Technical Panda 4x4 system test

[JayAre]

I recently mentioned in another thread my concerns about 4x4 non-availability (can’t remember which) because there had been no way to test that the system on my 2016 TA (bought May last year) actually worked due to the complex electronics controlling engagement - unlike the purely mechanical systems of my 3 previous Panda 4x4s (the simplicity of which I prefer for the simple reason that, apart from mechanical failure - which would be noticed! - I could always rely on it being available when/if needed).

Tonight conditions were just right to go for a drive along the local single track ungritted roads which I know very well with nicely challenging gentle ups+downs and meltwater having refrozen on parts of the road surface (headlights would warn me of any other traffic - which there rarely is at nighttime).

Note:
Front tyres: AllSeason
Rear: Winter

ELD off
- stop with all 4 wheels on ice (a short stretch of road with ice free surfaces in between in all cases)
- accelerate hard
- car pulls away smoothly with no difficulty accompanied by almost constant flashing of the ESC warning light on the dash (the manual says: “the flashing of the ESC warning light on the instrument panel… inform(s) the driver that the vehicle is in critical stability and grip conditions” - critical yes, dangerous no due to the chosen conditions)

ELD on
- stop with all 4 wheels on ice (a short stretch of road with ice free surfaces in between in all cases)
- accelerate hard
- car pulls away very quickly almost as if on a normal road surface with NO flashing of the ESC warning light on the dash

I assume with ELD engaged the drive is transferred to the rear wheels more quickly obviating the need for ESC intervention hence no flashing light and no drama.

So I’m reassured by the outcome and (slightly) intrigued by the different results.

 

[The Panda Nut]

ESC / ASR switches off when you select ELD so no lights you should for that.. There will be very little difference in real terms but as you say you are in 4x4 mode so milliseconds will be shaved and maybe a little more as the power is already distributed more like 50 : 50 front and back. On snow and ice the system is so good its hard to tell if it is doing anything I find... If I have to drive up a kerb I use 4x4 as it saves a lot of strain its clear is doing its thing. I suppose a bit more initial traction makes all the difference.

 

[Herts Hillhopper]

I recently mentioned in another thread my concerns about 4x4 non-availability (can’t remember which) because there had been no way to test that the system on my 2016 TA (bought May last year) actually worked due to the complex electronics controlling engagement - unlike the purely mechanical systems of my 3 previous Panda 4x4s (the simplicity of which I prefer for the simple reason that, apart from mechanical failure - which would be noticed! - I could always rely on it being available when/if needed).

Tonight conditions were just right to go for a drive along the local single track ungritted roads which I know very well with nicely challenging gentle ups+downs and meltwater having refrozen on parts of the road surface (headlights would warn me of any other traffic - which there rarely is at nighttime).

Note:
Front tyres: AllSeason
Rear: Winter

ELD off
- stop with all 4 wheels on ice (a short stretch of road with ice free surfaces in between in all cases)
- accelerate hard
- car pulls away smoothly with no difficulty accompanied by almost constant flashing of the ESC warning light on the dash (the manual says: “the flashing of the ESC warning light on the instrument panel… inform(s) the driver that the vehicle is in critical stability and grip conditions” - critical yes, dangerous no due to the chosen conditions)

ELD on
- stop with all 4 wheels on ice (a short stretch of road with ice free surfaces in between in all cases)
- accelerate hard
- car pulls away very quickly almost as if on a normal road surface with NO flashing of the ESC warning light on the dash

I assume with ELD engaged the drive is transferred to the rear wheels more quickly obviating the need for ESC intervention hence no flashing light and no drama.

So I’m reassured by the outcome and (slightly) intrigued by the different results.

Good to hear …. It is creepily good at ‘just working’

Small comment… although the button is marked ELD, it doesn’t actually lock any diffs when it’s pressed. But it does physically engage the rear drive (ie forces 4x4), as well as disabling the traction control (hence no ESC lights) and also alters the throttle response. With the button ‘on’, the Electronic Locking Differential ‘effect’ is available, but only operates if one wheel spins much more than the other on the same end of the car. If ELD does operate and apply the brake on a spinning wheel, a green ELD light flashes briefly at the points it’s doing its stuff. (Never yet seen mine come on - in theory, that will only happen if one wheel is off the ground).

