I managed to get my Yeti into a precarious position on Saturday.  Trying to turn around on a narrow-ish rural road, I reversed in to what looked like a sizable area of level-ish verge in front of a field gate.  Unfortunately I misjudged the amount of steering input required and turned in too tight, finding two parallel ditches hidden in the long grass.  All totally my fault.

 

So there we were with some wheels apparently having traction - because the car would move slightly when I applied drive - but the nearside front clearly spinning uselessly.  On further inspection it was clear that the car was actually slightly grounded on the floor pan, between the front and rear nearside wheels.  Engaging my brain for probably the first time since the incident began, I told myself that the electronics should be able to deal with this by braking the spinning front wheel.  That's what EDL does, right?  I made sure to follow Llanigraham's frequent advice, to let the electronics do their work and not simply to lift off a the throttle at the first sign of slippage.  Unfortunately this achieved nothing: the front wheel sat there merrily spinning away and the car went nowhere.

 

Upon yet further inspection around both sides of the vehicle, it became apparent that the offside rear was also hanging in mid-air, due to a combination of the grounding and the nearside front being in a ditch.  Thus that wheel too was spinning uselessly - something I hadn't noticed before because of course it wasn't making any noise.

 

Luckily, at this point a helpful fellow in a Hyundai pulled up and asked us of we needed any help.  He hooked the Yeti up to his tow hitch and gave me a gentle backwards pull until I was back on an even keel, with nothing worse to show for the adventure than a big tuft of coarse grass jammed against the sort of wedge-shaped thing which protrudes from the floor pan a foot or two in front of the rear wheel.  (Anyone know what that is for?  Apart from collecting grass if you happen to be foolish enough to ground the vehicle on a deeply rutted verge - it seems to be very good at doing that.)

 

Now, at the time I assumed that the Yeti's electronic wizardry had been defeated by having no traction on two wheels simultaneously, especially since they were diagonally opposite.  Then I started consulting the official Skoda documentation and things became less clear.  The owner's manual for my 2010 Yeti, in the section for EDL, states:

 

EDL prevents the turning of the respective wheel of the driven axle. EDL brakes the spinning wheel, if necessary, and transmits the driving force to the other driving wheel. Driving becomes easier on road surfaces with different traction under each wheel of the driven axle.

 

Which isn't particularly clear.  Nor does it help when, in the section about the Off-Road Button (which I did try using) it apparently uses the term "EDS" instead of "EDL", and states:

 

A spinning wheel or wheels are braked earlier and with more force than with the intervention of the standard EDS system.

 

The latest edition of the Yeti handbook seems a little less confusing.  Under EDL it states:

 

Should only one drive wheel begin spinning on a slippery surface there will be an appreciable difference in the speed of the driven wheels. The EDL function brakes the slipping wheel and the differential transmits a greater driving force to the other driven wheel.  This control process is also accompanied by noises.

 

which seems to suggest that EDL can't cope with two wheels slipping.  However, it then goes on to say:

 

EDL is activated earlier in the Off-road mode than in the normal mode. The brake pressure builts up more quickly on the slipping wheel, on one axle, as well as diagonally.  (Emphasis is mine.)

 

Unfortunately, that still leaves me confused.  Should my 4x4 Yeti have been able to get traction with only two wheels on solid ground, thanks to EDL, with or without the off-road button?  Is there a difference in the EDL implementation between 2010 and 2015 models?  I don't recall hearing any noises which might have been EDL operating (I presume these would be similar to the noises created by ABS).

 

I have subsequently looked to see if there were any error codes in the ECU (using TorquePro on my phone hooked my cheapy bluetooth ODB II dongle).  Nothing was showing, but then I'm not sure that proves very much.

 

Does anyone have any useful information or insights that could reassure me that the car was doing the best that it could, and it was my own idiocy which ended up with me getting stuck?

 

(Unfortunately this incident was not the last of the excitement I had with my Yeti this weekend.  More of that later, perhaps, once the bodyshop has provided the insurers with an estimate...)

Edited 15 June, 201510 yr by ejstubbs

mmmm......sounds expensive

Last week I happened to be browsing Youtube for videos of Yetis offroad.

Unfortunately I don't remember which one now, but there was one video of a Yeti with diagonally opposite wheels off the ground, and it was still able to progress. All of the vehicle weight was on the other two wheels though, so they had plenty of traction.

Maybe, because it was partly beached, there simply wasn't enough weight & traction available on any wheels to move the car ?

 

(And yes, I've wondered what purpose that wedge-shaped bit serves too!)

Were the tyres fitted any use if there was mud to be encountered, or conditions liable to have the tyres filled with gloop.?

No traction equals no action often no mater the electronics reactions.

Lack of articulation being a bit of an issue as well.

If you had tried easing up your handbrake, to slow the rear wheel,  while under power that may have been worth a try. Had a similar nightmare with a non haldex quattro but eventually got away.  

Maybe, because it was partly beached, there simply wasn't enough weight & traction available on any wheels to move the car ? 

