Steering System - Variable Assist: Testing: Notes

NOTE: At 1000-1500 RPM, power steering pump pressure should be 1066-1138 psi (75-80 kg/cm² ) with fluid temperature at 122-140°F (50-60°C) and pressure gauge valve closed for no more than 15 seconds. If pressure is low, repair or replace pump.

A thorough visual inspection should precede all VAPS testing. See TROUBLE SHOOTING and WIRING DIAGRAM . An analog Volt-Ohmmeter (VOM) is needed to access VAPS test connector.

There is no warning light to signal driver about power steering control system problems. The control module does NOT store any fault codes. Trouble codes are accessed through VAPS test connector, below windshield wiper motor.

Information concerning possible problems can be gained through 3 specialized tests: KEY ON, ENGINE RUNNING TEST, CONTINUOUS MONITOR TEST and PINPOINT TESTS. These procedures test the system's integrity and processing capability. Tests also verify sensors and actuators operate properly.

Repair any mechanical fault before testing, or false diagnostic information may be obtained. Before going to PINPOINT TESTS, to avoid replacement of non-defective parts, complete, in order, the following tests:

Note location of 3-position slide switch on VAPS control module before entering diagnostics. See Fig 1 .

NOTE: If vehicle passes all phases of KEY ON, ENGINE RUNNING TEST and CONTINUOUS MONITOR TEST, the problem may be mechanical. When directed to PINPOINT TESTS, look carefully at wiring diagram. Any time a repair is made, KEY ON, ENGINE RUNNING TEST should be repeated.

Fig 1: Locating 3-Position Switch on VAPS Control Module

Courtesy of FORD MOTOR CO.