By the way, the older Panda 169s could use the electronic-free route of the viscous coupling because they didn’t have traction control. TC would have prevented the wheel spin that was needed to make the coupling connect. And of course the original 141 version had a very crude dog clutch to engage the rear - which could only really be done while stationary.

 

[JayAre]

Panda 169s could use the electronic-free route of the viscous coupling

ah, so the 312/9 4x4s don’t use a viscous coupling? (simple + cheap)
…in which case it must be a much more complex setup (expensive) quite apart from all the control electronics, maybe similar to the Haldex on my Octavia 4x4? (which had a separate ECU near the unit underneath at the back of the car I believe)

 

[Herts Hillhopper]

ah, so the 312/9 4x4s don’t use a viscous coupling? (simple + cheap)
…in which case it must be a much more complex setup (expensive) quite apart from all the control electronics, maybe similar to the Haldex on my Octavia 4x4? (which had a separate ECU near the unit underneath at the back of the car I believe)

Yes, there are similarities with the Haldex system: basically an electro-pneumatic engagement of a clutch, which operates more quickly than the viscous system could, and works in conjunction with the ABS, ESC and 'ASR' (anti slip regulation, or traction control). Involves more electronics, but works better too. I think all the electronics are within the main ECU.

 

[Eltezz]

@Herts Hillhopper just out of curiosity, is it actually pneumatic? Not hydraulic? Or is there an air pump somewhere in the diff?

 

[Herts Hillhopper]

@Herts Hillhopper just out of curiosity, is it actually pneumatic? Not hydraulic? Or is there an air pump somewhere in the diff?

No one really seems to know! There is a solenoid which operates a plunger, and the plunger has an o-ring seal on it. That might be just to keep oil in/water out, or might relate to it pressurising the unit in some way (like the plunger in a syringe). I did once find a definitive description from Fiat which I can't find now, and that described the electro-pneumatic actuator.

This older thread in this Forum goes some way to explaining it all...

Fiat Panda 4x4 system, "How does it work" ? | FIAT Panda (2012+)

I can't find any information on how the system is working. Is it 4x4 all the time, or only if you turn the nob on the centre console. ? Does it get automatically 4x4 with certain slip of the front wheels. ? Some info how it works would be great. ;)

www.fiatforum.com

As I said above, the press seem, to misquote all sorts of info (several tests still described the post 2012 car as just using a viscous coupling, which it clearly does not). Also, if you read all the reviews (actually, tue for any car) it's as if they all reuse the words from a previous test - even if wrong - rather than writing something new themselves. All the tests of the 4x4 Panda refer to is having excessive body roll owing to it being 5cm higher off the ground... but does it really? And many quote a raised air intake at 720mm -- which is also not true (it's just behind the headlight)

 

[SiloSean]

I didn't think you could mix tyres, if fitting winter tyres, then all 4 had to be winter tyres., same for all season. Is that not correct?

If you can mix winter and all season, then can you mix all season and summer tyres? I could do with some new tyres and would like to go back to all seasons. I just don't really want to change all 4 at once. If I could just put them on the rear axle and move the 2 best summer tyres to the front to wear out, it would be advantageous and less wasteful.

 

[JayAre]

I didn't think you could mix tyres, if fitting winter tyres, then all 4 had to be winter tyres., same for all season. Is that not correct?

If you can mix winter and all season, then can you mix all season and summer tyres? I could do with some new tyres and would like to go back to all seasons. I just don't really want to change all 4 at once. If I could just put them on the rear axle and move the 2 best summer tyres to the front to wear out, it would be advantageous and less wasteful.

agree it’s not ideal but some Googling showed it to be legal and the winters should be on the rear (as they are)

 

[Bonefish Blues]

agree it’s not ideal but some Googling showed it to be legal and the winters should be on the rear (as they are)

Except in good conditions where you should drive backwards to ensure the AS (which have the better grip in all but very extreme conditions) are at the rear

 

[Herts Hillhopper]

I didn't think you could mix tyres, if fitting winter tyres, then all 4 had to be winter tyres., same for all season. Is that not correct?

If you can mix winter and all season, then can you mix all season and summer tyres? I could do with some new tyres and would like to go back to all seasons. I just don't really want to change all 4 at once. If I could just put them on the rear axle and move the 2 best summer tyres to the front to wear out, it would be advantageous and less wasteful.

