Brake Failure light - Again

[Wreford Miles]

Last time the symptoms were warming light on no ABS (tested by being able to lock the back wheel) and no speedo to start with but then working after a few miles - That was fixed by a new sensor in the rear hub.


This time I’m pulling away from some lights and the traction control kicks in ( bit of a nuisance as I was doing one of those quick starts from the wrong lane and needed to cut across everyone) anyway I’m thinking what was that all about it was a prompt getaway but nothing that should have induced the traction control when I notice the brake fail light and traction control triangle lights.

The speedo was working, so I stopped and restarted and this time no triangle but the brake fail light is still on. I’ve also no abs and the speedo is working.

Just wheeled out the garage to check again and it’s a warning light, no abs and the speedo is working so I’m thinking this is not like before.

Any pointers

2013 Hexhead GSA one of the very last ones

Cheers

Wreford

 

[Tractors are go]

Get someone to read fault codes on a 911?

First thought is what do they all have in common ?

Sensor or wiring.

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[Pukmeister]

Traction control intervenes when it detects wheelspin. Its a pretty basic system with no lean angle sensors etc, I think it compares front and rear wheel speeds versus throttle position and if it senses a large difference it chops the ignition/injection.

Maybe the fault lies in either the rear, or possibly the front wheel speed sensor. Check the gap between the front ABS sensor at its reluctor ring isn't excessive or fouled with dirt build up. Maybe pop out the rear ABS sensor from the final drive housing and check for a 'christmas tree'-like build up of fine metal wear particles on it. (tiny torx screw, clean it out before inserting the torx bit to prevent it rounding off internally). Also check the rear ABS sensor cable connector beneath the seat is securely fitted and the cable itself is not frayed or damaged along its length, especially where it is clipped to the FD and paralever arm.

 

[Wreford Miles]

Traction control intervenes when it detects wheelspin. Its a pretty basic system with no lean angle sensors etc, I think it compares front and rear wheel speeds versus throttle position and if it senses a large difference it chops the ignition/injection.

Maybe the fault lies in either the rear, or possibly the front wheel speed sensor. Check the gap between the front ABS sensor at its reluctor ring isn't excessive or fouled with dirt build up. Maybe pop out the rear ABS sensor from the final drive housing and check for a 'christmas tree'-like build up of fine metal wear particles on it. (tiny torx screw, clean it out before inserting the torx bit to prevent it rounding off internally). Also check the rear ABS sensor cable connector beneath the seat is securely fitted and the cable itself is not frayed or damaged along its length, especially where it is clipped to the FD and paralever arm.

Thank you....I did not have time to check It over yesterday, but mulling it over my deductions are:

Traction control blip happened first so must be related to that - Which means sensors and not something in the braking system
Speedo still works from the off - Which suggests the rear sensor is OK

I'l start by looking at the front sensors

 

[seahorse]

I am just down the road from you if you want me to check with a GS911.

 

[Pukmeister]

Wreford, I believe the system can use the front ABS sensor for speedo if the rear fails.

I can't prove that, but when my rear sensor played up and alerted me to an ABS problem (with swarf build up) my speedo fluttered at first then stopped for about a mile then suddenly burst into life as if the software had switched to the front sensor.

I wouldn't discount the rear sensor check just because the speedo still works.

 

[Coppertop]

I had something similar happen to me yesterday. Pulled away from traffic lights in the rain after filtering. Didn't see traction control kick in but who knows.
Notice my brake light warning is on, pull over and notice I've no tail light whatsoever. However when I turned off the bike and turned it back on the tail light was back on. Should I be concerned? Never noticed it happening before. TC RT.

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[Wreford Miles]

Findings of the not to technical... I reckon it’s the front sensor

Tried to remove the front sensor this morning, took the bolt out but it was not moving so gave it a wipe and wiggled the wires and went for a ride and all seemed OK, but!

After a few miles the bike would start to hesitate a bit like traction control cutting in and I noticed the speedo was fluttering. Pukka I believe you are right rear is the speedo but if that fails after a few miles the front takes over so I’m thinking it must be the front because a wipe and a wiggle fixed it but a fluttering speedo makes me think rear.

Anyway the hesitation is getting worse and occasionally the traction control triangle was now also coming on and then it stayed on and the brake fail light came on and the good bit was....the hesitation stopped and the speedo stopped fluttering

So having now bought the bacon from Nobbys farm shop near Leighton buzzard, the best streaky ever, and on my way home I wait until I’m nearly Home (pushing distance) stop and wiggle the wire to the front sensor start the bike again and hey ho no warning lights, get Home put the bike engine running on the side stand to open the gate (wife was out) and the warning lights are back on.

Conclusion front sensor or maybe if I’m lucky a connection that needs cleaning at the bike end of the wire but I doubt it - So I’m guessing it will be a new sensor c£80 fix

Seahorse thanks for the 911 offer I may take you up on that

 

[Pukmeister]

Wreford, try cleaning the rear sensor anyway before shelling out, just in case.


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[Santa-2512]

I tried changing from my rear sensor to my front sensor,

The speedo was way out 80mph at about 40mph - i put it down to having a servoectomy

I was going to remove my front sensor, but unless i get a hammer and punch on it, it aint moving lol

 

[Tractors are go]

Try heating around sensor and then spraying liquid nitrogen ( or wart/Verruca spray) on it, thermal shock often works.

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[Wreford Miles]

I tried changing from my rear sensor to my front sensor,

The speedo was way out 80mph at about 40mph - i put it down to having a servoectomy

I was going to remove my front sensor, but unless i get a hammer and punch on it, it aint moving lol

Mine seems stuck in, did not have time to investigate fully but it seems it’s just the one resting screw.

 

[Bendy toy]

When the rear sensor fails, the bike will run fine but you get the "brake failure" red warning and no speedo for the first few minutes of riding. The speedo will eventually wake up when the system switches to reading speed from the front sensor. You'll have no ABS until both sensors are working properly.

The traction control works on mud but it's useless on cold wet roads on cold tyres when a simple right turn with slightly too much throttle will low-side the bike.