138 Driving and operatingABS starts to regulate brake pressureas soon as a wheel shows a tendencyto lock. The vehicle remainssteerable, even during hard braking.ABS control is made apparentthrough a pulse in the brake pedaland the noise of the regulationprocess.For optimum braking, keep the brakepedal fully depressed throughout thebraking process, despite the fact thatthe pedal is pulsating. Do not reducethe pressure on the pedal.Control indicator u 3 88.FaultIf control indicators u and Ailluminate with the messages CHECKABS and CHECK ESP in the DriverInformation Centre (DIC), there is afault in the ABS. The brake systemremains operational but without ABSregulation.9 WarningIf there is a fault in the ABS, thewheels may be liable to lock dueto braking that is heavier thannormal. The advantages of ABSare no longer available. Duringhard braking, the vehicle can nolonger be steered and mayswerve.If control indicators u, A, R andC illuminate, the ABS and ESP aredeactivated and the messageBRAKING FAULT is shown in theDIC. Seek the assistance of aworkshop.Have the cause of the fault remediedby a workshop.Parking brake9 WarningAlways apply parking brake firmlywithout operating the releasebutton, and apply as firmly aspossible on a downhill or uphillslope.To release the parking brake, pullthe lever up slightly, press therelease button and fully lower thelever.To reduce the operating forces ofthe parking brake, depress thebrake pedal at the same time.