Most reputable tyre fitters would not allow you to fit all season at one end and summers at the other, nor allow all season at one end and winters at the other and the tyre makers are clear this shouldn't be done (for example, see https://www.goodyear.eu/en_gb/consumer/why-goodyear/winter-driving-all-season-uk.html#:~:text=Equally, you should not mix,losing control of your vehicle.) ... However, it is not illegal.

For the ESC system to work correctly (irrespective of whether the car is 4x4 or 2WD), all four tyres must be the same type and ideally the same make -- in fact the Panda handbook actually states this...

 

[Herts Hillhopper]

@Herts Hillhopper just out of curiosity, is it actually pneumatic? Not hydraulic? Or is there an air pump somewhere in the diff?

A later update... I finally found a reference the shows the 4WD system is made by Magna Steyr in Austria, and that the system is electro-hydraulic, not pneumatic. But still, no further detail on how it actually works (probably a patent thing?)

 

[Eltezz]

Got to be a hydraulically operated clutch via solenoid operated valve, I can't see what else would work and be simple ish.

 

[Bonefish Blues]

Most reputable tyre fitters would not allow you to fit all season at one end and summers at the other, not allow all season at one end and winters at the other and the tyre makers are clear this shouldn't be done. For the ESC system to work correctly (irrespective of whether the car is 4x4 or 2WD), all four tyres must be the same type and ideally the same make -- in fact the Panda handbook actually states this...
View attachment 458525

What does para 54 say about space savers? Seems to be about to contradict para 53?

 

[Herts Hillhopper]

What does para 54 say about space savers? Seems to be about to contradict para 53?

The system knows the size of the Fiat space saver... so the system knows it's being used and adjusts accordingly. Same with the 4x4 system, although (somewhere in the handbook) it says 'with reduced effectiveness' or words to that effect.

 

[Bonefish Blues]

The system knows the size of the Fiat space saver... so the system knows it's being used and adjusts accordingly. Same with the 4x4 system, although (somewhere in the handbook) it says 'with reduced effectiveness' or words to that effect.
View attachment 458533

Says hmmmm and scratches chin...

 

[JayAre]

tyre makers are clear this shouldn't be done (for example, see https://www.goodyear.eu/en_gb/consumer/why-goodyear/winter-driving-all-season-uk.html#:~:text=Equally, you should not mix,losing control of your vehicle.) ... However, it is not illegal.

Goodyear is very proscriptive - which is fine - while others simply ‘recommend’ (and also ‘recommend’ all tyres be the same type, tread, wear and manufacturer, and that full summer/winter sets are swapped over in, er.. ‘summer’ and ‘winter’)

Bear in mind no-one else drives (or will drive) my car, and I started driving on cross-plies in a 1960s Mini (sliding front windows, cable door-openers anyone?) and learned how to drive safely in all weathers +conditions and unmade roads to motorways and with no modern ‘driver aids’ - because they didn’t exist (actually not quite true - the Jensen FF* with 4x4 and ABS launched in 1966)

*Footnote - the FF pioneered the viscous coupling (‘Ferguson Formula’) developed by Harry Ferguson (the tractor man), GKN later buying a stake and then the rights to develop the FF VC for other car companies. Subsequently Steyr Daimler Puch (or its later iteration) worked with GKN to develop the FF VC for the Panda 169 4x4 - so the development ‘timeline’ is:
Harry Ferguson>FergusonFormula>Jensen FF(1966)>GKN(1968)>Fiat Panda 169(2003)
which means for the car geeks we can say that the Panda 169 is the grandchild of the fabulous Jensen FF

Slight Edit to clarify (I overlooked @Herts Hillhopper ’s previous link)
The (lengthy+technical!) thread on the Panda 4x4 systems previously linked by @Herts Hillhopper (above) mentions the GKN link:

Fiat Panda 4x4 system, "How does it work" ? | FIAT Panda (2012+)

I can't find any information on how the system is working. Is it 4x4 all the time, or only if you turn the nob on the centre console. ? Does it get automatically 4x4 with certain slip of the front wheels. ? Some info how it works would be great. ;)

www.fiatforum.com

 

[The Panda Nut]

No one really seems to know! There is a solenoid which operates a plunger, and the plunger has an o-ring seal on it. That might be just to keep oil in/water out, or might relate to it pressurising the unit in some way (like the plunger in a syringe). I did once find a definitive description from Fiat which I can't find now, and that described the electro-pneumatic actuator.

