Technical 4wd not engaging

[John578]

Hi
I'm looking for some advice if possible. I bought a 4wd Panda (13 reg) in the summer and was looking forward to testing it out in the winter months. When the snow came a couple of weeks ago the rear wheels wouldn't enagage and it came up on the dash that "4wd unavailable". It had summer tyres on all round and the front wheels were spinning trying to find grip. I took it down to a Fiat dealership who told me that there's nothing wrong with the 4wd system and said that it failed owing to the fact that the rear tyres couldn't find any grip which then caused the clutch to start slipping which in turn then made the 4wd system unavailable. They tell me that winter tyres on all round will solve the problem as the rear wheels will then find grip when power is transferred to them and that the clutch will therefore not slip and make the 4wd system unavailable

Does all this make sense. I asked a few times if this would solve matters and they were adamant that winter tyres on all round means the problem will never arise. I have to admit I took some convincing and I'd be grateful for anyones thoughts.

 

[Panda IIs]

Hi, I've a 4x4 TA on '63 plate. How can the tyres possibly affect the 4x4 engagement? Imagine winter tyres on a slippery surface... no difference.

I think the system works automatically by transferring drive to the rear once front wheel "slippage" has been detected @Herts Hillhopper has previously posted some good description of the system on here and will perhaps join the conversation. You can force the 4x4 to engage using the switch on the dash I think it automatically disengages over 30km/hr to prevent damage to the system. This message maybe a symptom of low battery volts which plays havoc with this and other systems.

In the absence of snow do you have a nice loose gravel road you can try a swift pull away on? You will know when the 4x4 is working - great fun when it is on point..!

Sorry for the vague nature of this post I don't have access to the car nor its drivers guide to be more precise

 

[John578]

Hi, I've a 4x4 TA on '63 plate. How can the tyres possibly affect the 4x4 engagement? Imagine winter tyres on a slippery surface... no difference.

I think the system works automatically by transferring drive to the rear once front wheel "slippage" has been detected @Herts Hillhopper has previously posted some good description of the system on here and will perhaps join the conversation. You can force the 4x4 to engage using the switch on the dash I think it automatically disengages over 30km/hr to prevent damage to the system. This message maybe a symptom of low battery volts which plays havoc with this and other systems.

In the absence of snow do you have a nice loose gravel road you can try a swift pull away on? You will know when the 4x4 is working - great fun when it is on point..!

Sorry for the vague nature of this post I don't have access to the car nor its drivers guide to be more precise

Thanks for taking the time to reply Panda Ils.
Have to admit that I thought what you say about the tyres and did question the mechanic a bit but he wouldn't have it. I said that the power wasn't going to the rear wheels and about the message on the dash. His answer was that the clutch slipping caused the message on the dash and that he's tested everything and says the 4wd system is working as it should. So his answer is to make sure the rear wheels have maximum traction when power is transferred, thus avoiding the clutch slipping and the 4wd becoming unavailable. I'm putting winter tyres on anyway so it does little harm to try out what he says.
For point of interest when the 4wd unavailable came up I couldn't engage the ELD but I can now so maybe the mechanic has a point about making sure everything is in place to avoid potential clutch slipping etc.
I'd tried it out on gravel before the snow/ice came and like you say it pulled away swifitly and you could feel it engagaing.
Just need some bad weather now!
Thanks again

 

[Herts Hillhopper]

Hi @John578 and @Panda IIs - I will indeed join in

I very much doubt that tyres will make any difference. It is the spinning of the front wheels that causes the system to engage, so suggesting that the rear wheels failing to grip is 'not correct'. (However, cold weather/all season tyres will offer more grip in mud or snow)

The system is engaged by a solenoid on the rear diff casing. This is energised either when either of the front wheels starts to spin and loose grip, or if the '4x4'/ELD button is pressed on the dash (or, in the case of a 4x4 Cross, the mode dial is turned to 'off-road' - has same effect and turns on permanent 4x4 mode).

There have been many posts here in the past that seem to point to a failure of that solenoid or it's control from the ECU causing that message. However, I have a hunch that it is also (like many other electronic sensors and controls in the car) affected by a low battery voltage, as it appears to draw quite a current briefly. If your 2013 Panda is still on its original battery, my first suggestion would be to replace that before looking into anything else.

