Cars just keep getting smarter all the time. Sensors are being used to monitor more and more functions, and to share information between vehicle systems that formerly were mute or didn’t communicate with one another. One such sensor is the steering position sensor. The sensor’s basic function is to monitor the driver’s steering inputs. This includes the angle of the steering wheel and/or the rate at which the driver is turning the wheel. The information may be used to vary hydraulic pressure in a variable assist power steering system, or by a stability control system to improve handling, braking and traction under changing driving conditions.

Early Applications
In the 1980s, automakers introduced the first generation of variable assist power steering systems. The simplest of these systems used a solenoid on the steering rack to reduce hydraulic power steering assist when the vehicle was traveling faster than a certain speed (typically above 20 to 25 mph). Reducing power assist as the speed increased improved road feel and steering stability. The only sensor input required for these systems was a vehicle speed sensor signal.

The more sophisticated variable assist power steering systems added a steering sensor to override the cutout solenoid when the driver made a sudden steering maneuver. The Ford Variable Assist Power Steering (VAPS) system on the 1988 Lincoln Continental and the Electronic ...