St1100 ABS Fault...many threads on subject.

[Grell72]

Morning All.
ABS problems...I have read many threads on the st1100 subject and has lead me to posting this.

My story...
Purchased a st as getting old and my bent over the tank days are number’d.
Looking over the bike to give it a once over for service etc and found the alternator as read on many posts has a habit of case fracture..
And mine was no exception.
So took it upon myself to strip the back end down to get to the well fitted item in question then got a local welding specialist to do some magic as they are expensive to buy but to see if it could be salvaged.
Job done and spin freely after heat had been applied through welding process..
Re assembled as required bit by bit and greased up and swing arm check for corrosion. Alternator wires re fitters one cable and only one wire with a plastic connector on it..
I never removed the rear ABS sensor as it seemed corroded in and did not want to do any damage so as the drive hub was taken off as a whole unit and laid on carpet floor...the rest was not to bad.
Re fitted hub unit and so forth...
Re fitted rear wheel and this is where I went wrong...the ABS ring was scraping the rear sensor as I aligned the wheel up wrong so scraped the sensor and thus thought that’s done it and carried on assembly..in the end I drilled out the sensor and replaced with a second hand one thinking this was the problem...it wasn’t.

Now for the question..
Prior to the strip down all was fine....All I get now is on the dash was a Christmas tree light illuminated..
1. The yellow TCS left hand lamp is on.
2. The red TCS light flashes continuously.
3. ABS light flashes continuously one of two lights ABS1 ABS 2. ABS 1 is not flashing. ABS 2 is.
4. Press the TCS Button on the left hand panel and the flashing TCS light goes out..
I have followed the usual fault code process but this makes no changes all lights just flash..
I have checked fuse and even removed the fuse to see if abs shuts down, no change plus the 30 amp fuse on both ABS modules front and rear taken out and cleaned.

I have bled the brakes as some blogs mention excessive fluid pressure...for modulators.
And some say ABS ECU module failure fitted on the left hand side upper fairing...
After checking all this they are still flashing..all wires are connected. I got to the point of removing both ABS ECU block connectors on the unit and switching ignition on and all lights still flash...
Before is ride it off a cliff and me obviously no on it any ideas as this is just beyond normal...

Any help is greatly appreciated...

 

[Grell72]

Forgot to mention battery is showing 12.5 volts and when started jumps to 14.4,5,6 volts and when loading the system as lights switched on it jumps to 13.7,8,9 volts variable at about 4000 rpm.

 

[Upt' North]

Firstly you're not old. Not on this forum anyway.
Secondly most faults that show up after work are as a direct result of what you've done.
So it's probably the rear sensor or bleeding procedure. I too have read that overfilling can cause the ABS idiot lights to flash.
Check the work on the rear sensor again. Connections, gap etc, is it interchangeable with the front sensor to check if the fault goes from rear to front, what is the fault code telling you, I'm not sure you've told us.
Is the new sensor OK?
Upt'North.

 

[jfheath]

Sorry you are having issues with this.

You did right not to try and get the sensor out- the bracket holding it is extremely fragile.
The air gap between the sensor and the pulsar ring is critical.
Make sure you have no fragments of metal on the face of the sensor. Eg strands from a wire brush. The face is magnetic, so attract such things easily.

I don't know the cause, but if you read through this report that I wrote many years back, I had a similar issue. Blackpool illuminations after messing around with the ABS bits and pieces.

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

There is a check that I discovered in that above link to test whether or not the sensor is generating signals.

At some point I decided to try the Windows trick of shutting everything down and starting it up again. I took it one step further and disconnect both computer modules from their connectors (having disconnected the battery). Left them a while and reconnected.

In my case, this worked. I might have accidentally done something else in the process, but if so, I couldn't tell you what it was. My suspicion is that there was a faulty connection somewhere, and unplugging the connectors cleaned up the pins. But I'm guessing.

There was also an issue with blown fuses - due to an overfull rear reservoir, but I think you have spotted that post.

