A BRAKING SYSTEM

A braking system (110, 1110) operable to assess valve operation and a method including: an electronic control unit (132), a supply line (116, 1116) for connection to a pressurised fluid supply, a control line (124, 1124) for connection to a pressure demand, a modulator valve assembly (113, 1113) for controlling fluid supplied to one or more brake actuators (112, 1112), an electrically operable valve arrangement, which has a first state and a second state, wherein in the first state, the control line (124, 1124) is connected to the modulator valve assembly (113, 1113), and in the second state, the supply line (116, 11116) is connected to the modulator valve assembly (113, 1113), and a pressure sensor (128, 1128) positioned to monitor the pressure in the control line (124, 1124), wherein the electronic control unit (132) is operable to perform a testing cycle in which the electrically operable apply valve arrangement is moved to its second state, for a predetermined test pulse duration, and wherein the electronic control unit (132) is operable to monitor a pressure sensor signal from the pressure sensor (128, 1128) after the test pulse has been applied.