Steering: Testing and Inspection

Power Steering Pressure Test





Test Equipment

Installing Test Equipment
To install the pressure test equipment:
Place a suitable drain tray below the PAS pump.
Install a hose clamp on the reservoir to pump hose prior to disconnecting any hoses, to avoid unnecessary loss of fluid.
Disconnect the hose from the PAS pump high pressure outlet.
Install the pump outlet to hose adapter (5). Do not omit the 'O' ring (9).
Connect the pump adapter to control valve hose (6) of the test equipment.
Install the adapter (4) in the high pressure hose previously removed from the pump outlet.
Connect the connector (3) of the test equipment hose (2) to the adapter (4).
Remove the hose clamp from the reservoir hose. Start the engine.

With the control valve (7) OPEN and the engine idling, the following system pressures may be checked:
During turning.
When the steering is held on full lock.
With the steering at rest.

WARNING: TO AVOID EXCESSIVE HEATING OF THE PAS PUMP, DO NOT CLOSE THE VALVE FOR LONGER THAN NECESSARY.

WARNING: DO NOT DRIVE THE VEHICLE WITH THE TEST EQUIPMENT INSTALLED.

With the control valve (7) CLOSED the pump maximum output pressure can be checked.


Removing Test Equipment
To remove the test equipment:
Install a hose clamp on the reservoir to pump hose.
Removing the test equipment is a reversal of the installation instructions.
Install a new 'O' ring (9) to the PAS pump high pressure outlet to hose connection.
Install the original hose to the PAS pump.
Remove the clamp from the reservoir to pump hose.
Top-up the reservoir fluid.
Bleed the PAS system.

Power Steering Control Module
As described above, the control of the valve is by varying the current which is applied to it. The current signal is provided by the Control Module which inputs a vehicle speed signal from the Instrument Cluster.
The microprocessor and associated algorithm within the module, provides maximum output current (854mA) when the vehicle is stationary-the valve will be held closed, providing very easy steering. The current progressively decreases towards zero (15mA) as the frequency of the speed signal from the Instrument Cluster increases-the valve will be opening in stages. Consequently, an increasing amount of hydraulic pressure is applied to the reaction piston, which increases the feel to the driver.

Refer to PDU User Guide
The PDU will diagnose all electrical components of the system,
Before changing a component, check fuse No. 12 (10A) in the driver's side fuse box on the fascia. However, if this fuse is faulty a number of other components will also fail to function.









Control Module Connections