warning light indication? This situation just won't do. ABS has saved my bacon a couple of times, and I want it back.

 
Great riding. I've always wanted to do one of those sideways slide things, but envision the bike going into a roll, crushing me as it tumbled down the road.

Hmmm . . . . maybe you don't have the ABS model?

Seriously though - maybe a blown fuse? It might be an unplugged connector to the control module. It could be that simple.

Do you have Y.E.S.?

 
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Fuses and unplugged connectors should fault the system. Something is seriously wrong to not have ABS function and have no fault indications. Do you get any lights when your first turn the key? Probably best to let a dealer sort it - this would be one where Yamaha would probably cover any repairs out of warranty because of the safety implications.

There may be a low-speed threshold - most ABS systems have this. But it should be a fairly low threshold, perhaps 5 mph or so. (Sorry don't know the spec.) Any chance you weren't going fast enough?

I wouldn't worry about seeing if you can get the ABS to work on the front. Deserted road, flat, no debris, keep eyes up, and start seeing if you can get to lockup. With or without ABS, we all should be practicing getting the wheels to their lock threshold and it's not dangerous under controlled conditions.

- Mark

 
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Great riding. I've always wanted to do one of those sideways slide things, but envision the bike going into a roll, crushing me as it tumbled down the road.
Hmmm . . . . maybe you don't have the ABS model?
Must've been those few '04s that were mislabled?

Seriously though - maybe a blown fuse? It might be an unplugged connector to the control module. It could be that simple.
Haven't delved into the hardware yet. Was looking for responses to a basic "anyone had this happen to them?" type of issue.

Do you have Y.E.S.?
N.O. :(

 
Fuses and unplugged connectors should fault the system. Something is seriously wrong to not have ABS function and have no fault indications. Do you get any lights when your first turn the key? Probably best to let a dealer sort it - this would be one where Yamaha would probably cover any repairs out of warranty because of the safety implications.
ABS light comes on pre-crank, just like always...and then goes out.

There may be a low-speed threshold - most ABS systems have this. But it should be a fairly low threshold, perhaps 5 mph or so. (Sorry don't know the spec.) Any chance you weren't going fast enough?
I thought about the speed issue, but ABS ain't kickin' in at any speed on the rear. Used to be I could just give the brake pedal a good boot and have the ABS come clunking into play, to the point I could stop the bike safely at speed just using the rear...just press hard enough to engage the ABS, let it do its work, and slow down safely, skid free, at 100% effectiveness.

I wouldn't worry about seeing if you can get the ABS to work on the front. Deserted road, flat, no debris, keep eyes up, and start seeing if you can get to lockup. With or without ABS, we all should be practicing getting the wheels to their lock threshold and it's not dangerous under controlled conditions.
Ever done an unintended "stoppie"? I did one on my ZRX when an unattended cage left in neutral rolled down a driveway into my path. Scared the you-know-what out of me. Almost endo'd, but boy does THAT bike have great brakes. :)

 
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Welllll........if the light is illuminating, and going out, the ABS ECM is functioning and finding all is well. It doesn't light off the motor in it's self tests though, don't know if it even looks to see if it's there-just sensor and internal checks IFAIK. So check to see if you lost a relay or fuse for the motor. The other thought I had is that the sensors are not telling the ECM anything is happening when you lock the brakes, but common sense says the ECM would detect a sensor problem on it's start up self test, so I don't think the problem lies there. I would look for a motor problem right now were it mine, could be as simple as a bad/missing connection, corrosion, etc.

 
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On GenIIs you can activate both ABS pumps remotely with a switch dealers should have. If not, it's only a matter of shorting 2 wires on a harness in front of the bike, but I don't know which ones (do a search; it's here somewhere).

This test is even mentioned on the owner's manual for customers to feel how ABS works if desired, and definitely described in the service manual. Front and rear pumps activate alternately for one second each, until those 2 wires are not shorted anymore.

GenIs should have the same feature as the system is basically the same as GenIIs, with the exception of a 3rd input for the linked ABS feature.

