Today I got on my bike for a ride and noticed that the speedometer wasn't working (0km/h) and the red ABS warning light was on. I took it back to the garage and inspected the bike. The wheel speed sensor near the front brake caliper was fine, but when I followed the wiring up into the bike, one of the two wires was broken clean from the crimped bullet connectors. After soldering the wire back to the connector and covering it, the problem was fixed immediately.
There is an obviously a design fault with the wheel speed sensor wiring. The first 50cm of wiring from the sensor is quite strong since it is double insulated. However, the two wires become exposed and are connected to the wiring loom with flimsy bullet connectors. These two wires move back and forth every time you turn the handlebars, causing them to break from fatigue.