1150RT 2002 ABS failure

While riding the bike pressed the front brake hard'ish and the ABS warning light came on at 4Hz. Switched the ignition off and on, the self diagnosis passed, drove off the ABS light went out. Applied the rear brake hard no issue, applied the front brake and the ABS failure light came on (with the general light staying on), stopped applied the front and rear brake independently and the abs system sounded to be active. Switched off and on the ignition all appeared to be good until applied the front brake and again failure light came on.

Any guidance on what my next step's shop be?

thanks

While riding the bike pressed the front brake hard'ish and the ABS warning light came on at 4Hz. Switched the ignition off and on, the self diagnosis passed, drove off the ABS light went out. Applied the rear brake hard no issue, applied the front brake and the ABS failure light came on (with the general light staying on), stopped applied the front and rear brake independently and the abs system sounded to be active. Switched off and on the ignition all appeared to be good until applied the front brake and again failure light came on.

 

Any guidance on what my next step's shop be?

 

thanks

Morning Alba

We probably need a little more info before we help you much.

While riding the bike pressed the front brake hard'ish and the ABS warning light came on at 4Hz--Did you still have power assist when this happened?

Morning Alba

 

We probably need a little more info before we help you much.

 

While riding the bike pressed the front brake hard'ish and the ABS warning light came on at 4Hz--Did you still have power assist when this happened?

It felt like I had full power in the front however when applying the rear brake it felt under powered and not applying some front braking.

Morning Alba

 

We probably need a little more info before we help you much.

 

While riding the bike pressed the front brake hard'ish and the ABS warning light came on at 4Hz--Did you still have power assist when this happened?

 

It felt like I had full power in the front however when applying the rear brake it felt under powered and not applying some front braking.

Morning Alba

That sounds consistent with having rear servo assist with only residual on the front using the front lever.

Without knowing for sure if you had front front servo assist or not then we are kind of in the guessing game without the trapped brake failure codes.

It c-o-u-l-d be a failing front internal pressure sensor, or a sticking front brake lever switch, or ??????

If it fails again see if you have a functioning rear brake light using only the front lever.

Your symptoms sort of point to low fluid level in the under-fuel-tank ABS controller front reservoir but your dash warning lights don't exactly point to that.

If it fails again see if you have a functioning rear brake light using only the front lever.

Was easy and quick to create the fault as described. Start up the bike self diagnosis pass, pull away ABS light goes off, apply front brake hard'ish ABS fault light (flashing) and general light on.

Brake light comes on when applying front lever and brake light comes on when applying rear brake (levers tested separately).

Fluid level root cause?

If it fails again see if you have a functioning rear brake light using only the front lever.

 

Was easy and quick to create the fault as described. Start up the bike self diagnosis pass, pull away ABS light goes off, apply front brake hard'ish ABS fault light (flashing) and general light on.

 

Brake light comes on when applying front lever and brake light comes on when applying rear brake (levers tested separately).

 

Fluid level root cause?

Morning Alba

You can check the under-tank ABS controller fluid reservoirs but I would be surprised if that is the root issue (sure wouldn't hurt to check though)

The best "next step" would probably be to get a GS-911 or dealers computer on that bike to read the ABS failure codes (THAT should give a direction to look in)

Your brake light working properly pretty well verifies the external brake switches are working OK so that heavily points to the front internal (inside the ABS unit) pressure sensor but without an ABS failure code that is just a quick guess.

Not sure if this applies , but, had a similar issue with a friends 09rt. Loosened the front ABS sensor mount, reseated it and problem disappeared. He did have the front wheel removed previously so thought I'd start with making sure things installed properly. BTW his brakes did work while fault light was on.

So after waiting three weeks for BMW to run a diagnostic, the outcome is they will not rule out a pump failure but the fault is coming up as a rear pressure system failure. They did also say the break fluid looked past its best and with the break disc being at the bottom end of acceptable wear and with worn pads it could be this combination. But i did stamp on the rear break and no fault only when I pull the front so a little confused here.

I am in favour of replacing the break fluid and if there is still a fault then bypass the ABS.

I remember there was a couple who posted a detailed guide how to complete a fluid change on a ABS RT but I can't find it. If anyone could post the link I would be very grateful.

If anyone could post the link I would be very grateful.

Evo Brakes Part 1

EVO Brakes part 2

Excellent Cap, those were the ones I recall.