ST1100 ABS / TCS fault finding.

[Bloxham]

Hi, I’ve got a 2000 ST1100 ABS/TCS purchased recently. The ABS warning lights are not working at start up and I need to fix this.
My question is, where is the location of the
ABS indicator relay that I can see on the wiring diagram ? This looks like a good place to start testing.
Without the ABS lights working, I can’t read the fault codes.
It could be that someone has disabled the lights due to an ABS fault but I need to start somewhere. (TCS lights working ok at ignition on, just no ABS lights which are 2 LEDs in the instrument panel).

 

[jfheath]

My question is, where is the location of the ABS indicator relay

I can't help with the relay location. I don't think there would be a relay just for those bulbs, and I cannot see one in the diagram. The wiring seems to be coming from the ignition control module and/or the ABS control unit. They will be turned on by relay or by the ignition switch - so if the bike fires up, then those bulbs should work, if they are plugged in.

The switch may also be disconnected. That double switch unit lifts out. Held in place by a slightly bent spring on each side (sorry - I sold my 1100AY 17 years ago so memory may not be 100% on this as well. It probably has wires permanently atatched - with conennectors buried further under the fairing. You can get the fairing off by lifting the switch out, turning it on its end and poking it back through the rectangular hole.



I see the two switches for TCS and ABS /TCS indicator - they are the ones positioned by your left knee. It appears that the two bulbs - 12 and 13 in the diagram - are easy to connect / disconnect - it shows them as a black and a red 2 pin mini connector. 11 - the TCS indicator light is shown as being connected with 2 bullet connectors. You are right - if ABS stops working, then to disguise the fact, the bulbs can be disconnected.

The braking system works perfectly well without ABS being armed, (alebeit without ABS) and it is not an MOT failure - as long as the brakes themselves work.

It won't help you with getting the bulbs working, but everything that I once knew about fault finding with the 2000 ABS CBS TCS ST1100 is documented here - including videos of showing retrieval of the fault codes - for when you do find them.

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

 

[ST1100Y]

Possible someone simply pulled the bulbs to "clear" the error warning?

Relays sit on the front cowl sub-frame, left and right of the headlight...

 

[jfheath]

Memory is coming back now....

If it is your ABS sensor that is faulty - typically that is the case - then the fault code will tell you nothing ! A fault code for the sensors can only register in the system if it was working and it then failed while riding. In other words - the bike has to have been started, rolled forwards a few metres at more than 6mph (or whatever it is) and the ABS light has to go out. Then if it fails, it can tell you which sensor has stopped working.

If it is the ABS modulator that is faulty - they whirr into life when you turn on the ignition. If they have a fault, they will be registered after that first start up cycle. You can put your hand on the rear one and feel that it is working. The front one is harder to get a finger to with the fairing in place. The relays for those are under the front cowl as @ST100Y said.

To find out which sensor is faulty - I discovered something which is documented in that link - and which I doubt you will see documented anywhere else. Quick precis: You clear the codes and then leave the bike in diagnosis mode and spin the wheels. if the sensor is working the ABS light blinks. If it isn't, it doesn't. Something like that. Read my write-up in the link. I wrote it just after I had finished diagnosing my problem at the time - and later transferred the writup to this site. So that write up is much more accurate than my memory.

 

[Bloxham]

Memory is coming back now....

If it is your ABS sensor that is faulty - typically that is the case - then the fault code will tell you nothing ! A fault code for the sensors can only register in the system if it was working and it then failed while riding. In other words - the bike has to have been started, rolled forwards a few metres at more than 6mph (or whatever it is) and the ABS light has to go out. Then if it fails, it can tell you which sensor has stopped working.

If it is the ABS modulator that is faulty - they whirr into life when you turn on the ignition. If they have a fault, they will be registered after that first start up cycle. You can put your hand on the rear one and feel that it is working. The front one is harder to get a finger to with the fairing in place. The relays for those are under the front cowl as @ST100Y said.

To find out which sensor is faulty - I discovered something which is documented in that link - and which I doubt you will see documented anywhere else. Quick precis: You clear the codes and then leave the bike in diagnosis mode and spin the wheels. if the sensor is working the ABS light blinks. If it isn't, it doesn't. Something like that. Read my write-up in the link. I wrote it just after I had finished diagnosing my problem at the time - and later transferred the writup to this site. So that write up is much more accurate than my memory.

Thanks for the info John & ST1100Y - this evening I took the screen & covers off to find both ABS LEDs missing. Luckily I have a spare ABS clocks unit so was able to fit the LEDs from that.
Now the lights are working, I've tried to read the fault codes but it does not look like any are stored, which is a bit odd. I'll try riding up the road when the snow has gone, also try that check of the wheel sensor signals.

 

[jfheath]

Copied and pasted from my link above.

Jfheath's trick to detect working sensors.

• Try to retrieve the problem code as before (yes I know you've done it already. Do it again).
• Clear the problem code (yes - even if there wasn't a fault recorded)
• Do NOT turn the ignition off.

At this point the lights look just like they are when you turn the ignition on - but this is not the case. Only if you have gone through the above procedure can the following test be carried out.

• Spin the wheel as fast as you can and watch the ABS warning light. If it flashes, the sensor is working. (nb - you will need a mirror or a friend to check this for the front wheel - the light only flashes while the wheel is in motion. The back wheel is easy, you can start the engine and slip it into gear)