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Description & Operation

WARNING: This page is about a different car, the 1992 Pontiac Bonneville, 1992 Oldsmobile Ninety-Eight, and 1992 Buick Park Avenue. However, it is still accessible from the selected car via links, so may be relevant.

Based on vehicle speed, Variable Effort Steering (VES) system, or Two-Flow Electronic (TFE) steering system, controls amount of power steering pump pressure applied to steering gear.

At speeds of about 20 MPH or less, pump pressure is increased, resulting in easier turning of the steering wheel. At speeds of about 20 MPH or more, pump pressure is decreased, resulting in more difficult turning of the steering wheel. This increased steering effort at greater speeds provides a firmer steering (road) feel.

The VES system consists of a Multi-Function Chime (MFC) module, Powertrain Control Module (PCM) and TFE actuator (or electronic variable orifice actuator). PCM receives a signal from the vehicle speed sensor. Based on this signal, PCM provides a ground for vehicle speed sensor circuit of MFC. Pump pressure is increased when MFC grounds the TFE actuator under the following conditions:

TFE SYSTEM ELECTRICAL COMPONENT LOCATIONS

Component Location
Fuse No. 5 Near Right Kick Panel, In Relay Center
MFC Module Behind Instrument Panel, To Right Of Steering Column Support
PCM Near Right Kick Panel
TFE Actuator On Power Steering Pump, At Pressure Outlet