I have a 2006 c6 coupe. Yesterday I got in the car and backed out of the driveway and noticed the steering wheel was very loose and not firm at all. Once the car hit 40mph the steering firmed up like it was suppose to. I havent done any work on the car that may have damaged something, I checked the power steering fluid level and its full. It is somehow stuck in this loose, way to easy to turn mode, but when it hits 40mph it firms right up. Any ideas? Thanks everyone.

 

Have you checked your tire pressures lately?

 

There should be only 1 "mode" on your 2006, but the effort is designed to increase somewhat at higher speeds.

Is the wheel simply too easy to turn at low speed, or are you turning it but nothing happens?

 

Find an auto parts store that has a scanner that can read ABS codes. There could be an issue with your MagnaSteer subsystem. All Corvettes since 97 have had Magnasteer which adjusts steering resistance based on car speed. Magnasteer is controlled by the EBCM (why the scanner needs to be able to read ABS codes) and the steering rack.

Here is a description of how Magnasteer works:
Variable Effort Steering System Description and Operation
The Variable Effort Steering (VES) system, or MAGNASTEER II® varies the amount of effort required to steer the vehicle as vehicle speed changes or lateral acceleration occurs. At low speeds, the system provides minimal steering effort for easy turning and parking maneuvers. At high speeds, the system provides firmer steering (road feel) and directional stability. When the system senses lateral acceleration, steering becomes firmer to reduce oversteering. 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. The actuator adjusts the amount of power steering assist 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 Antilock Brake System (ABS) wheel speed sensor inputs to determine vehicle speed. When the EBCM senses vehicle speed, it commands a current to the actuator that is most appropriate for each speed. The system also uses inputs such as Handwheel position, wheelbase, understeer coefficient and steering ratio to calculate lateral acceleration. 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 circuitry to the actuator. Any malfunctions detected will cause the system to ramp to zero amps and steering will be assisted by hydraulics only.

Here is the diagnostic for the one fault code related to this subsystem:

Diagnostic Instructions
DTC Descriptor
DTC C0450: Steering Assist Control Solenoid/Motor/Actuator Circuit
Circuit/System Description
The variable effort steering (VES) system uses the electronic brake control module (EBCM) to control current to a bi-directional electromagnetic rotary actuator. The EBCM commands current from negative 3 amps to positive 3 amps to the actuator. At low speeds, less than approximately 24 km/h (15 mph), negative three amps of current is commanded, providing maximum assist to steering. As speed increases, increased (more positive) current is commanded, reaching zero amps at approximately 96 km/h (60 mph). The EBCM commands positive current only during steering input at higher speeds, based on the above inputs and the vehicle calibration, which creates steering resistance.
Conditions for Running the DTC
•
Ignition voltage between 10.5-17 volts

•
Off state test--Initial ignition ON, no engine RPM or vehicle speed present.
•
On state test--If off state test passes, engine RPM and vehicle speed present.




Conditions for Setting the DTC
The EBCM detects an open, short to ground, or short to voltage in the VES actuator or the actuator circuits.
Action Taken When the DTC Sets
•
DTC C0450 is stored in memory.

•
The driver information center (DIC) displays the SERVICE STEERING SYSTEM warning message.
•
The VES system is disabled for the remainder of the ignition cycle.





Conditions for Clearing the DTC
•
The condition for setting the DTC is no longer present.
•
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.



Diagnostic Aids
The vehicle may need to be driven to view full VES Actuator Commanded and Actuator Feedback Data parameters.
Circuit/System Testing
1. Ignition OFF, disconnect the VES actuator harness connector.
2. Measure for 0 volts between the variable effort steering actuator supply voltage circuit terminal A and ground.
⇒
If the voltage is greater than the specified range, test the variable effort steering actuator supply voltage circuit for short to voltage. If the circuit tests normal, replace the EBCM.
3. Ignition ON, measure for 12 volts between the variable effort steering actuator supply voltage circuit terminal A and ground.
⇒
If the voltage is less than the specified range, test the variable effort steering actuator supply voltage circuit for short to ground or open/high resistance. If the circuit tests normal, replace the EBCM.
4. Connect a test lamp between the variable effort steering actuator supply voltage circuit terminal A and the variable effort steering actuator control circuit terminal B at the VES actuator harness connector.
5. Using a scan tool, command the VES actuator ON. Verify the test lamp illuminates.
⇒
If the test lamp does not illuminate, test the variable effort steering actuator control circuit for open/high resistance. If the circuit tests normal, replace the EBCM.
6. If all circuits test normal, test or replace the VES actuator.
Component Testing
1. Ignition OFF, disconnect the VES actuator harness connector.
2. Measure for 5-10 ohms of resistance between the VES actuator terminals A and B.
⇒
If the resistance is outside the specified range, replace the VES actuator.
3. Measure for infinite ohms of resistance between each VES actuator terminal and the VES actuator housing.
⇒
If less than the specified range, replace the VES actuator.



This may not be the problem but it is easy to check yourself using a DVM.

Bill

 

Yes my tire pressure is good and yes it turns fine just way easier than it should. I feel a very noticeable firming when it hits 40mph. Bill the car wont throw a code if there is a malfunction like this? Because nothing has popped up thus far.

 

On my 09 I notice when at speeds above maybe 40MPH the steering is firmer in a right turn than it is in a left turn.

Anyone else notice this?

 

I have not noticed that on my car.
2009 Z51.