Specifications

Chassis Specialist : Electric Power Steering
Page 6
TORQUE SENSOR SIGNAL 1
TORQUE SENSOR SIGNAL 2
Snap shot of a 2004 Malibu Torque Sensor on a right turn
The compensating coil is used to buffer changes in the electrical current caused by temperature,
varying electrical loads and system voltage providing the detecting coil with a constant voltage with
which to accurately detect steering wheel movement. The detecting sensor is a dual analogue sensor
that uses a 5 volt reference and is valid between 0.25 and 4.75 volts. The sensor operates by having one
signal voltage reading high and the other signal voltage showing low. This gives a mirror effect, when
sensor 1 voltage is high then sensor 2 voltage will be low.
The steering wheel position sensor is used by the PSCM to determine when the steering wheel is in the
centre position. As the EPS system will try to give the driver the same “over centre feeling” and
provide the “return to centre” that a hydraulic system does, the PSCM has to know the centre position.
The sensor is an analogue triangle dual signal device that uses a 5 volt reference. The sensor readings
are valid between 0 and 5 volts but the sensor’s dual signals (Signal 1 and Signal 2) must be within 2.5
to 2.8 volts of each other when the steering wheel is turned. If the voltages are out of range the PSCM
will disable the power steering assist and set a DTC.