The message is indicating a condition that traction is being lost, and the clicking under the hood may be a combination of brake modulation and/or torque reduction, to bring the data back into perspective. It could be one of several components delivering the faulty information to indicate a slip. Ideally, you would need to monitor the data, to pinpoint the culprit. What I have seen on other vehicles is a faulty wheel speed sensor, your vehicle has four of them. To best describe the condition, the signal from one of the sensors fluctuates, making the ABS/TC system think that a wheel is spinning. Since there is no brake switch input, it is deemed as a traction event. In contrast, if there was a brake switch input, then in theory three wheels would be slowing at a rate faster than one, and that would constitute an ABS event, and you may hear or feel similar sensations. In the ones that I have diagnosed, the problem usually occurred at slower speeds, and when the speed sensor data was plotted on a line graph, one would be increasing/decreasing speed, and causing a noticeable spike, thus causing the condition. It could be a faulty sensor, or even resistance in the circuit, created by corrosion, faulty connection, connector terminal fault, or wiring. This is just a possibility of one scenario.