Technical panda 4x4 not working

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Technical panda 4x4 not working

Jenn

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Hi, i have just bought my first Panda 4x4 and i really like it. Never owned 4x4 before so its all new to me. Parked it on the grass outside my house over night when it threw it down with rain. Next morning found the front wheels had sunken down in the wet ground, no problem i thought. Started car up to move and front wheels started spinning, i was stuck! I thought the back wheels would grab the drier ground and get me moving, but the back wheels didnt go round at all, put the ELD on hoping that would get me out, but no, the back wheels remained stationary. So i have rung garage were i bought the car from and told them i think the 4 wheel drive isnt working, they going to check it for me. Any advice would be appreciated.
 
Is the prop shaft there?
The centre bearing of the prop wears. From Fiat, you have to have a full prop, over £1000, but aftermarket centre bearings are available, so a repair is not difficult. There have been many owners found that the prop has been removed, to prevent the vibration from a dead centre bearing.

On the front of the diff is a viscous coupling. These can wear out. There's a recent thread about this, and a good result from a company that refurbished one. So no worries there either.

The seller might appreciate this info.
 
To Simon, if it has an ELD button, its a 4x4...

To Portland Bill - similar: if it has 'ELD' it is either the previous (pre 2012) 'Cross' model or a post 2o12 4x4 -- neither of which are likely to be sufficiently old to have had the prop shaft removed, especially if sold by a dealer as a 4x4. Post 2012 4x4 does not use a viscous coupling: its an electronically-operated system now (and was on the old 'Cross' too. Only the pre 2012 4x4 used a viscous coupling)

And to Jenn -- part of the issue may be down to the way the 4x4 system works. Basically if one front wheel spins, it will engage 4x4 to add rear drive. But if both are turning at the same speed, the system doesn't really think its stuck. If you can (or could have) encouraged one wheel to spin slower than the other (eg by jamming something like a brick under it) the system should then detect the imbalance and make the rear drive engage. However, pressing the ELD button should force 4 wheel drive at slow speeds: did the yellow 'ELD and diff lock' symbol come on in the speedo, and the green LED on on the button? The green light shows 4x4 is forced, and the yellow flashes when the ELD system is operating (when it 'brakes' a wheel to stop it spinning) If the 4x4 system detects a fault when that button is pressed it will show a warning triangle in the dash and display '4x4 not available'. If the ELD system is faulty, then, when the button is pressed, the lettering 'ESC' will flash in the rev counter and a message will show 'ELD unavailable'
 
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Thank you everyone for your replies, i have taken the car back to the garage i bought it from today for them to have a look at. To cut a long story short they couldn't find out what was wrong with it so they have booked it into a Fiat specialist garage for me next week. The car has a three month warranty, so i won't have to pay for getting it sorted out. Its rather disappointing just having bought this car, but its better finding out about this now rather than later when the warranty has run out. Apart from this hiccup i love this little car, its only 2014 and the first time i have been able to afford one at this age.
 
There have been a few reports of the electro pneumatic valve failing.
It's by no means common, but it can happen.

This valve controls the coupling, thus the power delivery to the rear axle.
Though I would have suspected a dashboard full of warning lights and messages.

Hopefully it should get sorted fairly quick and painlessly.
Hang in there, as when it all works, it's brilliant!
 
There have been a few reports of the electro pneumatic valve failing.
It's by no means common, but it can happen.

This valve controls the coupling, thus the power delivery to the rear axle.
Though I would have suspected a dashboard full of warning lights and messages.

Hopefully it should get sorted fairly quick and painlessly.
Hang in there, as when it all works, it's brilliant!

Don't you get a message like ELD not available or something like that - in fact shouldn't there be a diagnostic message on start up?
 
Don't you get a message like ELD not available or something like that - in fact shouldn't there be a diagnostic message on start up?
See my earlier reply...
"If the 4x4 system detects a fault when that button is pressed it will show a warning triangle in the dash and display '4x4 not available'. If the ELD system is faulty, then, when the button is pressed, the lettering 'ESC' will flash in the rev counter and a message will show 'ELD unavailable'"
 
Yes I would presume so, but the OP obviously isn't that familiar with the car yet, it could be complaining and they just haven't realised it.

There are plenty out there tootling about with warning lights on.
How often do you see cars with rear fogs on in broad daylight!
 
How often do you see cars with rear fogs on in broad daylight?

Less often than cars with no lights on at all in thick fog or well beyond twilight and even less often that diesel cars parked up with the engine running for minutes on end...
 
Is the prop shaft there?
The centre bearing of the prop wears. From Fiat, you have to have a full prop, over £1000, but aftermarket centre bearings are available, so a repair is not difficult. There have been many owners found that the prop has been removed, to prevent the vibration from a dead centre bearing.

On the front of the diff is a viscous coupling. These can wear out. There's a recent thread about this, and a good result from a company that refurbished one. So no worries there either.

The seller might appreciate this info.
Portland-Bill you have maybe helped me in identifying the vibration felt throughout my 4x4 MJ, that being the central prop shaft bearing.
It was present sometimes from when I bought the car but as the Bridport Fiat supplying Dealer was insistent that we returned the car to them under warranty, not what the salesman told us, he said that we could use a local Fiat Dealer and it being a 150 miles round trip I’ve put up with this.
I’ll get my local very helpful Ford Dealer to check it out.
 
