I cant figure out the ABS - 2001 Honda ST1100

[jacob]

Hi there, I am very new to this website, and STs in general. I have done some research and figured out how to retrieve the codes on my 2001 Honda ST1100, and instead of getting one long flash and multiple short flashes, it just continues to give me long flashes. Once I exceed 6MPH the ABS light starts flashes like crazy. Any help is appreciated - Jacob

 

[jfheath]

Hi and welcome to the forum.

You will get a number of short flashes to indicate the fault code. It will store and display up to 2 fault codes - so you might get (For example) : F-L-A-S-H flash flash F-L-A-S-H flash flash flash. Repeated. To indicate fault codes 2 and 3.

If there are no faults, then I guess (but don't remember) that you just get the long flashes.

If it is in fault retrieval mode when you set off, the ABS light will continue to flash - which is actually a good way of testing that the sensor on each wheel is working, as it will do this in the garage when you spin each wheel independently.

Try clearing the fault codes. Then start again. Normally you enter fault daignosis mode by holding down the ABS switch when you turn on the ignition. If it goes into fault diagnosis mode by itself when you turn on the ignition, then suspect a fault in the ABS switch. It is a momentary contact switch, not an on/off switch. It is easy to remove and disconnect for testing.

 

[jacob]

Hi and welcome to the forum.

You will get a number of short flashes to indicate the fault code. It will store and display up to 2 fault codes - so you might get (For example) : F-L-A-S-H flash flash F-L-A-S-H flash flash flash. Repeated. To indicate fault codes 2 and 3.

If there are no faults, then I guess (but don't remember) that you just get the long flashes.

If it is in fault retrieval mode when you set off, the ABS light will continue to flash - which is actually a good way of testing that the sensor on each wheel is working, as it will do this in the garage when you spin each wheel independently.

Try clearing the fault codes. Then start again. Normally you enter fault daignosis mode by holding down the ABS switch when you turn on the ignition. If it goes into fault diagnosis mode by itself when you turn on the ignition, then suspect a fault in the ABS switch. It is a momentary contact switch, not an on/off switch. It is easy to remove and disconnect for testing.

I took the bike for a ride again today after clearing the non existent code, and I got 2 long flashes and 4 short flashes, does this mean Faulty rear modulator control motor system? or do the 2 long flashes change that?

 

[jfheath]

The long flashes are only there to separate the sequence of short flashes. The system will store Up to two fault codes. So it looks like yours is showing just one code. Fault code 4. Rear modulator contro motor.

But lets be sure about what is happening.

You cleared the fault codes and turned off the iginition.

What heppened to the ABS lights when you then turned on the ignition?
You went for a ride.
What happened to the ABS light after setting off?
When you came back, you turned off the ignition, and then entered fault code retrieval mode by turning on the ignition whilest holding down the ABS button.
It gave you a long flash, then another long flash followed by four short flashes, and then repeated the sequence.

Is that correct ?

My 2000 model wouldn't flash the fault codes unless fault retrieval mode was entered. If there was no fault to report, it didn't flash anything. Which is why I wondered if there was a fault in the Abs switch causing it to enter fault diagnosis mode when you were riding.

But rear control motor.

When you turn on the ignition, you should hear the motors whirring into life briefly. Put your hand on the rear ABS modular unit when you turn on the ignition. Can you feel it operating ?

If not then maybe it is a wiring / fusing / connector issue.

Check the level of your rear brake fluid. If you changed pads (for example) and pushed the fluid back into the rervoir, it could be overfull. This will prevent the modulator from turning, and will probably blow the fuse.
Check the fuse for the rear ABS.
Check the wiring and connectors for the modulator. It has 2 pairs of wires. One pair comes from the rear sensor. The other pair powers the motor. Don't be tempted to test that the motor works until you know Which lead is which and the sensor is diconnected.

When recovering faults, make sure you record the current faults with date and time, clear the fault codes and check that they are clear By recovering them again. That way you will know that any codes are new ones.

