Light Steering Mystery...

[piggasinnaris]

Hello all.

I'm trying to track down a mysterious issue on my car and so far had no luck.

Last 2 or 3 weeks when driving, I randomly get incredible 'lightness' on the steering wheel. No resistance or weight to the wheel when handing it, almost as light as if the wheels were off the road. It only happens for a split second. This has happened numerous times but the two specific moments I remember - coming to a dead stop at lights, stopped, wheel was so light it was almost floppy. Second time was doing about 50mph on a straight road, steered a little bit to avoid a drain cover and again felt like no resistance.

I've sort of ruled out the 'could it be the road surface' aspect as it's happening randomly everywhere I go, and not repeating in the same places (i.e. my street where I live etc) at the same time.

My initial theories, investigations and results:

• Steering angle sensor in the PAS overcompensating - checked obdeleven for codes, nothing. Live data seemed fine.
• Wheel speed sensor giving erroneous data - I previously snapped off a wire on a wheel speed sensor and suspected it might be this playing up, feeding back inconsistent data to the car. Again looked in obdeleven and viewed live data, looked fine.
• Track rod ends - I did some suspension work about 3 months ago and the one thing I didn't touch was the track rod ends. Thought maybe heat cycles etc loosened them up. But I jacked the car up and checked, feel absolutely fine, and I just had an MOT about 3 weeks ago so would imagine they'd have noticed that if so.
• Tyres - This is what I'm suspecting most at this point. My tyres are absolutely fine tread-wise (4mm left) but I did notice some wear on the edges, both sides, moreso than the middle. Tyre pressures are correct and alignment was done last year. (Attached is a picture where someone pointed out they look a bit worn on the edges)

Any other suggestions or ideas, has this happened to you?

2016 Leon FR Tech 3dr, 184 diesel, DSG. 91k miles. MOT'd last month.

 

[nd-photo.nl]

What drive mode are you using? My Cupra has 2/3 different modes if I remember correctly.

- Is it possible to "force" or replicate the behaviour?
- Doest it actually steer when it feels light?

 

[piggasinnaris]

What drive mode are you using? My Cupra has 2/3 different modes if I remember correctly.

- Is it possible to "force" or replicate the behaviour?
- Doest it actually steer when it feels light?

Tried in all (two) modes on mine - sport and normal, does it in both.

And yeah it does actually steer!

 

[nd-photo.nl]

Ok, that eliminates the steering rack itself (sorta)

I was thinking more towards the shocks. If the shocks dont work correctly, then the wheels are usually not constantly on the ground, which could account for light steering. See below

 

[piggasinnaris]

I also had this as a theory for a while, purely because about 3 months ago I replaced all shocks and springs with aftermarket (KYB) stuff, and all car parts are trash now.

But I discounted it purely because it happens when I'm going incredibly slow too, I'm talking driving out of my driveway onto level surface speeds, and a complete standstill where I doubt this really applies... but maybe not. Thanks for your reply @nd-photo.nl

 

[tracktoy]

have you had a look at this coding to see if it makes any difference.

Hardness of the steering wheel
* Applicable up to MY16 *
With this modification you can set the hardness of the steering wheel in different values.

1 - Module 03 - Brake electronics - Code (40168/20103)
2 - Adaptation
3 - Assisted counter-steering wheel - (Change value to the desired one - Strong default)
4 - Select one of the three options:

 

[piggasinnaris]

I haven't looked at any coding/software changes yet - nothing else has changed so I figure its a fault i'd rather I fix than just disable or change software

 

[nd-photo.nl]

When you also experience it with slowness, then I would also disregard the shock theory. KYB should be decent stuff.

Checked in with GPT

The 2016 SEAT Leon Mk3 (Typ 5F, 2012–2020) does not have variable steering ratio as standard across the range.

Here’s the breakdown:

• Normal models (Reference, Style, FR, etc.) → They use a conventional electric power steering (EPS) rack with a fixed steering ratio. Assistance level is speed-sensitive (lighter at low speeds, firmer at high speeds), but the actual steering ratio does not change.
• Performance models (Cupra versions) → Even on the Leon Cupra 280/290/300 of that era, SEAT did not fit a true progressive/variable steering rack as standard in 2016. However, VW Group did offer a Progressive Steering system (with a variable ratio rack) on the MQB platform cars (like the Golf GTI/GTD, Golf R, and some Audi A3/S3 models). For the Leon, this feature became available later on higher trims or as an optional package, depending on the market.

So, unless your 2016 Leon Mk3 specifically has the Progressive Steering option, it only has speed-sensitive assistance, not a variable steering ratio.