----------------

PS - just spotted Ray's post, which he posted a nanosecond before mine. If you retrieve the fault codes, write down what both of them are. And do that BEFORE doing any of the stuff in my link above. Once you have cleared the fault codes, you will NEVER get another fault code indicating that the ABS sensor is faulty, until the problem is fixed. It can only throw a code if the ABS system is armed and working, and if the ABS sensor is faulty, it cannot arm itself. Catch 22. Are you old enough to remember Catch 22 ?

PPS - My experience is with the ABS2 version - a 2000 model with ABS TCS and CBS. I guess yours is similar as you mentions TCS.
(for anyone looking in who is allergic to acronyms - Antilock Braking System, Traction Control System, Combined Braking System).

 

[Grell72]

Firstly you're not old. Not on this forum anyway.
Secondly most faults that show up after work are as a direct result of what you've done.
So it's probably the rear sensor or bleeding procedure. I too have read that overfilling can cause the ABS idiot lights to flash.
Check the work on the rear sensor again. Connections, gap etc, is it interchangeable with the front sensor to check if the fault goes from rear to front, what is the fault code telling you, I'm not sure you've told us.
Is the new sensor OK?
Upt'North.

Thanks for the info..I’ll re bleed the brakes again and see...The rear ABS sensor is fitted with a shim and between the sensor plate and mounting bracket..I thought that the shim would give the correct air gap as cannot adjust to support the 2mm air gap....
I cannot get any codes as following the code retrieval sequence that is the usual way does not work all lights just flash...
Ignition on and pro TCS button etc then off..not a code flash in sight...
I will check the sensor again...

 

[Grell72]

Sorry you are having issues with this.

You did right not to try and get the sensor out- the bracket holding it is extremely fragile.
The air gap between the sensor and the pulsar ring is critical.
Make sure you have no fragments of metal on the face of the sensor. Eg strands from a wire brush. The face is magnetic, so attract such things easily.

I don't know the cause, but if you read through this report that I wrote many years back, I had a similar issue. Blackpool illuminations after messing around with the ABS bits and pieces.

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

There is a check that I discovered in that above link to test whether or not the sensor is generating signals.

At some point I decided to try the Windows trick of shutting everything down and starting it up again. I took it one step further and disconnect both computer modules from their connectors (having disconnected the battery). Left them a while and reconnected.

In my case, this worked. I might have accidentally done something else in the process, but if so, I couldn't tell you what it was. My suspicion is that there was a faulty connection somewhere, and unplugging the connectors cleaned up the pins. But I'm guessing.

There was also an issue with blown fuses - due to an overfull rear reservoir, but I think you have spotted that post.

----------------

PS - just spotted Ray's post, which he posted a nanosecond before mine. If you retrieve the fault codes, write down what both of them are. And do that BEFORE doing any of the stuff in my link above. Once you have cleared the fault codes, you will NEVER get another fault code indicating that the ABS sensor is faulty, until the problem is fixed. It can only throw a code if the ABS system is armed and working, and if the ABS sensor is faulty, it cannot arm itself. Catch 22. Are you old enough to remember Catch 22 ?

PPS - My experience is with the ABS2 version - a 2000 model with ABS TCS and CBS. I guess yours is similar as you mentions TCS.
(for anyone looking in who is allergic to acronyms - Antilock Braking System, Traction Control System, Combined Braking System).

 

[Grell72]

Thanks for the responses.
I have no code sequence as the lights just flash...even after following the code retrieval sequence.
Having fitted a Second hand ABS sensor as I thought that I had damaged the original one on initial rear wheel fitting and the ABS hub ring was scraping the ABS sensor and when checking the three wires were green as corroded when lifting the rubber cover and .thus drilled out the old and fitted second hand new...

I had,as said,disconnected both ABS ECU front connector blocks to ABS ECU unit..and switched on ignition and all lights still flash..I note that ABS won’t self check until reaching 5/6 mph to reset but When I did go out to check it stayed the same..
I have checked the rear brake modulator motor some say it should spin but mine just clicks and why should it spin when stationary...
I can assume it will be human error or something as I was the last to fiddle with it as they say if it ain’t broke don’t fix it...haha..
If a fault code could be found then I would have some Idea...I note your Microsoft reset process and should of done this to see if it does reset..I’ll try that one...
Just to say much appreciated for the advice...

