The ABS light is intermittent on my Honda Shuttle (R Reg, UK spec), and it took a while to find out how to find out what is wrong. Most internet info said stick a paper clip in the terminal under the glove box. Close...but there are two blue terminal under there, both stored in a blue female housing. The one you need is the two pin one. Pull out of the housing (the housing is only for storage), and connect the two pins using a bent paper clip. Then turn the ignition on, but not the engine. The ABS light will then blink. There are two sets of blinks on my car, one long start blink, then a number of short one (count these), then a pause, then a number of long blinks - count those. This gives a two digit number, which is the fault code.
See this Honda Odyssey site (the USA version of Shuttle) for the fault code. This is a good site for Shuttle owners.
Fault Code Table
Mine appears to be 5-8 which is a left rear wheel lock. Info seems to indicate this means the sensors thought the wheel was locked i.e. not turning. Its probably just a grubby sensor, so will post results when I have time to investigate. The light is off at the moment, so won;t worry until the MOT is due - Note an ABS light on is an instant MOT fail, even if the brakes are working fine (albeit with no ABS)