Variable Effort Steering light turns on intermittently?

JEFF HERMAN

MEMBER
2005 PONTIAC GRAND PRIX
3.8L
V6
2WD
AUTOMATIC
383,000 MILES

Service variable effort steering light intermittent on center console. Also, Service ABS, traction off, and speed sensor lights on intermittently. Newer rack, no fluid leak. No noticeable effect on steering. Rear tires wearing unevenly. Going to run code to see which speed sensor. Also checking wiring harness to sensors, wheel bearing/hub assemblies, reluctor rings. Not sure if sensor is separate from hub. If it is maybe clean it. Would worn struts trigger these lights? Any other ideas which direction to go?

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,935 POSTS

It sounds like the Magnasteer actuator is out on the rack and pinion, here is a wiring diagram so you can see how the system works, also I would check the ABS motor fuse #31 under the hood. This guide can help?

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Variable Effort Steering System Description and Operation
The Variable Effort Steering (VES) system or MAGNASTEER Varies the amount of effort required to steer the vehicle as vehicle speed changes. At low speeds, the system provides minimal steering effort for easy turning and parking Maneuvers. Steering effort is increased at higher speeds to provide firmer steering (road feel) and directional stability. The Electronic Brake Control Module (EBCM) controls a bi-directional magnetic rotary actuator located in the steering rack and pinion. The EBCM varies the steering assist by adjusting the current flow through the actuator to achieve a given level of effort to steer the vehicle. The VES system accomplishes this by adding or subtracting torque on the input shaft to the rack and pinion. The main component of the system is an electromagnetic actuator, which consists of a multiple-pole ring-style permanent magnet, a pole piece, and an electromagnetic coil assembly. The VES system uses the ABS wheel speed sensor inputs to determine vehicle speed. When the EBCM senses wheel speed, it commands a current to the VES actuator that is most appropriate for each speed. The EBCM commands current from negative two amps to positive three amps to the actuator, which is polarized. At low speeds, a negative current is commanded, which assists steering. At medium speeds no current is commanded and steering is assisted by hydraulics only. At high speeds, a positive current is commanded, which creates steering resistance. Ignition voltage and ground are provided through the EBCM. The EBCM has the ability to detect malfunctions in the actuator or the circuits to the actuator. Any malfunctions detected will cause the system to ramp to zero amps and steering will be assisted by hydraulics only and setting a DTC.

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