Component Description

The MAGNASTEER(R) system is made up of four components.
The four components are:
^ The Electronic Brake Traction Control Module (EBTCM).
^ The MAGNASTEER(R) actuator.
^ The Power Rack Gear.
^ The Power Steering Pump.

ELECTRONIC BRAKE TRACTION CONTROL MODULE (EBTCM)
The MAGNASTEER(R) system has software contained in Electronic Brake Traction Control Module (EBTCM). The EBTCM processes vehicle speed information from the ABS wheel speed sensors to provide a control signal to the MAGNASTEER(R) actuator located in the power steering gear.

If a malfunction occurs a Diagnostic Trouble Code (DTC) is stored in the EBTCM for the MAGNASTEER(R). No warning lamp will come ON during the malfunction. When a malfunction occurs, the DTC can be retrieved using a scan tool. If a MAGNASTEER(R) DTC exists, a difference in power steering effort may be felt. Normal ABS/TCS functions will remain active. Refer to DIAGNOSIS for more information.

ACTUATOR (MAGNASTEER(R))
The MAGNASTEER(R) actuator is an integral part of the power steering gear. The MAGNASTEER(R) actuator consists of the following:
^ A rotary valve.
^ A permanent magnet that is attached to the input shaft of the rotary valve.
^ Two pole pieces that are attached to the output side of the valve (the pinion).
^ An electromagnetic coil mounted in the gear housing

When the coil is energized, a magnetic field is formed between the permanent magnet and the pole pieces, which increases the torque on the input shaft to the steering gear. The EBTCM controls the current flow to the coil. As the vehicle speed increases, the EBTCM increases the current flow resulting in an increase in steering effort.

Other power steering system components, while specially modified for use with MAGNASTEER(R), are similar to non-MAGNASTEER(R) power steering components.

POWER STEERING GEAR
The design of the MAGNASTEER(R) power rack and pinion assembly is the same for a non-MAGNASTEER(R) system except for valve machining differences. Steering wheel movement transfers to the pinion. The pinion moves the rack left or right by meshing pinion and rack teeth. The force transmits through the tie rod ends and steering knuckles to turn the wheels.

The power rack and pinion steering system has a rotary control valve. The rotary control valve directs hydraulic fluid from the power steering pump of the two sides of the rack piston. The piston attaches to the rack. The attached piston uses hydraulic pressure to move the rack left or right. The rotary control valve regulates the amount of effort by responding to the driver's torque input.

Manual control is maintained when hydraulic assist is not available. More steering effort is required with manual control.

POWER STEERING PUMP
A constant displacement vane type pump provides hydraulic pressure and flow for the steering system. The pump is belt driven by the power steering pump and engine crankshaft pulleys. The opening at the rear of the pump housing contains:
^ The pump ring
^ The pressure plate
^ The thrust plate
^ The rotor
^ The vanes
^ The end plate

The pump housing side contains the pressure line fitting. The pressure relief valve inside the flow control valve limits the pump pressure.