Since disconnecting the O2 sensor doesn't trigger a CEL dash light, I doubt the ECU is that 'sensitive' on other systems as well. Want more proof? BMWs don't extinguish the ABS light until you move the bike forward some, in order to test the speed sensors. The FJR doesn't do that, so it's obviously not checking that correctly (can't test the system witout moving the bike). It also doesn't test the motors (can't hear them, like on BMWs).

So, I'd start with the fuses and checking all connections. Then the ABS test I mentioned above. And if still not working, go thru the diagnostics described in the service manual. Dealer would probably charge you an arm and a leg, so I'd definitely tackle the job myself. The good news is the problem is not going to get any worse by trying. And I'd definitely do that asap for obvious reasons. Good luck man.

JC

 
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Any update, Howie? (was linked here by you from the other guys ABS problem thread)

Have you done any troubleshooting on the problem since the initial post?

This sounds quite similar to the problem recently reported caused by the wheels being wrong year, sending no speed signals to the ABS ECU. Except being a 2nd gen there was also the no speedometer, no odometer symptom. Being yours is a 1st gen we have a separate speed sensor.

I'd say that your problem is either no signals from both of the wheel sensors for some reason, or else the ABS ECU is telling the hydraulic unit to pulse, but it isn't complying somehow.

If you run it on the center stand in gear, does the ABS light flash? That would confirm it can see the rear wheel sensor OK.

 
Any update, Howie? (was linked here by you from the other guys ABS problem thread)Have you done any troubleshooting on the problem since the initial post?

This sounds quite similar to the problem recently reported caused by the wheels being wrong year, sending no speed signals to the ABS ECU. Except being a 2nd gen there was also the no speedometer, no odometer symptom. Being yours is a 1st gen we have a separate speed sensor.

I'd say that your problem is either no signals from both of the wheel sensors for some reason, or else the ABS ECU is telling the hydraulic unit to pulse, but it isn't complying somehow.

If you run it on the center stand in gear, does the ABS light flash? That would confirm it can see the rear wheel sensor OK.
Well, earlier in the thread containing that link he mentions the lack of function . . . I'd say that was an update.

Although the centerstand rolling test hasn't been mentioned before.

 
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Some preliminaries:

I have designed these sorts of control systems in the past (aircraft ABS systems for fighters, etc.) and am quite familiar with their problems and solutions. DISCLAIMER: I have not looked at a functional block diagram for the FJR's ABS so I do not know the details of how this has been implemented on Gen 1 or Gen 2. ANOTHER DISCLAIMER: I am not a big fan of ABS for doing precision work. But it is OK for everyday "keep your ass out of the ditch" things like RH indicated in his OP...times when your attention is not 110% on your line and energy management. I wish my FJR had a switch to turn it on/off like the one in my Evo.

All that said, some thoughts: on startup, the initial built in test (IBIT) should go look at all the sensors and actuators in the ABS to determine if the capability exists to go into antilock under the right conditions...the lawyers would insist. If IBIT detects ANY fault, the ABS fault indicator should be lit & the system latched into fault mode. ABS would be unavailable and you would default to a straight mechanical system like RH has experienced above.

In the aircraft (A/C) world, we actually actuate all the functions in a "flight critical" system like ABS during IBIT. This is expensive because I must now build transducers into or alongside actuators so I can see them move when commanded then write the SW to tie it all together (this are where the real $ are BTW). Yamaha probably didn't spend that kind of $ designing/building this system. So this IBIT probably just looks at things like electrical continuity through sensors and actuators to make sure they are there, and operating within electrically acceptable limits. This is a SW task that should reside within the ECU. The fact that you are not seeing a latched fail condition on startup indicates to me that the IBIT is satisfied that all the sensors and actuators are in place and within tolerance.

