4x4 downhill hesitation

[Lyonzo]

In the last couple of weeks on 2 seperate occasions while travelling down a steepish hill on the road, the car has held back or hesitated and the traction control light flashed on and off a few times.

When I came to the bottom of the hill it returned to normal and the light went out.

Any idea what thats about? I assume it isn't a trait of the 4x4 system?

[mbames]

I think a faulty MAF can cause the traction control light to flash on a 1.8t based car.....

Can you get the car scanned for fault codes?

[Lyonzo]

I had it scanned last week and nothing came up.

Surely the maf wouldn't affect down hill driving only would it?

[mbames]

My only thinking was that going down hill the engine would be under less load and using less air but maybe the MAF was playing up a lower airflows.... or something?! Ultimately though, that is a guess

Edited 29 December, 2012 by mbames

[snow_muncher]

Its basically the car doing its thing

Could have been either the EDL engaging (electronic diff locker - basically a more aggressive form of ABS) and/or the ASR system (anti slip regulation - basically blips the engine power)

The light is shown because excessive slip outside normal parameters has been detected

[Volvomeg]

Were you on over run or did you have accerator pedal pressed when this was going on

[Lyonzo]

Its basically the car doing its thing

Could have been either the EDL engaging (electronic diff locker - basically a more aggressive form of ABS) and/or the ASR system (anti slip regulation - basically blips the engine power)

The light is shown because excessive slip outside normal parameters has been detected

Brilliant, thanks for that. Makes a change from there being something wrong!

Funnily enough it's happened in the exact same place all 3 times, so it must be steep enough to trigger it.

Edited 30 December, 2012 by Lyonzo

[pinkpanther]

Strangely enough mine does this also (2002 1.8T 4x4 estate). It only ever happens when turning sharp left and going downhill. The traction control light briefly flickers and I can feel the ESP system "kicking in".

I initially assumed there must be some diesel / oil on the road, causing a momentary loss of grip / traction, but have driven along the same road in a variety of different cars and haven't noticed the same effect.

I've scanned the car with Torque (http://torque-bhp.com/) and have nothing stored in the ECU. The car was also given a clean bill of health by both the local main dealer and Shark.

I understand the ESP system relies on a variety of sensors and assumed it must relate to maybe a ?? yaw sensor, as the car is always going downhill and turning (at low speed) when the light flashes and certainly not traveling fast enough to purposely cause any loss of grip / traction.

[will_]

Strangely enough mine does this also (2002 1.8T 4x4 estate). It only ever happens when turning sharp left and going downhill. The traction control light briefly flickers and I can feel the ESP system "kicking in".

Mine's exactly the same. Applying power while turning (definitely left; possibly right) while going down hill (especially entering a steeper section) will fool the ESP into thinking something awry. The ESP light flashes and the power comes off. It won't let me re-apply the power until I remove my foot from the accelerator.

Edited 9 June, 2013 by will_

[MarkyD]

Well well well, I have noticed this happening on a particular tight downhill left turn with a bump and nowhere else. Doesn't happen every time, in fact it hasn't happened for a few weeks now and I go the same route nearly every day. I was beginning to suspect a Haldex problem and had in mind to log some runs with VCDS and see if I can see anything odd. Find it strange this piece of road would fool the electronics so much.

Mark