Technical Panda Cross Update

[doctorchris]

Well, I've not posted much of late and the main reason is that I've had a bump in my Cross and it's in the repair shop just now.
Before it went in for repair, I drove in the snow and the electronic 4x4 sysem promptly threw up a fault warning. Now, the mechanical side of things was obviously working since I could give it full throttle on snow without a hint of wheelspin but the electronics were not happy.
Bloody electronics, I say. I'll just have to book it in for a check at the Fiat dealer.

 

[DraigFlag87]

Sorry to hear you had a bump, was it serious? When i drove the Cross, after a bit of off roading, i was just about to go through a huge puddle when i heard a beep and it read "4x4 mode not available" on the screen. I was confused, so i never risked the puddle! It never did it again though, was it a similar glitch with you?

 

[mollyandbuttons]

Had our Panda Cross for a month now. Yesterday. skipping over the snow and slush on the winter tyres it came with was fantastic. Could drive up hills no problem.

Until on one corner a beep, the dashboard 4x4 indicator permanently on and the message "4x4 mode not available". When the engine was turned off and restarted the indicator was normal (out).

I don't particularly want the dealer to look at it, as there will be nothing to see when the car is taken in. But I would like to know if it's a problem or a feature.

Otherwise, delighted with the Cross, but is it as good as the original Panda 4x4 I drove nearly 20years ago ? I had two, the first with those deck-chair seats and the second with the Fire engine.

I am sure the consumption, about 44 mpg, will improve if I change the tyres next Spring.

Mike O

 

[ScoobyChris]

I don't particularly want the dealer to look at it, as there will be nothing to see when the car is taken in. But I would like to know if it's a problem or a feature.

It may well be that a fault has been logged in the ECU history though so when they plug their scanner in they will hopefully see a reason why the 4x4 disabled itself. I'm guessing it's a problem

Chris

 

[james_f]

Must say that 'my' Panda 4x4 (petrol) has been utterly fantastic over the past two days up here in the Yorkshire Dales. About 4" of snow yesterday and much icy-ness, esp this morning, and together with the new tyres (Vredestein Quatrac2) just great fun bombing about all over the place! Hard to make them unstick. Times when low power / torque is a really good thing!

No warning signals either, so maybe problems confined to the Cross? Then again, the diesel 4x4 has been on sale in Europe for years hasn't it?

 

[stephenbeetleman]

Sorry to hear you had a bump chris, hopefully it'll not cost much to put right. I had sort of wondered why you hadn't been on singing the praises of the cross and its abilities as it is a great wee car. Good to hear also that the rest of you all have your pandas out for a play in the snow/ice! Happy 4x4ing!

 

[doctorchris]

The fault indication described by the others posting here is exactly the same as on my Cross. It occured once when cornering on slushy snow and a second time when I drove through standing water at the side of the road. I wonder if there is a loose connection or one that is not very well waterproofed?
The petrol-engined 4x4 will not produce this type of problem as its 4x4 system is purely mechanical. My 4x4 Climbing did 33,000 miles without any 4x4 system fault, or any other significant fault in fact.
The insurance co will pay for the bump but the car has been in for repair for over a week now. I'm not surprised as a new rear bumper is needed and I think it will be hard to get hold of. Even bumpers for the 100HP are hard to get and the Cross is rarer still.
I have a Corsa loan car which does not grip well on snow. However, having a car nearly identical to my daughter's has allowed me to tell her that they all seem to have clutch judder when the clutch is cold so there's no point in her pestering the dealer to repair it.

 

[Herts Hillhopper]

Oh - sorry to hear about that. Thought you'd been quiet. Did someone go into you, or something more untoward?

The fact that there's a message saying 4x4 not available does seem to point to an electronically-managed coupling doesn't it. The all-mechanical 'Climbing' sound almost 'better' then? I mean, if it doesn't like getting wet, that's not ideal is it?

I'm still waiting for the snow here. Been bl**dy cold and lots of ice last few days but so far no snow. Shame as I'm back on 4 Quatracs after two days on the horrible spacesaver tyre after nicking the sidewall of the nearly new tyre on one of Hertfordshire's famous crater-like pot holes (I think -- can't see how else I did it). I can tell you the handling is 'interesting' on that, and zero grip too.

Pete

 

[Toomanytoys]

I thought the cross was the same but with the electronic rear difflock as standard......... does it have a "decoupler" too??
Not the same "clutch" type as the SX4/Sedici??? they seem to "overheat" the coupling, but only with some abuse.....

 

[doctorchris]

I really don't know how the 4x4 system on the Cross operates.
There's no longer a viscous coupling between the propshaft and the rear diff but there are 2 large cylinders emerging laterally from the rear diff. The diff lock is a virtual system, in that the ABS system detects a spinning wheel or wheels and brakes them to restore power to the wheel(s) that have grip.

