ABS Issue

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Joined
Apr 28, 2024
Messages
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Location
La Crosse, WI
I have a 2008 that’s new to me. The front tire was shot so I replaced it. I followed instructions for removing and replacing the front wheel and everything seemed as expected. When starting the engine, the ABS light comes on for a few seconds and then shuts off (normal). I did not test the ABS before removing the wheel (my bad).

I took the bike to a parking lot to practice quick stops. After stopping hard, the ABS light started flashing. Turn off the engine, start the engine, ABS light normal. Do another hard stop, ABS light starts flashing until another power cycle. During the hard stops, I didn’t feel any pulsing.

I’m assuming I have a problem but I thought it was odd that the system checks out ok at startup and the light never stays on solid. I tend to overthink things and before I dig in, I want to make sure I have a problem

I searched enough to check the simple things like the lever and brake pedal first. I don’t have the harness to check the fault codes but I think I can make one. I have the Haynes manual and the Yamaha on is on order.

Do I need to dig in or does the light normally flash after activating the ABS? I did my best to search but didn’t run across this situation.

Thanks in advance for any help

Scott
2008, lots of miles
La Crosse, WI
 
According to the service manual, if the ABS light flashes while riding, there is no problem with the function of the ABS. However, the ABS ECU input has unstable factors.

The only good news is that Yamaha claims that the brakes work normally when the AbS fails.
 
Thanks for the reply @Diablo1. I caught a look at a service manual last night and read the same thing so at least I know the brakes will still work but I really want the ABS functional - it was a non-negotiable for me when I was looking for a bike.

It's been a busy couple of days but when I get a chance at a few hours in the garage, I am going to inspect and clean the front and rear sensors and clean/lube the rear brake pedal, I think it's sticking. I took it to the store last night and did some hard stops with only the front brakes and the ABS light did not come on. My money is on the rear brake pedal but it won't hurt to clean and put a thin coating of grease on the sensors.

I appreciate your help
 
Yes, clean the sensors because the magnets pick up iron dust and that can interfere with the signals. Also check for any stored ABS error codes. Good luck.
 
... and clean/lube the rear brake pedal, I think it's sticking. ...

Sticking rear brake pedal is a very common cause of the ABS light showing. I thought from your first post you'd checked for that, or I would have suggested it earlier.
 
Sorry for the lack of clarity in my original post ... I hadn't touched it before I posted and I should have made that clear.

I finally had a chance to hang out in the garage and go through this. The rear brake pedal was badly in need of cleaning and grease. Before I worked on it, it barely went back up when working it with my hand. Now it's clean and works as expected.

I pulled the diagnostic codes and the only thing in there was a 30 which I cleared.

I pulled the front ABS sensor and it was clean. I sprayed it with ACF-50 for good measure.

I removed the screw on the rear sensor but could not get it to budge. Any best practices on getting it off without ruining anything? PB Blaster?

In the end, I took it back to the parking lot and could not get the ABS light to flash so the rear brake pedal was the likely culprit.

Thanks again

Scott
 
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When you rode the bike, were you able to activate the ABS and feel the pulsing in the brake lever and brake pedal? That’s the only way to know the ABS is working.
 
...
I removed the screw on the rear sensor but could not get it to budge. Any best practices on getting it off without ruining anything? PB Blaster?

In the end, I took it back to the parking lot and could not get the ABS light to flash so the rear brake pedal was the likely culprit.

Thanks again

Scott
Good that it was as simple as the sticking brake pedal, as i said, quite common.

As for taking off the rear sensor, my suggestion would be using penetrating oil all round the flat part, leave for a while (24 hours?), then use a piece of wood as a punch against the top edge of the flat above the screw hole, tap the wood with a hammer. Don't use a metal punch, and don't use heat, on your 2008 the sensor includes a magnet that could be damaged by shock or high temperatures, though it's unlikely you'd get it up to the sort of temperature that would damage it.

If the wooden punch and hammer moves it a bit, use it underneath so as to rock the sensor plate clockwise then counterclockwise. If this works it will free up and should eventually work its way out. Whatever you do, don't pull on its cable.

In the limit, there's no real need to remove it, it's perfectly possible to remove and replace the rear wheel with the sensor in situ, though there's a greater risk of damaging its cable.

I suppose, with the wheel off, you coiuld try drifting it out from the inside, though, again, use a piece of wood or plastic as a punch.
 
When you rode the bike, were you able to activate the ABS and feel the pulsing in the brake lever and brake pedal? That’s the only way to know the ABS is working.
Hmm, I’ll try it again to make certain it pulses. I’m stopping pretty well from about 35 mph but I may need to squeeze and press even harder to really test it. I should probably look at the fuses to make sure they are good as well.
 
Good that it was as simple as the sticking brake pedal, as i said, quite common.

As for taking off the rear sensor, my suggestion would be using penetrating oil all round the flat part, leave for a while (24 hours?), then use a piece of wood as a punch against the top edge of the flat above the screw hole, tap the wood with a hammer. Don't use a metal punch, and don't use heat, on your 2008 the sensor includes a magnet that could be damaged by shock or high temperatures, though it's unlikely you'd get it up to the sort of temperature that would damage it.

If the wooden punch and hammer moves it a bit, use it underneath so as to rock the sensor plate clockwise then counterclockwise. If this works it will free up and should eventually work its way out. Whatever you do, don't pull on its cable.

In the limit, there's no real need to remove it, it's perfectly possible to remove and replace the rear wheel with the sensor in situ, though there's a greater risk of damaging its cable.

I suppose, with the wheel off, you coiuld try drifting it out from the inside, though, again, use a piece of wood or plastic as a punch.
The wood is a good idea. Thanks. I wanted to make sure it moves up and down (twists).
 
As for taking off the rear sensor, my suggestion would be using penetrating oil all round the flat part, leave for a while (24 hours?), then use a piece of wood as a punch against the top edge of the flat above the screw hole, tap the wood with a hammer. Don't use a metal punch, and don't use heat, on your 2008 the sensor includes a magnet that could be damaged by shock or high temperatures, though it's unlikely you'd get it up to the sort of temperature that would damage it.


Take this advice from the ever-wise mcatrophy certainly. My '06 was corroded to the point that tapping was not completely effective. I had to grasp the tab with vice grips, twist several times back and forth, and then pull. Remove corrosion from the tab with carborundum paper. Don't get a file or steel wool anywhere near it. Coat the sensor cylinder walls (not the flat end of the cylinder) and the tab surface with anti-seize before reinstalling.
 
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Just another thought, when (if) you get it out, on replacing it, put a very thin smear of something like copper-impregnated grease (usually sold for brake applications) on it, and on the screw thread. Makes removal next time easy.
 
If you've got ACF-50 lying around squirt that on the sensor. It has penetrating/creeping properties that will actually get in there and dissolve some corrosion making it easier to remove. The stuff is the bomb. It's used in aircraft applications and really is fantastic.

If you don't like aerosol spray they also have a liquid version in a pump bottle.

https://www.amazon.com/ACF-50-Anti-...0&qid=1715860796&sprefix=acf-50,aps,92&sr=8-1
 
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