Persistant ABS problems

[mystic]

Spent ages trawling through the words of wisdom on this issue. Still uncertain as to what my next move should be!

2000 1150GS with ABS2 fitted.

Countless times I've reset the system (grounding from the diagnostic 'plug' ) ..... works fine ...... two ABS lights flashing together Start the engine .... no problem .... lights still flashing together. Move off and the ABS 'self test' begins, audible double 'clunk', and lights are now flashing alternately (suggesting the test has failed?)

Battery is 3+ years old and kept on an Optimate over the winter.
Have NEVER checked the ABS sensor gaps on either wheel

During my searches on the web, it was suggested that where the ABS 'self test' fails on riding away, it could be either a fault with the ABS modulator (sounds expensive!) or a wheel speed sensor.

Anyone experienced similar problems? Last thing I want to do is go trailing off to my BM dealer (unless there's no alternative!).

Done a search on adjusting the sensor gaps ...... just talks about using shims. What sort of shims?

Just need to know the order in which to eliminate things.

M.

 

[John Armstrong]

Does the ABS self test ok after riding it for a while then stop for a few seconds / minutes? If so change the battery, charge it up, then see if there's a problem

 

[(RIP) Bin Ridin]

Fit Odyssey batt.

 

[mystic]

Thanks John & BR. Before I splash out on a Hawker Odessey battery, is it possible the fault has something to do with the wheel speed sensors? What do you think?

M.

 

[DrFarkoff]

Thanks John & BR. Before I splash out on a Hawker Odessey battery, is it possible the fault has something to do with the wheel speed sensors? What do you think?

M.

Yes It must get a signal from both or it immediately goes into fault mode

If you have dual flashing lights after the engine is running it's feck all to do with the battery!

If they are alternate flashing once you press the starter it's a low voltage fault!

 

[BroX]

Have similar symptoms, and first checked the sensor gaps, which were ok. Since the clock in the HID frequently reset to 0:00h I thought it might be the battery. I bought the bike ('00 1150) 2nd hand so had no idea about its age. But even with the Odyssey fitted I kept the alternating lights after resets. Then the bike went for a service and they reported that it was probably 'something in the ABS unit'. Another thing to check for you (before you spend on a Odyssey) is the level of brake fluid in the ABS system under the tank (according to the BMW mechanic).

Good luck!

 

[ciderman gs]

have you checked the level in the battery if it is a wet cell mine on an optimate lost its water down to the lower level over the same sort of time. the shims that you have seen mentioned are to change the gap on the sensor and are between the sensor shoulder and the face of the rear drive and the front abs sensor bracket on the forks

 

[fatgser]

take it to a bmw dealer to get it diagnosed on the computer its cheap enough
you can always do the work your self

 

[DrFarkoff]

But even with the Odyssey fitted I kept the alternating lights after resets. Then the bike went for a service and they reported that it was probably 'something in the ABS unit'.

It's dead simple IF the lights alternate ONLY after you pres the starter button BUT before you move off it's the battery OR the starter drawing excessive current Any other time it's the ABS unit has a logged a fault

Re the Blue bit Do you still go there for service???

Another thing to check for you (before you spend on a Odyssey) is the level of brake fluid in the ABS system under the tank (according to the BMW mechanic).

What a load of Bollox this only applies to the bikes with Integral or Servo assisted ABS and it will flash the ABS lamp and go out Brakes will remain active so no worries there


A simpler thing is to do weekly or monthly checks on your bike Pads, tyres, lamps, horn, etc, ect, etc, If it don't work when you need it it's too late!

 

[mystic]

Thanks all for your imputs. Plenty to think about . Having read all of your responses, I'm inclined to take the bike down to my BM dealer and have a diagnostic computer test done to point me in the direction of the fault.

I'll let you know the outcome in due course.


M.

 

[BroX]

It's dead simple IF the lights alternate ONLY after you pres the starter button BUT before you move off it's the battery OR the starter drawing excessive current Any other time it's the ABS unit has a logged a fault

To clarify, after a reset the lights alternate AFTER moving off, NOT after pressing the starter button

Re the Blue bit Do you still go there for service???

Sounded a bit vague to me too.

What a load of Bollox this only applies to the bikes with Integral or Servo assisted ABS and it will flash the ABS lamp and go out Brakes will remain active so no worries there

The suggestion about the brake fluid level was given before he had even seen my bike, when I asked for possible causes.

Forgive me my ignorance, but why would this only apply to servo assisted ABS?

 

[DrFarkoff]

Forgive me my ignorance, but why would this only apply to servo assisted ABS?

Because they have seperate fluid reservoirs the handlebar and foot which ONLY feed to the servo ABS block i.e. the "Control circuit"
Then there is a seperate "wheel" circuit which is from the Servo ABS unit to the callipers

You can see the levels in the handlebar and footbrake reservoirs but you can't see under the tank! Hence the low fluid level warning

Easy test just look in at your pads if the pads are nearing the end of their life you are likely to be low on fluid

You should always change the fluid when you have fresh pads fitted not half worn ones! Because when you press the pistons back to fit new ones the brake fluid pisses out the overflow as the fluid level was suited to worn pads!