Abstract: A fail-safe system for an automotive suspension control system monitors inputs from one or more sensors monitoring vehicle driving conditions and producing sensor signals indicative of suspension control parameters, and operation of a controller. The fail-safe system performs fail-safe operation by which over-steering characteristics of the vehicle are prevented when malfunction of any of the sensors or of the controller is detected. In order to ensure prevention over-steering, the fail-safe system stiffens the suspension for driving wheels so that the damping characteristics at the driving wheels are stiffer than at the driven wheel.

Abstract: A suspension control system detects application of vehicular brakes to make the anti-dive suspension control active. During anti-dive suspension control, the vehicle height is continuously monitored to measure both the amplitude and rate of change of the vehicle height. If the height of the vehicle above the road surface changes by more than a predetermined vehicle height change criterion within a given period of time following application of the brakes, the suspension is ordered to become more stiff. This increase in stiffness suppresses the intensity of nose-dive during deceleration. Preferably, after a harder suspension is ordered, the suspension is held at the hardened level for a predetermined period of time and thereafter returned to the normal level.