This older thread in this Forum goes some way to explaining it all...

Fiat Panda 4x4 system, "How does it work" ? | FIAT Panda (2012+)

I can't find any information on how the system is working. Is it 4x4 all the time, or only if you turn the nob on the centre console. ? Does it get automatically 4x4 with certain slip of the front wheels. ? Some info how it works would be great. ;)

www.fiatforum.com

As I said above, the press seem, to misquote all sorts of info (several tests still described the post 2012 car as just using a viscous coupling, which it clearly does not). Also, if you read all the reviews (actually, tue for any car) it's as if they all reuse the words from a previous test - even if wrong - rather than writing something new themselves. All the tests of the 4x4 Panda refer to is having excessive body roll owing to it being 5cm higher off the ground... but does it really? And many quote a raised air intake at 720mm -- which is also not true (it's just behind the headlight)

No it doesnt. Its not excessive and driving it back to back with the regular Panda , while it feels a little different, its the improved ride comfort that you notice most not body roll. Only driving like a hooligan would induce anything of note. Only a motoring journlist woulf drive like that! I agree with your sentiments about regurgitation of words. Most of what you read about the Panda 4x4 and the Cross versions is rot. The much improved ride heigh of the cross... Kts much better off road ability.... I have words for these stupid comments but wont use them. It makes you wonder if anything written by the motoring press has any validity whatsoever.

I prefer Clarksons style of this is best becasue I say so. You can at least compare what he says about one car compared to another. The reviews have one thing in common. Him. I dont always agree with him but within his own parameters hes at least straight. Ignore all comments on caravans and diesels though. Journalistic license...... LOL

 

[Herts Hillhopper]

No it doesnt. Its not excessive and driving it back to back with the regular Panda , while it feels a little different, its the improved ride comfort that you notice most not body roll. Only driving like a hooligan would induce anything of note. Only a motoring journlist woulf drive like that! I agree with your sentiments about regurgitation of words. Most of what you read about the Panda 4x4 and the Cross versions is rot. The much improved ride heigh of the cross... Kts much better off road ability.... I have words for these stupid comments but wont use them. It makes you wonder if anything written by the motoring press has any validity whatsoever.

I prefer Clarksons style of this is best becasue I say so. You can at least compare what he says about one car compared to another. The reviews have one thing in common. Him. I dont always agree with him but within his own parameters hes at least straight. Ignore all comments on caravans and diesels though. Journalistic license...... LOL

To be fair, the press basically re-use words from the press releases they are supplied with… a Fiat release described the 4x4 Cross as having enhanced off road capability (compared to the regular 4x4) and an increase in ride height- both are true, but only owing to HDC and marginally taller tyres…

 

[Herts Hillhopper]

Goodyear is very proscriptive - which is fine - while others simply ‘recommend’ (and also ‘recommend’ all tyres be the same type, tread, wear and manufacturer, and that full summer/winter sets are swapped over in, er.. ‘summer’ and ‘winter’)

Bear in mind no-one else drives (or will drive) my car, and I started driving on cross-plies in a 1960s Mini (sliding front windows, cable door-openers anyone?) and learned how to drive safely in all weathers +conditions and unmade roads to motorways and with no modern ‘driver aids’ - because they didn’t exist (actually not quite true - the Jensen FF* with 4x4 and ABS launched in 1966)

*Footnote - the FF pioneered the viscous coupling (‘Ferguson Formula’) developed by Harry Ferguson (the tractor man), GKN later buying a stake and then the rights to develop the FF VC for other car companies. Subsequently Steyr Daimler Puch (or its later iteration) worked with GKN to develop the FF VC for the Panda 169 4x4 - so the development ‘timeline’ is:
Harry Ferguson>FergusonFormula>Jensen FF(1966)>GKN(1968)>Fiat Panda 169(2003)
which means for the car geeks we can say that the Panda 169 is the grandchild of the fabulous Jensen FF

Also, here’s a previous (lengthy+technical!) thread on the Panda 4x4 systems:

Fiat Panda 4x4 system, "How does it work" ? | FIAT Panda (2012+)

I can't find any information on how the system is working. Is it 4x4 all the time, or only if you turn the nob on the centre console. ? Does it get automatically 4x4 with certain slip of the front wheels. ? Some info how it works would be great. ;)

www.fiatforum.com

Yup - you’ll spot I was part of that earlier long thread too