Matt Y

Hi technical gurus! My 2022 GLC 300 4MATIC has uneven steering resistance and I want to learn why. In most driving conditions, it is noticeably easier to turn left than right.

More info:

• The vehicle tracks straight when going and stopping.
• The steering feels centered.
• The electric power steering is clearly controlling resistance at all speeds.
• When turning right at most speeds, steering resistance begins almost immediately
• When turning left at most speeds, steering resistance begins after some amount of turning the wheel (not much, but enough to be noticeable)
• I've already had the steering module upgraded because of the known vibration issue

Hopefully useful context:

• I owned a 2019 BMW 330i with the same behavior. I had the dealer perform alignment, which they found to be unnecessary. No improvement. I hated it and sold the car.
• Then I owned a 2021 GLC 300 RWD with no such behavior that I could tell.
• Now I own a 2022 GLC 300 4MATIC with behavior described above. I suspect that some of all of these cars use the same Bosch system.

Thanks!

konigstiger

I assume MB did upgrade under factory warranty dictated by bulletin, service campaign, etc. Has dealer reached out to MB technical assistance at all and if not, request shop foreman or lead tech do so.

W205C43PFL

Sorry to hear that, any chance you can test drive another vehicle preferably the same model year as yours and similar spec, especially tires and see if you experience the same to confirm if it is normal or just your vehicle?

Matt Y

I did that with the 2019 BMW. Validation was not conclusive, partly because the BMW also had something like a dead spot in the center.
I sort of did that with the Mercedes, by having 2021 and 2022 models.

I was hoping that someone would know why it might feel like that.

Eventually I'll ask the [busy] service dept to weigh in, and maybe waste some more money on alignment.

W205C43PFL

FWIW, when I had a 2021 GLC loaner I never experienced something like you mentioned, hopefully a software update can change it?

CaliBenzDriver

> Issue statement:
-- Electrical steering wheel forces are unsymmetrical.

--You have eliminated uneven tire pressure, tire temperature and got expertly aligned wheel geometry.


​​​​​Hundreds of factors in a car affect its steering and road handling. It's easy to get no traction dealing with this type of issues.


> Long story short...:
1-- The steering rack module needs to be set in relation to steering wheel angles. (Straight wheels match the rach center and the zero degree sensor)

2-- The steering controller may provide unreliable data to rack over shared CAN.

3-- Overall this system is quite SAFE. It can gently disfunction when service is required.


The smart electric steering system has evolved to become sofisticated and difficult to fully learn. It is driven by 80Amps electrical power that's controlled by sensors and software.
The software can report a busy lists of errors except for what we need. You have to doctor your way through data.

The steering rack works with a sofisticated optical sensor located in the steering control module. By that I mean any fraction of steering angle change is sensed by a prismatic lens (like on a laser disc readers).

The electric steering rack input shaft has a torque sensor for the steering column shaft. This is a sort of legacy control used when CAN bus gets jammed.


The steering controll software is implemented to improve response behavior and interface with self-steering inputs.

> Hands On:
Specifically hold the car neutrally straight on zero degree center or try to return to preferred position.

Check the corresponding angle data in SCM when car is driving straight steering is "centered" - I am almost positive WIS has an awesome procedure to accomplish that precisely in 20mn.


- When alignment tie-rods get adjusted or rack gets swapped in a factory recall this may have been left non-adjusted to cut time.

- You can plug-in your iCarsoft/basic scanner to quickly retrieve data. Data is not hidden thanks to open standards.
✌️

The difference is significant:
This just makes the handling poor directly in the driver's hands... hard to ignore it!