Power Steering System Description & Operation (EPS): Notes

2009 Chevrolet Tahoe Base, 4.8 CSECTION Notes
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The 42-volt rack & pinion electric power steering (EPS) system reduces the amount of effort needed to steer the vehicle using the power steering control module (PSCM) to control the power steering motor to maneuver the steering gear. The PSCM also uses a combination of the torque sensor, motor rotational sensor, 42-volt circuit, battery voltage circuit and serial data circuit to perform the system functions. The PSCM monitors vehicle speed from the engine control module (ECM) via the serial data circuit to determine the amount of steering assist needed to steer the vehicle. At low speeds more assist is provided for easy turning during parking maneuvers. At higher speeds less assist is provided for improved road feel and directional stability.

The EPS system consists of the following components:

  • The PSCM
  • The power steering motor
  • The power steering motor rotational sensor
  • The torque sensor
  • The steering gear (rack and pinion)
  • The accessory power module (APM)

The PSCM and power steering motor are both serviced separately. The power steering motor is serviced separately from the steering gear; however the power steering motor rotational sensor is serviced as part of the steering motor. The torque sensor is integrated with the steering gear pinion and is serviced as part of the steering gear.

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.