Diagnosing ABS problems on a 2007 Honda CBF500 motorbike

Question

My bike is a CBF500 ABS that was first registered 2007 in the Netherlands and later exported to Germany, where I bought it in 2016.

Last year in autumn the ABS indicator light started to blink, and the ABS did not work anymore. I brought the bike to a certified Honda garage. They said the error code indicated an electrical failure, and that they had fixed it by cleaning the electrical connections to the sensors.

After that the ABS worked for two days before the indicator light show up permanently and the ABS failed again. I did not get a refund for the 200 Euro socket cleaning job, so I looked for another garage, which then suggested that they would start switching parts until the ABS worked again. Each ABS sensor comes at 275 Euro, the main unit at 750 Euro (plus VAT and work time), so randomly changing parts seems like a rather expensive way to diagnose the problem.

At this point I am not instilled with huge confidence when it comes to Honda mechanics. I wonder if there is a way to narrow down the problem a bit before I go to yet another mechanic. I will not try to fix this myself, but it might at least help that I do not feel ripped off when they suggest yet another expensive fix.

That the ABS temporarily worked when they fiddled with the plugs seems to suggest that there might be a connection problem, maybe a broken wire between sensor and main unit. I wonder if there is a way to test this.

Obviously I googled first before asking here, but some answers suggested that simply applying the prongs of a multimeter to each end of the wire would be enough, while others said this would be a hugely complicated process and not something I could do myself. I am not the worst hobby mechanic in the world, but for some reason I am unable to understand how electricity works, so I could use a little help here. Also the CBF moniker is used for several models, and most answers refer to the 2015 model which seems to have a standard diagnostics port that my model lacks.

Answer 1

So, your plan to test the wiring is basically fine, just takes patience and care!

If you gently move the wiring and it starts working - that can help you narrow down the problem. It could be a break in the wire or even it has rubbed and is shorting out on the clip or frame somewhere.

If you can get the wiring diagram and the workshop manual, then once you have tested the wiring, you can follow some or all of the testing procedures for the abs - do you have a code reader? Sorry, just seen no diag port...

Do you have any friends (on bikes or not) who are "happy" with electrics? They may be happy to help.

Answer 2

Here's a Link to an Article and Video by FamilyHandyman on checking an alternator with a Multimeter

You're looking for a steady number. The digit farthest to the right (generally the hundreds-place on most basic meters) may fluctuate +/- 1-2, but you should not see anything more drastic than that. Ensure that your meter probes are stable and have a good connection with the terminals, as this can cause drastic fluctuations if connection is not maintained.

As you've already read, yes... The rabbit hole continues further... But you can start with the procedure outlined above.

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Here is a Guide for a CBF1000 of the same era which will outline more specific information regarding the Charging System more closely related to your bike.

That guide also mentions that there is a ABS/FI Fuse. Assumingly the bike would not run if the Fuel Injection was on the same fuse as the ABS, but it would be worth checking your Owners Manual to determine where the ABS fuse is, removing it for visual inspection, and checking it with a multimeter to be certain it is indeed good.

Here's a YouTube video on testing a Fuse with a Multimeter

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Here's guide for Harley's Pre-Alternator Era

Here's a guide for Harley's running Alternators, like your Honda

It's obvious that Harley's and Honda's are not going to share the same specifications, but these articles help to explain, in detail, the point of the procedure, which I feel will make you more comfortable.

I hope this helps.

Answer 3

I gave in and brought the bike to a proper mechanic.

Apparently some paint judiciously applied by the previous owner had hidden a spot of corrosion that only got worse while I rode the bike. It affected the rear ABS sensor, and the part of the Chassis (if that's the right word) the sensor was mounted on. If I understood correctly that's the same part that holds the caliper. The repair would require a lot of replacement parts.

Basically, the bike is a write-off. In it's current state it's also a death trap, so I got lucky here.