You do not need to go for a ride to check the modulator motor fault codes. Turning on the ignition should result in both of the modulators operating briefly. If they dont work, the fault code is recorded, so it will be stored straight away.

nb you will never get a sensor fault code if the ABS system doesn't arm itself when you set off. By that, I mean that the ABS light comes in, and after riding a short distance - a few tens of metres - the ABS light goes out.

To check that the sensors are at least producing some signals, put the bike on the centre stand, and clear the fault codes. Then enter fault code retrieval mode - nothing should be flashing. Spin the rear wheel as fast as you can. The ABS light should flash If the sensor is working. Then do the same for the front wheel - you will need help, or a mirror, or a video recorder to be able to observe this.

nb - this is all taken from my own observation with a UK 2000 ABS model. This was a long time ago, but I documented it at the time and subsequently posted it here on the forum. Your findings may differ slightly.

Article [11] - ST1100 - ABS Fault Finding | ST1100 Articles

Diagnosing a fault reported by the ECU on a Honda ST1100AY. ABSII ABS/CBS/TCS This information is taken from my own website - I wrote it up at the time - I am just revisiting it 13 years later. ABS The ABS is brilliant - it works. It gives a pulsing sensation through the brake levers -...

www.st-owners.com

 

[jacob]

The long flashes are only there to separate the sequence of short flashes. The system will store Up to two fault codes. So it looks like yours is showing just one code. Fault code 4. Rear modulator contro motor.

But lets be sure about what is happening.

You cleared the fault codes and turned off the iginition.

What heppened to the ABS lights when you then turned on the ignition?
You went for a ride.
What happened to the ABS light after setting off?
When you came back, you turned off the ignition, and then entered fault code retrieval mode by turning on the ignition whilest holding down the ABS button.
It gave you a long flash, then another long flash followed by four short flashes, and then repeated the sequence.

Is that correct ?

My 2000 model wouldn't flash the fault codes unless fault retrieval mode was entered. If there was no fault to report, it didn't flash anything. Which is why I wondered if there was a fault in the Abs switch causing it to enter fault diagnosis mode when you were riding.

But rear control motor.

When you turn on the ignition, you should hear the motors whirring into life briefly. Put your hand on the rear ABS modular unit when you turn on the ignition. Can you feel it operating ?

If not then maybe it is a wiring / fusing / connector issue.

Check the level of your rear brake fluid. If you changed pads (for example) and pushed the fluid back into the rervoir, it could be overfull. This will prevent the modulator from turning, and will probably blow the fuse.
Check the fuse for the rear ABS.
Check the wiring and connectors for the modulator. It has 2 pairs of wires. One pair comes from the rear sensor. The other pair powers the motor. Don't be tempted to test that the motor works until you know Which lead is which and the sensor is diconnected.

When recovering faults, make sure you record the current faults with date and time, clear the fault codes and check that they are clear By recovering them again. That way you will know that any codes are new ones.

You do not need to go for a ride to check the modulator motor fault codes. Turning on the ignition should result in both of the modulators operating briefly. If they dont work, the fault code is recorded, so it will be stored straight away.

nb you will never get a sensor fault code if the ABS system doesn't arm itself when you set off. By that, I mean that the ABS light comes in, and after riding a short distance - a few tens of metres - the ABS light goes out.

To check that the sensors are at least producing some signals, put the bike on the centre stand, and clear the fault codes. Then enter fault code retrieval mode - nothing should be flashing. Spin the rear wheel as fast as you can. The ABS light should flash If the sensor is working. Then do the same for the front wheel - you will need help, or a mirror, or a video recorder to be able to observe this.

nb - this is all taken from my own observation with a UK 2000 ABS model. This was a long time ago, but I documented it at the time and subsequently posted it here on the forum. Your findings may differ slightly.