Finally got things sorted out, i am not very mechanically minded but i did ask what the trouble had been with the 4x4 system not working.
I have been told it was an electrical fault with the ICU or is it ECU? going to the gear box, apparently it didn't take a lot of fixing.
The garage i bought the car from sent it to a Fiat garage Stoneacre at Chesterfield and got it sorted for me. Just want some more snow now to test it out! :)
 
its def not working. normally it would do its thing seamlessly. I wiill leave it to the experts to explain how it works. there are some reallybgood posts on this on here somewhere. Eld is really only a benefit in the most extreme conditions off road. good luck with getting satisfaction. I can confirm that when working these things will go nearly anywhere.
 
I suspect there was a wiring connection issue to the electro pneumatic valve.

There have been reports of problems, I think water gets into the connector.

Some have been fine after a clean and a fiddle, others have needed replacement as they failed again soon after.


I wrote this a while ago and it hopefully explains the differences between the old, viscous system and the newer, electro pneumatic valve system.

Both systems front to rear torque systems perform similarly, though one is mechanical and the other electrically controlled.

The old viscous coupling on the 169 "Climbing" model is basically two shafts joined together by plates in a tube filled with thick fluid.

Every second plate is locked into one shaft, the others in between are locked into the other shaft. (very similar to a motorbikes wet clutch).

With no pressure on the plates, they slip past one another and no torque transmits from one shaft to the other.

When it all starts slipping the thick fluid heats and expands to drag on the plates, thus sending torque through it.
The more slip, the more drag on the plates, the more torque.
It's totally automatic and self regulating.


The later models with the electric system uses a power transfer unit on the back of the gearbox, similar to the viscous system but with an electro pneumatic actuator on the rear diff instead of a viscous coupling to engage and transmit power to the rear axle.

This valve uses small electric currents to vary the valves position thus controlling variable power to the rear axle as needed.

The valve is not just a on or off switch, but will vary depending on the differing levels of torque between the prop shaft and the diff.
It will transmit up to 50% of torque to the rear when needed.

Now where the two systems differ is with this electro pneumatic valve system, it's easier to over ride and pre lock the torque 50/50 than it is to pre lock a viscous coupling, it's just a matter of signalling this valve.

To pre lock a viscous coupling, there needs to be some way of altering the state of the fluid in the system (with a pump) or some other way of locking the two shafts together.

I believe due to weight/cost/reliability Fiat did not include a front to back lock on the old viscous system.

This pre locking is part, but not all of what the ELD system

So both can alter power between front and rear axles, though only the later electronic system can pre lock the front to back transfer of torque.

Due to the other systems fitted to the later models, like the stability control (ESC) and ABS, they can also "lock" the diffs side to side, though it's not a true lock, just the effects are similar.

Under normal conditions, if one wheel on a powered axle spins due to lack of grip, the open diff will transmit all the power on that axle through the path of least resistance, ie to the spinning wheel. The other wheel on that axle, even through it might have traction, doesn't receive any power and sits there idle.

By using the ESC it can detect a slipping wheel and using the ESC & ABS systems it can grab the brake for that wheel, thus sending the torque to the other wheel which otherwise would be left unpowered, so now this other wheel has a chance at gripping and moving you.

The ELD is speed limited, as what works for low traction situations doesn't for higher speed cornering.

So by pressing the ELD button you pre lock the power to the back axle with 50% of power and alter the ESC system, already to grab the brakes on slipping wheels making it more more capable, grip wise, than it otherwise would be.

The ELD a bit of a step up from the viscous coupling, as unlike the pre lock, electro pneumatic valve system, the viscous's front to back torque is a reaction to low grip, so you are already loosing it before it actually operates fully.

Though the side to side "lock" using the brakes is a reaction system rather than a pre locking system, the old system had nothing similar.
 
First of all, glad it got sorted out. Electrical issues are probably among the most annoying, like an ingrown nail: tiny faults that mess with everything.

Small note: the old (previous generation) Cross also had an ELD (not available in the Climbing or Trekking models of the 169 series), but unlike the solenoid in the current system it used a hydraulic valve to boost hydraulic pressure and lock the differential. It also incorporated the ABS and ESP systems for a faux axle lock similar to the current system, although it was decidedly more rudimentary than the algorithms in the current 4x4.

Side note: due to the increasing complexity of the current generation 4x4 system, most of the companies in Italy that specialized in providing aftermarket improvements to the Panda 4x4 system aren't even attempting to develop equipment for the new models. Everything from low ratio axles, mechanical locking diffs and adjustable limited slip differentials are available for previous generations but not the 312. One of my favorite mods are the variable center diffs some companies make for the 169 where they replace the input shaft of center diff with a splined rod, and the plates with a wet clutch pack. The hydraulic valve is taken out and a line boosted from the master cylinder is drawn, with a big old lever mounted into the car next to the gear lever. The fun bit is the more you pull the lever, the more power is (manually) sent to the rear axles until the clutches fully engage, locking everything at 50/50, but you can have pretty much any ratio in between that you'd like. I can't remember who made this, might have been Prometeo Meccanica or AGS.
 
Those people are mad. Their workshop is chock full of interesting projects and engineering samples. They've basically become a specialty engineering consultancy that specialize in rapid prototyping and overengineering (like the old days). It's not just diffs and axles and running gear, they had some tube frame chassis laying around when I visited which means they might also be manufacturing small volume track toys.
 
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