 

Yes, I'm beginning to suspect that might have been the case.

 

If you had tried easing up your handbrake, to slow the rear wheel,  while under power that may have been worth a try.

 

Interesting suggestion, I didn't think of that.  One thing I was starting to consider was somehow to get as much weight as possible over the offside rear wheel, in the hope that it could be brought in to sufficient contact with solid ground to leave just the front nearside without traction.  However, with the grounding point being near the middle of the vehicle, and most of the weight being the engine at the front, I'm doubtful that would have been feasible without a source of depleted uranium* readily to hand...

 

Fortunately Mr Hyundai turned up with a towing strop before we had to get involved in any more complicated shenanigans (or give up and call out the AA).

 

* Or a cage of two of gold bullion.  "Hang on a minute lads, I've got a great idea.  Er..."

I don't recall hearing any noises which might have been EDL operating (I presume these would be similar to the noises created by ABS).

That's weird. The noises that EDL makes are usually louder than those from ABS. Mostly they consist of crackle, accompanied by occasional thuds. I've been in situations when two wheels of my Yeti were off the ground diagonally many times and EDL worked like a charm each time.

Is there any reliable way to test whether the Haldex, EDL etc are working correctly? In the absence of any snow or ice at this time of year (yes, even in Scotland) it doesn't seem to be particularly straightforward to trigger loss of traction at one or more wheels in a controlled manner. As I said previously, TorquePro reports no errors from the ECU - but then I seem to remember reading here recently about a Haldex fault that didn't show up in the diagnostics, and which required physical inspection to confirm.

try it on sand or small gravel, try to spin the wheels with rapid acceleration from standing!

probably an observer with you

Is there any reliable way to test whether the Haldex, EDL etc are working correctly?

This is the easiest way to test EDL:

It seems to me from looking at that video that none of the tested cars can be called 4x4 in the "true" sense of the phrase. ie if one wheel has traction the vehicle will be able to move. As one was a VW I guess the Yeti is the same.

This is the easiest way to test EDL:

 

Hmm.  There are quite extensive sand dunes around the East Lothian coastline but people tend to be fairly protective of them* and I doubt they'd take kindly to me abusing one for such a purpose.

 

* Unlike further north where they allow deranged, toupeed Yanks to turn them in to yet another golf course...

 ^  oooooooooooooooh do I detect malice or irony!!  ; - D)

Is there a place in Europe where they don't blame the Yanks? 

OT.

 But The Donald also has Sandy Bunkers and a Lighthouse in Sunny South Ayrshire now.

5 Star Golf Resort & Spa and holding the Womans British Open in July.

 

Best we do not mentions Hispanics and Building Walls, 

he might be a bit touchy today on that subject.  

Just imagine him with the Big Red Phone and the Button or the control to command the use of the Launch Codes.

First target would be 'The Windmills'.

 

(PS,

is he a Yank,? his Mother was a McLeod from Scotland!)

 

Edited 17 June, 201510 yr by goneoffSKi

is he a Yank,? his Mother was a McLeod from Scotland!

 

He is a citizen of the United States under US nationality law.  Given that he has announced his intention to run for president next year, if any citizenship shenanigans eg to avoid federal taxes were to come to light, that might be a tad embarassing.  But then again, other people's opinions don't seem to register much in his world...

 

We now return viewers to the advertised programme.

Maybe, because it was partly beached, there simply wasn't enough weight & traction available on any wheels to move the car ?

 

(And yes, I've wondered what purpose that wedge-shaped bit serves too!)

 

I suspect that this is the answer. 

I've certainly had 2 diagonal wheels in the air (cross-axled) and had drive.

 

The funny wedges are (I think) an aerodynamic device to alter the air flow under the car.

Were the tyres fitted any use if there was mud to be encountered, or conditions liable to have the tyres filled with gloop.?

 

Tyres were the OE Dunlops which IMO are fairly rubbish on tarmac let alone grass or mud.  However, the tread (such as it is on those tyres) wasn't filling with crud on any of the wheels.

 

I think I'll hold off 'testing' the Haldex/EDL until I've put new tyres on - the Dunlops are probably due for replacement in terms of age (though there are no cracks, splits or other structural problems visible) but they do still have an annoying amount of tread left on them...

It seems to me from looking at that video that none of the tested cars can be called 4x4 in the "true" sense of the phrase. ie if one wheel has traction the vehicle will be able to move. As one was a VW I guess the Yeti is the same.

My Land Rover Discovery needed more than one wheel to have traction to work.  Only the centre diff was lockable.

Its all in the tyres. The fact that friction through been beached would of been high wouldnt help either.

 

I used to have a Freelander Mk1 and when I had it with road tyres on it wasnt the best on the slippy stuff at all, the treads on normal tyres are designed to push out the water as that part touches the tarmac. Proper off road tyres (depending on their off road bias of course) are designed to grip the mud like a hiking shoe would and then once spinning to through that mud out the tread so when it hits the mud again it is clean and ready to bite again.