Article [11] - ST1100 - ABS Fault Finding | ST1100 Articles

Diagnosing a fault reported by the ECU on a Honda ST1100AY. ABSII ABS/CBS/TCS This information is taken from my own website - I wrote it up at the time - I am just revisiting it 13 years later. ABS The ABS is brilliant - it works. It gives a pulsing sensation through the brake levers -...

www.st-owners.com

I believe that the ABS light was just steady on before I set off, The ABS light started flashing after I exceeded 6MPH.
I came back, entered fault retrieval mode, and it gave me a long flash, 4 short, one long and then repeated.

I was not able to feel anything happening in the ABS modulator.

The fuses for the ABS are fine and I will double-check the brake fluid.

 

[Ron]

How's your battery? The ABS system likes a fully charged and functioning battery.

 

[jacob]

How's your battery? The ABS system likes a fully charged and functioning battery.

I charged it fully just the other day.

 

[Uncle Phil]

As John noted, 4 flashes indicate 'Faulty rear modulator control motor system'.

 

[jfheath]

I was not able to feel anything happening in the ABS modulator.

It sounds like the ABS modulator motor or the wiring to it may be faulty. But check first - does the front modulator whirr when ignition is turned on ? It is under the fairing high up on the right hand side. I seem to remember it is almost impossible to get your hand on it with the fairing on.

If it does not, there may be an issue with whatever controls the modulators. However, the fault code is consistently showing the rear modulator as faulty, after the old faults have been cleared, so it does seem likely It is just the rear. But check the front anyway.

When my brake fluid was overfilled, the fuse blew as soon as I turned on the ignition. Bleeding some fluid out to get the reservoir level down, and replacing the fuse (again) solved that problem.

If you clear the fault codes, then turn on the ignition, and then check the fault codes again - does fault 4 pop up ? ie without having to ride the bike ?
If so, can you reproduce the similar error by disconnecting the front ABS modulator power supply (note that there are two connectors to the modulator - the power and the sensor - just disconnect the power. You would then get two error codes One for the front, one for the rear modulators.

If so, can you rig up a couple of wires with appropriate terminals to connect the wiring for the front to feed to the rear modulator to see if the fault remains with the rear, or whether the fault code is now to the disconnected front Modulator

Note that you must clear the faults from memory each time before doing a test.

You could then try the reverse and connect the front modulator to the connector for the rear.
This should help sort out whether the fault stays with the modulator, or stays with the wiring.

When doing stuff like this, I find that I need to write down what tests I do and what results I get each time Otherwise I lose track.

Maybe someone could advise on the dangers or safety of interchanging the wiring to the opposite modulator ? I seem to remember the manual suggesting this for the modulators themselves, but it has been a long time since I had my hands on an 1100.

 

[Smudgemo]

I just had something similar happen to me today. When I bought my bike in August, something was goofy with the lights, but I don't recall what was going on. They just started working normally the next time I rode it. Then yesterday, I was doing a couple of things and was curious if I could retrieve a fault code from August, so I tried but didn't get anything. Today I wanted to run a few errands and the ABS light was on until rolling, then steady flash. So I turn around to go home, grab the manual to figure out what's going on, and the fault code is just steady three second on, two second off flashes. I feel I'm a fairly sharp guy, but I really struggled to interpret this. Since it didn't seem like any sort of pattern, I focused on the matrix in 16-B-33 (I think that was the page) and gathered that I should check the connection for the ABS button.

Figured that was an easy as any place to start, so I pulled the sides, fake tank, left maintenance panel and pocket to get access. The connector was a little difficult to remove as it appears to have three barbs holding it, but in reality, the male connector on the switch side fits into an adapter which then plugs into the female connector in the harness. That male part has a single small barb in the middle that will allow the connector to be separated (assuming you have the same one as me, of course.)

Anyhow, I cleaned the old grease out with a tiny screwdriver and sprayed both parts with electronics contact cleaner. I gave the rubber donut gasket and the connectors some new silicon grease and put it back together, and the light started operating normally. Nothing wrong in 40 miles and two stops, so while it's hard to believe that was my issue, it sure seems to have been.

