'96 R1100 RT - no ABS, no warning lights

[Trobinson]

I'm pretty sure my '96 R1100 RT has ABS brakes since it has the sensors front and rear and the Brembo calipers mentioned in the Clymer manual for ABS II. However, I have been able to lock up the rear brakes twice under hard braking. I have no warning lights and the brakes feel fine with lots of power available. Last night really made me want to check into this as the rear got a little sideways as traffic was stopping quickly and I was heading between cars to avoid a collision (partly my fault for being too close for which I've chastised myself plenty). I don't see anywhere that there is a fuse for an ABS pump and I haven't seen a distribution block either unless it's under the air box.

 

Tom

[roger 04 rt]

There isn't a fuse, it is hardwired to the battery and the key switch.

 

Here's its location.

 

[Twinsig]

Man! That's a nice battery!

[dirtrider]

Morning Tom

 

On the 1100 ABS-2 systems there is an ABS relay in the fuse box. That only controls the dash warning lights. There is also a main power relay (under the sliding cover on the side of the ABS controller) & that is for the piston movement power motor.

 

In most cases, if the main power relay fails the ABS warning lights will come on as the ABS unit can't do it's internal tests or ride off tests.

 

But, if the ABS relay in the fuse box fails or is removed the warning lights won't come on.

 

SO, with key on & engine not started does your dash ABS lights flash? If so then your relay is probably in place & working.

 

If you have ABS dash lights at key on & they go out by themselves (& remain off) then you probably have some ABS available.

 

Your older 1100 (ABS-2) is a slow responding system that can be a bit limited in response time. It also has the bad habit of releasing the front brake due to rear wheel lock up thinking the rear wheel is lifting off the road.

 

Also, things like sticking rear brake parts (like pistons & pins) can really hinder quick rear brake release so even if the ABS is functional the rear brake can be slow to release.

 

If your dash warning lights flash then go off & remain off while riding then you probably have ABS available.

 

To test for ABS operation-- find a dirt or gravel road then do some limited hard braking to see if the brakes actually do prevent wheel lock up. (try the rear alone first). Be sure to pull the clutch lever in first to prevent engine connection from effecting rear wheel release.

 

If the brakes lock up for any distance be sure to manually release the brakes quickly to prevent lack of bike stabilization. That also means your ABS system isn't working properly.

 

[Trobinson]

DR,

 

No ABS lights at all. I'll have to check the relay, but for now I have solid braking power. Is the ABS light on the switch to the left that says "ABS" on it? I don't see any lights on the dash panel with ABS on them.

[dirtrider]

Afternoon Tom

 

That light on the ABS switch is NOT the ABS failure light or lights.

 

You should have 2 lights on the dash itself (location & function should be shown in your riders manual).

 

At key-on, the two ABS lights should flash together, then both go out as you ride away.

 

If you don't have the flashing dash lights at key-on then look for the possibility of someone having removed the ABS relay in the fuse box.

 

Unlike the BMW 1150 I-ABS system-- on the 1100 ABS-2 system you will have fully functional brakes even if the ABS controller is not working as the braking goes through the ABS controller but is simply a pass through until the vehicle enters as ABS event.

 

[Edgar]

It is easy to remove the light bulbs from the warning lights on the dash to stoping the flashing on a misbehaving ABS unit. Check for missing light bulbs first then check the relay that's under the tank on the right side of the ABS, under the black panel.

 

The 2 ABS lights are stacked just to the right of the neutral light.

[dirtrider]

Afternoon Edgar

 

Even with the bulbs removed he should be able to hear the relay clicking with the key on (engine not started).

 

If the relay is clicking then possibly the bulbs removed, if no relay clicking then probably relay removed or failed.

 

[Edgar]

With the light bulbs removed you do not hear any clicking or flashing with the key on and engine not running. It is quiet after the engine is running too.

 

[dirtrider]

Afternoon Edgar

 

The bulbs have nothing to do with the relay operation so it (the relay) still clicks even with the bulbs removed.

 

[Edgar]

DR

I don't want to argue, but I have done this fix three times on three different R1100's with the same results. Remove the lights... stop noise and flashing lights. Don't know what to tell you but it quiets everything down.

[Trobinson]

I checked last night prior to going home and I can hear the relay in the relay box under the seat clicking. I recall hearing this before, but didn't know what it was for so I dismissed it since the bike performs fine. I'll have to dig into the ABS relay in the next few weekends to see what's going on there.

 

Regarding the lights they are obviously not working (either removed or burned out). This is just another item the PO did some sort of workaround on rather than fix the problem. Oh well. Regarding lights and relays (not wanting to argue) if the relay is energizing the lights through dry contacts then the relay will work regardless of whether the lights are there or not. If the voltage to energize the coil goes through the lights then removing them will kill the relay. This does not seem to be the case here.

[dirtrider]

Afternoon Tom

 

You could very well have burnt out bulbs or even removed bulbs IF the relay is clicking.

 

Your ABS should have 2 dash lights-- One light is powered through fuse #1 & the ABS controller provides the ground path to light that light.

 

The other dash light is powered from the ABS warning relay. That relay (pull-in-coil) is DIRECT powered from the ignition circuit (12v) & the ABS controller provides the ground path to pull the relay pull-in-coil.

 

That 2nd dash "light" is powered from that same ign circuit PRIOR to the going through the relay so when the ABS controller pulls the relay armature in the relay contacts simply hook that 12v power to the bulb (therefore the relay will work no matter (if) a bulb is in the socket or not).

 

If you hear the relay clicking that is the ABS controller pulsing (that ABS relay) trying to flash the dash light.

 

That probably also means the ABS controller still has it's main wire harness connected.

 

You can get you dash lights working if you want but my guess is that will just point to a failed ABS controller as neither dash light is needed for the ABS to actually function & after your rear wheel lock-up it is doubtful that your ABS is working.

 

Once you have some lights to look at you can T-R-Y an ABS reset but that seldom works for very long.

 

The usual cause of the 1100 ABS-2 failure is a wheel sensor issue (like air gap, or injured wire) or the ABS controller itself having a stuck piston, or a shaft motor relay issue, or some sort of power failure.

 

[Galactic Greyhound]

Hi Tom,

 

See if this helps - you have ABS2 (ABSII) fitted to your bike:

 

http://www.largiader.com/abs/absfault.html

[Trobinson]

I finally got to removing the instrument cluster to check the ABS bulbs and sure enough they were removed. got replacements at a local auto parts store. So now I can see both are flashing alternately. I tried a short ride around the parking lot here, but nothing changed. I expect I need to try resetting the system. I'm going to get the rear tire replaced Saturday so I think I'll see if the dealer will read the codes for free. For now I removed the relay so only the top bulb flashes (which I can deal with).

[Limecreek]

Tom - make sure your battery is completely charged. The slightest drop in voltage can create a fault with the ABS2 system during start-up - at least that has been my experience.

 

Assuming the battery is fairly new and the connections are good, I'd put it on a trickle charger and try again after it is completely charged.

[Trobinson]

LC,

 

I put a new battery in it recently. Haven't had a chance to get the codes (just found the connector this morning) but plan to in the next few days as I need to get a test light.