 

[ScoobyChris]

Is it permanent 4wd or is it similar to the Haldex system used by VAG where they have a dedicated ECU to engage the rear wheels when needed and then distribute power to the ones with most grip?

If it is like the Haldex one, then a poorly located ECU could certainly be prone to nasties! How long does it take for the warning message to disappear?

Chris

 

[doctorchris]

4WD system on the Cross only sends drive to the rear wheels if the fronts lose traction but the system is "permanent" in that no driver input is required to engage the system. I suspect that some form of viscous coupling is still involved at the rear but maybe it's now integrated into the rear diff housing.
The 4x4 fault message remains on until the vehicle is stopped and the ignition switched off.
However, despite the fault message, I'm pretty certain that 4WD continues to be provided as the car will pull away on ice or snow without any wheelspin which would not be the case if front wheel drive only was available.

 

[mollyandbuttons]

It may well be that a fault has been logged in the ECU history though so when they plug their scanner in they will hopefully see a reason why the 4x4 disabled itself. I'm guessing it's a problem

Tthis afternoon, my clever little Panda's ECU ordered an electropneumatic valve ..... possibly from some inter-galatic warehouse given the delivery time. I had no idea Doctor Who designed the Panda.

Do such things exist on earth ? Must update my Haynes manual collection immediately for the Cross !

Mike O.

 

[Toomanytoys]

Mmm I cant see Fiat totally redesigning the system for 1 model.. So I suspect its the same as the normal system, a VC works all the time (well of course it will fail eventually, abuse/age/miles) so I suspect it could be something to do with the "diff lock".. sounds like a poorly placed connection..

 

[doctorchris]

Mollyandbuttons, tell me more about the electropneumatic valve, since I'm sure that when I take my Cross to the dealer they will not have a clue as to the nature of the fault and if I have some useful information it will speed up the diagnostic process.

 

[mollyandbuttons]

Mollyandbuttons, tell me more ......

Not much to tell. The service receptionist said the ECU diagnostics showed a fault and a part had been ordered, but did not know when it will be delivered.

The mechanic who did the work was out on a test drive, so I could not discuss with him. I have no idea where this part is fitted on the car .... and its too cold and wet to crawl under the car to find out.

How do you know when the Cross is in 4 x 4 mode ? It may be difficult to confirm whether the fault is fixed until it snows again.

Good luck finding a new dealer. Over the years, I have had no problems with any Fiat garage.

Mike O.

 

[doctorchris]

Apart from snow or ice, the only way you could test the 4x4 system would be to drive on mud or wet grass,can't help you to find that in Manchester though.

 

[Herts Hillhopper]

Can either of you two (DrChris and Mollybuttons) access the ePER system (Fiat parts catalogue) linked from the top menu of this forum? (as a Mac user, it only partially works for me and I can only see the first level pages).

You might be able to find the Cross rear diff there. Electropneumatic valves are generally a unit where an electric solenoid operates to allow air pressure or vacuum to move a control element, such as the actuator for the Diesel engine's exhaust gas recirculation valve. I wouldn't expect there to be a supply of air or vacuum* to be present in the rear diff. (*OK, pedants will argue you can't supply a vacuum... but it can still be controlled!)

Actually, this raises another option: is the rear driveshaft engaged and disenaged at the front end, I wonder? With the lesser 4x4, the shaft is always rotating even when not needed. Maybe the Cross controls the front connection (where the availabilty of engine vacuum is more likely) using a combination of vacuum system and solenoid valves?

Pete

 

[Herts Hillhopper]

How do you know when the Cross is in 4 x 4 mode ? It may be difficult to confirm whether the fault is fixed until it snows again.

When I recently had my tyres changes and the car was up on a lift (the sort where the wheels hang clear), you could see that the mechanical connection of the non-Cross 4x4 was working, because the front wheels turned (the opposite way as no resistance from the ground) as the mechanic turned the rears to line up the bolt holes.

So, if you really wanted to, you could check to see if the Cross does indeed only engage 4-wheel drive when needed by asking a friendly tyre depot to lift the car for you. If turning one wheel only turns the other on the same 'axle' (and in the opposite direction, owing to the complex workings of a differential gear, front or rear), this would give a probable indication that the 4-wheel drive is indeed only engaged 'on demand' by some electronic means (and also show that Fiat's sales blurb which says it uses only a viscous coupling is wrong)

P

 

[doctorchris]

I'm pretty sure that the Cross has a propshaft to the rear which constantly turns and enters the rear diff casing where selection of drive or no drive to the rear wheels is then decided. It is at this point on the rear diff casing that the 2 largish (about baked bean can size) canisters orientated laterally are found. These are not to be found on the 4x4 Climbing. I suspect that these are involved in coupling and decoupling the drive to the rear axle and may operate electropneumatically, hence the need for a replacement valve.