[Audi A3/S3] S3 4wd system

[Jamescalv]

How can you tell if the 4wd system on the S3 is working? It’s only snowed once since I bought the car and I could tell the 4wd was working then. However today I had to pull away quickly from a wet roundabout which is always really slippy and on a slight hill. So I gave it a few revs and pulled away fast thinking the 4wd will take care of everything, yet the car spun the wheels for a second until I let off. I doubt that all 4 wheels would have been spinning would they? I’m guessing that it was just the front wheels.

So today’s question is: how do I know if its still working all the time?

I'm sure it works most the time as it NORMALLY has much better traction off the line in wet conditions compared to other FWD cars i've had.

[Paul]

On the S3 its easier to tell when its NOT working.

certainly on mine it is.

If i disable it. (will come to this in a minute), my remapped car becomes an animal, and cannot get the remapped power down through the front wheels even in the dry.

if your haldex was not working, I would expect it to be wheel spinning all the time, especially on launch..

a quick test, and do this on a clear straight road, is before pulling away, pull the handbrake on one notch, just so the handbrake light comes on.

Then go for a drive. When conveinient, give it some harsh acceleration, but make sure your fully in control.

A remapped car will snake and torque steer, and struggle for grip.

Return haldex to normal, and you smply dont get this.

Haldex will allow front wheels to slip momentarily in normal action. Its how the sytem works, and triggers the haldex to operate.

[Jamescalv]

So does the haldex system become disabled when the handbrake light is on?

[Paul]

yes.

haldex is disengaged on (any) braking as you dont need 4x4 to brake.

Hence handbrake on one notch fools car into thinking its not needed.

Only use as a brief test though.

[Jamescalv]

OK cheers, i'll give it a go.

[whisky]

Is this the same on the new A3s like mine Paul? I might give it a go...

[Paul]

havent tried, but i should think it works on same principle, even if its the newer generation haldex.

I would only suggest you use it for brief diagnostic purposes, and NEVER use it for 2wd rolling roads.

The key to doing no harm is that the rears are allowed to freely rotate at the same road speed the driven fronts are.

then its no different to how the haldex operates, switching in and out as required.

[Jamescalv]

I gave this a go the other day, the 4wd system deffo works . As you say it becomes a bit of an animal not being able to get the power down, mine is a standard S3 too.