Speed Sensor Failure?

Discussion in 'Bonneville' started by Jet City, Sep 4, 2023.

  1. Jet City

    Jet City Noble Member

    Sep 24, 2018
    522
    343
    Seattle, Washington USA
    I have a 2018 Competition Green Bonneville T120. Terrific bike.

    A couple of months ago the dash threw up the check engine light, the ABS light, and the traction control light. See pic.

    I plugged in my OBD2 and it gave me the code for a speed sensor fail.

    This makes sense; the ABS and the TC need the speed sensor readings in order to work. My cruise control still works, and I assume that means that the front wheel speed sensor is fine (I’m guessing that the CC uses the front wheel sensor, but I don’t know that) and the rear is giving no signal.

    Has anyone else had this issue?

    Is it as simple as replacing the rear wheel speed sensor? Just it just need to be cleaned or something? Hard to believe that this part would fail.

    Thanks, everyone. Appreciate any advice and am curious to know if anyone else has had this issue.

    IMG_8925.jpeg
     
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  2. TRIPLE X

    TRIPLE X Senior Member

    Sep 1, 2021
    357
    113
    Downham Market, Norfolk
    I would first check that both front and rear perforated pulser rings and sensors are clean and undamaged. Check that the rings are not warped by spinning the wheels and check the air gap measurement as specified in the Service Manual.
     
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  3. Eldon

    Eldon Elite Member

    Nov 14, 2018
    6,302
    800
    North Yorkshire
    Does the issue coincide with a tyre change?

    The ring could've been damaged as @TRIPLE X mentions so it's worth checking the runout in situ.
     
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  4. andyc1

    andyc1 Lunarville 7, Airlock 3

    Feb 4, 2017
    2,927
    1,000
    N. Ireland
    Don't go near them with anything magnetic, I once put a magnetic torch on a break disc which stopped the ABS working. Maybe thats what happened? The discs are demagnetised at the factory to prevent this.
     
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  5. Jet City

    Jet City Noble Member

    Sep 24, 2018
    522
    343
    Seattle, Washington USA
    Thanks, y’all. I appreciate the feedback. And I didn’t know about the magnetic thing.

    No tire change happened (nor did I take the rear wheel off for any reason).

    I did check the clearance on the rear sensor; it is not touching the ring. I thought that might be it, but no.

    The factory minimum clearance is 0.4mm, it looks right.

    I’m okay with replacing the sensor, just not convinced that’s the problem.
     
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  6. RickM46

    RickM46 Active Member

    Oct 12, 2023
    55
    28
    US
    Any news?
     
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  7. Jet City

    Jet City Noble Member

    Sep 24, 2018
    522
    343
    Seattle, Washington USA
    I replaced the rear wheel sensor, which fixed exactly nothing.

    Triumph RAT here in the US has a thread going on this, tho. A couple of members there have this problem and it’s been traced to the wiring harness. Apparently the sensors are fine, the discontinuity is in the wiring between the sensor plug and the ECU.

    Posters on that forum spliced a new wire and job done. So now I need to go out to the garage and try it myself.
     
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  8. nickjaxe

    nickjaxe Active Member

    Sep 2, 2020
    64
    28
    Cheshire UK
    Old post this....did you sort it.....did it fail after maybe you took the bolt out of the rear sensor.....there is a washer its only fitted in one position.....its a spacer not really a washer.....if its just fitted behind the bold head the sensor will prob contact the brake rotor and bugger the sensor.

    Be warned people.
     
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  9. RickM46

    RickM46 Active Member

    Oct 12, 2023
    55
    28
    US
    Still, any more news?
     
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