While operating, a continuous BIT (CBIT) will run periodically in SW to make sure that the stuff is still out there and working OK as long as power is applied to the ECU. Any failure detected during CBIT should again light the indicator and latch out ABS operation. CBIT & IBIT functions will be very nearly the same coverage. One exception would be the stop-to-stop actuation typically done in an IBIT to get full coverage...this would not be done during CBIT for obvious reasons. The fact that you are not seeing a latched fail condition while driving indicates to me that the CBIT is satisfied that all the sensors and actuators are in place and within tolerance

Now to the operation...to work effectively, an ABS system need a clean (accurate and low noise) wheel speed indication (WSI) and a real speed reference to determine when/if WSI requires ABS. The requirement for a clean WSI dictates that there be a low speed threshold below which no ABS will be allowed. The problem here is digital aliasing. Below a certain speed, the digital control system in the ECU (I'm assuming it's a digital and not an analog system...) will not be able to reliably determine what the speed of the wheel is. So below this threshold it should not try to invoke the ABS. It will instead default to the mechanical. Someone above referred to 5 mph. This sounds about right if the ECU is operating at somewhere between 50 and 100 hz. Anyone know what the frame rate of the ECU is?

Low noise here usually means you digitally filter the sensor input BEFORE you use it to decide (logic functions) then manage with ABS (control functions). Digital filtering of ABS sensor inputs can be tough to do well for many reasons I won't go into here. And I know FOR A FACT that GM (Delco) does not do this well. A story for some other post.

Above this speed floor threshold, the system will try to activate the ABS schema whenever the WSI exceeds a threshold BELOW the speed reference. Note here that you can't use the same sensor signal for both. There needs to be 2 separate speed indications...the two different wheel speed would work OK in "most" instances. Once this threshold is tripped, the ABS actuators are powered and begin their dance (if they are functional) and the system does dynamically whatever it is designed to do. A note here: common ABS systems will NEVER give you 100% of what the system is physically capable of for a number of reasons. They will get you close but a very good rider who is "one with the machine" can eventually outperform an ABS in any situation. This is one of the biggest reasons why you typically do not see ABS at the highest levels of motor-sport.

RH's symptoms tell me the ECU believes the sensors and actuators are all there and within electrical spec. I believe the ECU is OK (SW functions) as well because of protections designers put into the SW to count SW fingers and toes during its own IBIT. It LOOKS to me like there could be a problem with one of the two speed reference signals OR the ABS HW isn't working...more on that in a bit. If either of the speed sensors is continuously indicating 0, the system may not engage. This is certainly true for the reference signal (what the control system considers to be "truth"). It CAN happen if the WSI never comes off 0 even if the reference does. This would be an example of a "latent" failure in the system, one that exists but can't be found during the BITs. If WSI never comes off 0, you would not automatically want to trigger ABS. It is likely a better design to wait for both speed signals to reach measurability (both above 5 mph say) and be in close agreement for a short period of time (1/2 sec?) before you "arm" the ABS. It is entirely possible to satisfy IBIT and CBIT checks and not deliver up a good speed signal. WSI sensors are usually optical or induction type systems where a magnet passes by a wire coil and induces a current flow. The sensor electronics (usually in the sensor body for A/C systems, but not always) look for the rising edge then indicate a digital "1" to the control system saying the mark just passed by. These marks are buffered in a counting register in the ECU. The count of these indications per unit time is an indication of the speed (requires a digital differentiation in SW: counts/unit time or count per frame...an inherently noisy operation). I SUSPECT the FJR sensor's output is wired directly to the ECU and the ECU is doing the heavy lifting of counting, differentiating and deciding simply because there is no digital bus on this bike. That means the 0 speed problem, if that's the issue, probably resides somewhere with the sensors.

Faced with this problem I would investigate the sensors first: put a multimeter across each sensor at the sensor and spin the wheels slowly so you can see the signal. If that doesn't indicate a problem, move to the ECU and do the same test. Do this for each of your speed sensors if you can. The two wheel sensors ought to be easy. If the sensors all come back OK then I would next check the actuation system (pumps, plumbing, etc.) to see if it is working. Find a way to activate the pump externally and make sure it is delivering pressure to the brakes. Don't know if this would be hard to do or not on the FJR. Maybe just do a good servicing and see if the ABS comes back?

