Heavy Steering Low Speeds - 2006 W221

[Barrys320]

Hi,

I need a bit of help trying to diagnose a steering fault I have on my 06 S320, W221.

I have no warning lights on the car, but am experiencing heavy steering on my car when turning at lower speeds. I have had it with the dealer and they can't seem to find a problem.

They checked the belts, no leaks anywhere and they don't think it's the power steering pump.

It seems like the car is confused and is over compensating (hugely) at low speeds, when it should only do this at high speed with the speed sensitive steering.

The steering is perfect as it should be with handbrake on and at low speeds when you drive away initially, but try turning it at low RPM at say 15-20 mph on anything like a 90 degree turn and the wheel stiffens up and you need two hands to try turn the wheel.

I've owned the car for two years and know how it drives, but the dealer said there is no problem with the car, but there definitely is, it wasn't doing this a few weeks ago and it is taking two hands to turn the wheel, as if the power steering isn't working at all.

The car had a brand new steering rack 9 months ago, and recently I had the steering wheel replaced for a wooden wheel. As much as this problem started after the wooden wheel was fitted, I don't think it could be connected.

Any ideas, as the garage doesn't know and I'm worried that I'll do more damage by continuing to drive it.

Maybe someone else has had a similar problem that might be able to help a bit?

Thanks for any help!!

 

[television]

The SPS is operated from the ESP module, I wonder if they know this and know where to look, it purely sends a signal to a valve in the power steering rack, slowly opening as the car goes faster- I would ask them the look at the ESP on STAR

 

[Barrys320]

They said they ran it on The Star machine but found no fault codes showing at all, hence the bit of mystery with it.

 

[television]

They said they ran it on The Star machine but found no fault codes showing at all, hence the bit of mystery with it.

Thats just no use in doing that, they need to go to the ESP circuits and reprogram things in the circuit, something may have lost some coding, and this will not show up as a fault.

They cannot just pass it by as OK,, you know your car, I have the 2 door version and you can turn the wheel with one hand when parking. There are also known faults that they have access to.

 

[Barrys320]

Thanks for the advice. Sorry for being stupid, but what is SPS?

 

[television]

Speed sensitive power steering.

 

[Barrys320]

Brilliant thanks a lot for your help

 

[Barrys320]

I noticed something today on the car after I read another similar post. I switched the car into sport mode today from default comfort and when I did, the heavy steering issue completely disappeared.

I drove to work in comfort and the car was very heavy at certain notable corners and points on the road, but on the same route home in sport mode, I could have driven back with the palm of my hand the steering was so different.

Does this point to anything from any more experienced posters?

 

[television]

I would have said a speed sensor, possible miss read, locked up, try it again in the C mode.

 

[Barrys320]

Thanks for the advice Malcolm. I had it in sport all day today and it ran perfect. I'll switch back to comfort in the morning and see what happens.

 

[MercMart0802]

What happened?

 

[abazem]

I am having a similar issue on my w211. The steering is soft when running in Sport or S mode but on Comfort or C mode it feels heavy especially when parking in tight spots.
Any help will be greatly appreciated.