ABS light

paulr4 · L Plate Warrior Joined: 04 Oct 2021 Karma :

I recently bought a 2004 Honda CBF500, my first bike with ABS. On getting it home and reading the manual, I see the ABS light is supposed to light up on ignition and then go out above 10mph or so. Might doesn't light up, ever.

I checked the fuses, in case they'd been removed to mask a problem. The 3 in the ABS fusebox under the right-hand side panel are all present and correct.

Delving deeper into the bike I was able to disconnect the rear sensor and measured a resistance of 6.7MOhms across it, much higher than some light googling suggests it should be. However, the symptom of a bad sensor should be a flashing warning light, not no light at all. The voltage from the controller side of the sensor connector was about 2.5V.

Can anyone advise what to try next?

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

See if the bulb is blown.
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xX-Alex-Xx · World Chat Champion Joined: 12 Sep 2019 Karma :

Does the ABS actually work? Pretty easy to try to lock the rear to test.
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weasley · World Chat Champion Joined: 16 Oct 2010 Karma :

Someone may have removed the ABS bulb to mask a problem.
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paulr4 · L Plate Warrior Joined: 04 Oct 2021 Karma :

I'll dismantle the dash next chance I get to see if the bulb is the issue. As for testing it, I did try stamping on the rear brake but it felt a bit squashy and couldn't get the rear wheel to lock up. Perhaps that's another problem I should be looking at! Confused

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

My bikes have LED lamps so a bulb issue would be unlikely LED are more reliable.
Rather than a bulb blown it may be a wire broken or a plug pulled.
Normally, ABS are designed to be very robust and should auto/self-test when ignition is switched on.
The ABS lamp should continue to flash until the wheel sensors are detected boy moving the bike to rotate the wheels 1 turn.
It probably needs a Honda tool or a tool that can read Honda to diagnose that fault.
The brake should still work but depending on the system the ABS being disconnected to put the lamp out is serious. It may not make the brake fail but it could let full pump pressure onto the brake when you pull the lever. Sudden uncontrollable braking is risky.
Mixed with winter roads and Cooncil grit.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.