When the lights come on for the ABS - the first thing I do is to go into the workshop for it to be checked. The classic symptoms are as what you described and the solution varies in part.
The most common solution when this happens to the 124 is to check the ABS sensor - sometimes the sensor is dirty and needs a clean, or sometimes the sensor wires are a suspect.
The OVP rarely has a hand in this.
Its still safe to drive for now but don't do any hard driving on grass areas or wet surfaces.
126 tailed by a 203, 129 leading the pack.