The vehicle may be equipped with a stability control system which helps maintain direction control if the tyres lose grip integrating the ABS functions. See E7020 ABS The system in question is known as ESP (Electronic Stability Program) and acts by intervening on the engine torque and braking the wheels in a differentiated manner, helping to restore the vehicle to the correct trajectory if there is a loss in grip.The function is performed by the ABS control unit which, on the de-luxe version, also implements the ASR (Anti Slip Regulation), MSR (adjustment of engine braking torque), Hill Holder, HBA (Hydraulic Brake Assist) and obviously ESP functions.The ESP system intervenes on the engine and on the brakes, producing a stabilizing torque when the ABS sensors detect conditions that could cause the vehicle to slip.The function is carried out with the help of two dedicated sensors: the yaw sensor and the steering sensor.The former measures the rotation of the vehicle around the vertical axis and the lateral acceleration due to centrifugal force, whilst the latter measures the rotation angle of the steering, in other words it detects the driver''s desired direction of travel.By analysing this information the system analyses the actual movement of the vehicle adapting the supply of power to the engine to restore vehicle stability conditions. If this is not sufficient, the system intervenes by braking the individual wheels in a differentiated manner. This action causes a rotation moment opposed to the rotation produced by the skidding so that, within the physical limits, the vehicle is rebalanced and restored to the correct driving position.The intervention of the ESP is signalled by a dedicated warning light flashing in the instrument panel, thereby informing the driver that the vehicle is in critical stability and grip conditions.The Hill Holder function facilitates setting off on a hill: during take off the ESP system control unit maintains the braking pressure at the wheels until the engine torque required for departure is reached or for a maximum of 2 seconds, allowing your right foot to be moved easily from the brake pedal to the accelerator.When 2 seconds have elapsed, without any departure having taken place, the system is automatically deactivated, gradually releasing the braking pressure.The Hill Holder function is automatically activated in two situations:- on an incline, with the vehicle stationary on a road with a gradient of more than 5%, engine on, clutch and brake pedals pressed and gearbox in neutral or gear other than reverse engaged;- downhill, with the vehicle stationary on a road with a gradient of more than 5%, engine on, clutch and brake pedals pressed and reverse gear engaged.This function is carried out with the help of a longitudinal acceleration sensor incorporated in the yaw sensor.The Brake Assist system recognizes emergency braking (on the basis of the brake pedal activation speed) and guarantees an increase in hydraulic braking pressure supporting the driver allowing faster and more powerful intervention of the braking system.The function is therefore an important aid for the driver in emergency braking situations where the application speed on the brake pedal is high and maintenance load is poor.The ASR system (AntiSlip Regulator) is a traction control system for the vehicle which intervenes automatically if one or both of the drive wheels is slipping.If the slipping is caused by the transmission of excessive power, the system cuts in, with the co-operation of the engine management control unit, to reduce engine power output. If, on the other hand, the slipping is detected at one wheel only, the system cuts in to brake the slipping wheel only by means of the wheel''s modulating solenoid valve.The ASR comes on automatically whenever the engine is started. The ASR can be turned off and then turned back on again whilst driving by pressing the button located in the centre control panel.The switching off is shown by the LED in the actual switch coming on together with a message shown in the multifunction display, where present. If the ASR is switched off when driving, it is automatically switched on again when the vehicle is started up.The MSR system (engine drive regulator) is an integral part of the ASR, that intervenes, if there is a sudden change to a lower gear, supplying torque to the engine, thereby preventing excessive drive at the drive wheels which, especially in poor grip conditions, could lead to a loss in stability of the vehicle.For more details See descriptions 3350 TRACTION CONTROL If there is a problem with the ESP/ ASR / Hill Holder systems, the warning light in the instrument panel comes on constantly together with the display of the message in the multifunctional display, if present. If the ESP is activated whilst driving the warning light flashes until it switches off.