Hi wolfgang,
I disassembled the pump, cleaned the coals, reassembled everything and the ABS fault has disappeared. Until when ?
I wonder if the problem is not the coals housing which are in stamped steel and folded and thus deformable. As they are fixed on a deformable plastic flange it is probable that it is sufficient to pinch coal. This possibility is compounded by the fact that the engine develops high torque to actuate the pump pistons.
Finally we'll see.
Jean-Claude