 

[jfheath]

The lights flashing indicate something is wrong. Not a recognised fault, but it shouldn't do that.
The 1100 goes through a number of checks when you turn on the ignition. The first is to turn the front and rear modulators. This is for 2 reasons :
1) to make sure that they are working
2) to make sure the modulators are in the correct position. They do this by reading the position from the sensor as the modulator cycles. This is important because they must be able to pulse the brake line and it must start off by releasing pressure - not increasing it.
The first thing you hear when the ignition is turned on is the front and rear modulators whirring into life briefly. You can put your hand on them to feel them working (or not).
So each modulator has 4 wires going to it. 2 for the motor (1 connector), 2 for the sensor ( another connector). Blown fuses, damaged wire, unplugged connectors, overfull reservoir can all interfere with this process.

If the cycling of the modulators is successful, it then waits for the bike to start moving forward. When it does, it checks that the signals from both wheels are consistent. Its easy to imagine that it is checking that the wheels are going the same speed, but they are different diameters, so it has to compensate for that.
Doing a wheelie, dropping a wheel off a kerb or riding a bumpy road surface may interfere with this. If it passes this test the ABS and TCS systems are activated ready to spring into life if a wheel locks or if the rear wheel starts going faster compared to the front.

Get rid of the newcomer to the system. Unplug the new sensor at the conector and see what happens. Maybe that has a fault.

 

[happybikes]

The lights flashing indicate something is wrong. Not a recognised fault, but it shouldn't do that.
The 1100 goes through a number of checks when you turn on the ignition. The first is to turn the front and rear modulators. This is for 2 reasons :
1) to make sure that they are working
2) to make sure the modulators are in the correct position. They do this by reading the position from the sensor as the modulator cycles. This is important because they must be able to pulse the brake line and it must start off by releasing pressure - not increasing it.
The first thing you hear when the ignition is turned on is the front and rear modulators whirring into life briefly. You can put your hand on them to feel them working (or not).
So each modulator has 4 wires going to it. 2 for the motor (1 connector), 2 for the sensor ( another connector). Blown fuses, damaged wire, unplugged connectors, overfull reservoir can all interfere with this process.

If the cycling of the modulators is successful, it then waits for the bike to start moving forward. When it does, it checks that the signals from both wheels are consistent. Its easy to imagine that it is checking that the wheels are going the same speed, but they are different diameters, so it has to compensate for that.
Doing a wheelie, dropping a wheel off a kerb or riding a bumpy road surface may interfere with this. If it passes this test the ABS and TCS systems are activated ready to spring into life if a wheel locks or if the rear wheel starts going faster compared to the front.

Get rid of the newcomer to the system. Unplug the new sensor at the conector and see what happens. Maybe that has a fault.

Hi, I make and sell abs sensors for the st1100, www.happybikes.co.uk I can provide help on fault finding.
To check the sensor operation use a digital multimeter to measure the signal between the green and blue wires at the sensor connector.
The connector has to be plugged in so you may have to nick the insulation to get your probe on. turn the ignition on and rotate the wheel by hand, the voltage should jump between about 0.5v and 4v DC. The acual voltage isnt too critical but it has to be a clean jump. At least this will tell you if the sensors are faulty. your sensor probebly has a broken wire as it enters the sensor head. this cant be fixed as it usually breaks flush with the epoxy filler in the head.

 

[kiltman]

Hi, I make and sell abs sensors for the st1100, w

A few years ago I was in need for a new sensor for my 97 ABS, Your product was a good alternative to the OEM, and of course at a better price. The replacement was easy to install, the bonus was that the gap needed wasn’t as critical as the OEM sensor required to function properly. Thanks for that. I sold that bike last year and now have a newer model and in the event that I have to replace a sensor in the future I will select your product again. Welcome to the forum

 

[Uncle Phil]

Just went through an ABSII problem on one of my ST1100s - the ABS and TCS lights just flashed when you took off (normally they go dark if all is well).
Turned out to be the 'reset' switches in the left fairing. You might get some good electronic contact cleaner and spray the computer contacts and give a good dose to both switches, working them a bit. When I did that, the problem went away for a while but came back. When I replaced both switches, that seems to have fixed the problem.