If that system seems to be working, I would next suspect the ECU SW or input/output functions (HW & SW) on the control system side. These "functions" are actually hardwired analog filters that digital controllers use to interface with an analog world. They perform anti aliasing and surge protection types of activity, among others. If the sensors appear to be delivering good signals at the interface with the ECU and the pump is up, then the problem is likely in the ECU HW/SW and Yamaha probably needs to get involved.

Sorry this is so long. I'll keep monitoring to learn and chime in when I see an opening.

Cheers,

W2

 
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Post #9 indicates that there are two seperate pumps- where is the one for the front located? After doing extensive fumbling around on my Silverado abs system, I know that the usual abs system uses only one pump and a system of solenoid controlled valves to modulate different wheel's speed..

 
Any update, Howie? (was linked here by you from the other guys ABS problem thread)Have you done any troubleshooting on the problem since the initial post?
Not really.....it's not that I'm happy NOT having ABS, it's just that since it doesn't stop normal riding, I just haven't delved in to it. After all my OTHER problems, it got back-burner-ed.

This sounds quite similar to the problem recently reported caused by the wheels being wrong year, sending no speed signals to the ABS ECU. Except being a 2nd gen there was also the no speedometer, no odometer symptom. Being yours is a 1st gen we have a separate speed sensor.
Does "sound" like it, but no change in hardware of any kind. It was a "one day works -- next day doesn't" situation, but it wasn't exactly a one day from work-to-not-work scenario. I really don't remember when I last noticed it working, but I SURE did notice the first time it didn't! :ph34r:

I'd say that your problem is either no signals from both of the wheel sensors for some reason, or else the ABS ECU is telling the hydraulic unit to pulse, but it isn't complying somehow.
I'm guessing it's the second situation you describe, because

If you run it on the center stand in gear, does the ABS light flash? That would confirm it can see the rear wheel sensor OK.
Yes, the old "bike up on c-stand triggers the ABS light" test DOES work, so the rear wheel sensor is okay, the ECU notes the error. I'm thinking it's the ABS pump...either inoperative, or clogged/rusted, as described in the other ABS thread.

I need to hotwire the ABS coupler up by the battery and run the ABS function test ELP JC mentions in Post #9.

If a complete flush-and-wipe of DOT4 doesn't correct the problem, I'll dig deeper.

Is there any sort of "flush" liquid that could/should be used to help clean the system? Or just waste some new DOT4 Syn for flushing?

Gotta get me a MityVac soon!

 
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Post #9 indicates that there are two seperate pumps- where is the one for the front located? After doing extensive fumbling around on my Silverado abs system, I know that the usual abs system uses only one pump and a system of solenoid controlled valves to modulate different wheel's speed..
From what I gleaned studying my ABS Supplement Manual, there is only one pump, at least on the Gen I, and as you describe, solenoids control which end of the bike benefits from the ABS action. The fluid orifi (orifices?) controlled by the solenoids are fairly small, so crapola in the system could conceivably plug one or both, rendering the system useless.

However, delayed/neglected fluid maintenance could also cause corrosion in the solenoid valves, also ruining your day and your budget.

 
I read your post yesterday on the money saved on a 7 minute brake pad replacement. I don't suppose there is any chance that something got bumped or otherwise messed up at that time? Not saying that it would be likely for someone who does any amount of routine mechanical work but...

Good luck on finding a fix.

Ross

 
I believe there are two pumps and they're both powered by the same motor.
You are 100% correct on both accounts....two pumps....powered by one motor. I was thinking "1 motor = 1 pump". That's what I get for skimming the material. :)

abs-3.jpg


Damn, CM....are you EVER wrong? :D

 
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I read your post yesterday on the money saved on a 7 minute brake pad replacement. I don't suppose there is any chance that something got bumped or otherwise messed up at that time?
Nope...ABS failure pre-dates brake pad service by 18 months. :(

 
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