I made mention of the ride home when I bought it because that was the last time I recall playing with those buttons, and it seemed unlikely it just stopped working today for some other reason. Your first post sounds exactly like what I was seeing so I thought I'd mention it.

 

[jfheath]

Thanks @Smudgemo, that is a really useful bit of information, It might be worth Jacob going back to this. I did mention the possibility in my first reply:

If it is in fault retrieval mode when you set off, the ABS light will continue to flash..........

...... If it goes into fault diagnosis mode by itself when you turn on the ignition, then suspect a fault in the ABS switch.

I had assumed that this possibility had been explored, but reading through again, I am not certain that @jacob has investigated whether or not the switch is working.

@jacob - when you cleared the fault codes from memory, do you try to retrieve them again to make sure that the old fault codes have gone ? If they don't, the switch is faulty and your button pressing may be doing nothing. In which case, the fault code you are seeing is an old one.

This is important to know. If the electrical connection in the switch is permanently set to the same as when the button is pressed, then the bike will enter fault diagnosis mode when you turn on the ignition - just as if you had held the button down.

Maybe the ABS modulators do not whirr when the ABS switch is held down? I don't know, and cannot check, but it is a possibility. In which case, if you didn't actually check that the fault codes were cleared, you will be chasing the wrong problem.

Check the switch.

Let us know.

 

[jacob]

Hi there!

After going through the books process again I came down to the ABS rear modulator, when I put power to it it doesnt seem to crank over or do much. I'm not sure if that is because it's broken or if the modulator controller is broken thus making the motor wear out really fast.

I found someone selling parts for an 05 ST1300 and was wondering if the ABS parts are transferable between the 2.
Thanks,
Jacob.

 

[Upt' North]

Jacob,
I doubt that very much.
If you're thinking of replacing the modulator remember used ones are as old or older than yours. I would check locally for an ABS service centre, somewhere they can test and rebuild your unit or at least tell you if a rebuild is appropriate.
There are usually specialists in most areas, sometimes the more back street variety, that'll be cheaper probably.
If you are tempted by a used replacement then ebay UK usually has items for sale.
Good luck and the one below is in Vegas Baby.....
Upt'North.

 

[Upt' North]

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[jfheath]

There are two sets of wires plugged into the modulator. One pair for the sensor, one pair for the power. If you aren't hearing or feeling them cycle when ignition is turned on then check the power connection and the two abs fuses.

I seem to remember being horrified at the prospect of interchanging them to verify where the fault was. I had a Haynes manual at the time, I read it somewhere. Check the part numbers on fiches.

 

[jacob]

There are two sets of wires plugged into the modulator. One pair for the sensor, one pair for the power. If you aren't hearing or feeling them cycle when ignition is turned on then check the power connection and the two abs fuses.

I seem to remember being horrified at the prospect of interchanging them to verify where the fault was. I had a Haynes manual at the time, I read it somewhere. Check the part numbers on fiches.

I checked the ABS fuses and they were fine.
I tried putting power to the motor purely from the battery and it tries to crank for like half a second then stops. I assume it's supposed to turn for longer.

 

[jfheath]

I tried putting power to the motor purely from the battery and it tries to crank for like half a second then stops. I assume it's supposed to turn for longer.

I assume, but I don't know. It powers itself up in order to get the modulator to its correct point of its rotation before you set off. Whether this is determined by the ECU or whether it is a mechanical device that turns it off, I'm sorry, but I wouldn't know. I have never had need to do that to observe that behaviour. Does it rotate again, the next time you apply power ? Compare that behaviour with what happens at the other modulator.

I'm thinking of the sort of mechanism that used to be in windscreen wipers - you flick the sprung loaded stalk lever, to give it its initial power, and then remove it - but the motor doesn't turn off until the wipers are back to their start position. Its done with two switches in parallel. One on the stalk, and one on a part that is turning, operated by a cam. Goodness knows if that is the arrangement in the modulators. Its possible, but I suspect not - its a bit primitive when they have sensors and pulsars rings on other parts of the bike

Check the reservoir is not over full. It may stop the motor from turning