It is also possible that if the solenoid has not operated for a while, that it, or what it connects with, may have seized. Another recent post here asked if 'exercising' the 4x4 system now and again was a good idea, which I replied to saying I thought it was. My car gets used on muddy fields etc quite frequently so it probably turns on by itself anyway (you really can't tell when it does -- there's no light or messages to tell you when it automatically engages -- but it clearly does as otherwise I'd have been stuck )

As to 'engaging the ELD' - again, your mechanic may not have understood. Pressing the button does not 'engage' a mechanical lock. In fact, it does't engage anything at all. All it does is turn on an extra bit of the ABS electronics, so that if any wheel, front or rear; is detected as spinning, then the system will apply the brake to that wheel, stopping it spinning and so allowing the differential to drive the other wheel on the same end of the car.

The dealer may have put the car on a lift and tried turning a wheel. This will always make all the other three turn owing to 'friction' in the drive mechanism when there's no weight on the wheels. This is why the system is described as normally delivering 98% of the drive to the front wheels. Really, the only way to test is to put all the wheels on rollers (or a wet grassy field!) and force one front wheel to spin.

Check that battery first, then report back to us...

(Also, have a read here: https://www.fiatforum.com/threads/4x4-awd-not-available-what-might-be-the-cause.480389/post-4539421 -- this went on to be a very long conversation but the links in my post (the one that link goes to) should help)

Pete

 

[John578]

Thanks for your detailed and comprehensive reply Herts Hilltopper.
You have definitley convinced me that the mechanic hasn't diagnosed the issue. Was a bit disapointed that Fiat dealership are saying this to me and like I said he wouldn't have it that it was an electrical issue. It's just cost me his time and I was geting winter tyres anyway so no harm done.
I'll take your advice and get a new battery...could well still be the original. If that doesn't remedy matters I guess it's the solenoid or what it connects to.
Thanks once again for taking the time to respond and likewise Panda Ils.
I'll update you once I've got a new battery and the weather gets worse...there's no way of testing it out before then is there? Don't want to chance getting stuck in a field!

 

[gar074]

You can test it by attempting a quick getaway on any loose or slippery surface (eg, gravel, or a wet/greasy road), but it's not easy to detect whether the drive to the rear wheels is engaged unless you know what you're looking/listening for (which of course you may not, if yours hasn't been working properly since you bought it).

It's hard to describe, but the car kinda squats down a little at the rear, and then takes off like a scalded cat.

I agree that the mechanic's explanation sounds like BS. Slipping clutch my @rse!

 

[Panda IIs]

You can test it by attempting a quick getaway on any loose or slippery surface (eg, gravel, or a wet/greasy road), but it's not easy to detect whether the drive to the rear wheels is engaged unless you know what you're looking/listening for (which of course you may not, if yours hasn't been working properly since you bought it).

It's hard to describe, but the car kinda squats down a little at the rear, and then takes off like a scalded cat.

I agree that the mechanic's explanation sounds like BS. Slipping clutch my @rse!

Totally agree @gar074 You know when the 4 wheels are driving, you get that hard-to-describe push in the back from the drivers seat rather than the front end just rising up. As you say it kinda squats down and surges forward - love it. One day when I've made my millions I'm gonna try adding Arbarth bits just to see; you understand..?

 

[Goudrons]

Have a look at this thread.

panda 4x4 not working | FIAT Panda (2012+)

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...

www.fiatforum.com

There have been very few problems reported with the 4x4 system, but some have had problems with the wiring to the electro pneumatic valve or the valve failing totally due to water ingress.

As you're getting the unavailable message I very much doubt the problem is with the tyres, there's a electro/physical fault somewhere.

You could as a quick test.
Find a wet bit of grass and turn on the ELD and floor it from a standstill.
The green "4x4" locked axle symbol light in the dash clock (speedo or rev counter can't remember which, but I think it's the right hand clock) should flash when the ELD is active.

With the ELD turned off, pulling away sharply on the road should as described above, cause the back to squat a little, you should feel the back end nip up and shove you forward.
With all four wheels driven and under load, it might also feel a bit baulky when changing from 1st to 2nd, like it really doesn't want to be rushed.

 

[dkyr]

I had a similar issue... on a difficult terrain the 4x4 didn't engage without having any alarms about 4x4 malfunction. When i tried to force it using the rotary dial (Cross model) it gave OFF ROAD UNAVAILABLE and after that every time i switched the engine on gave me the same warning. Brought it to a specialist who after checking the mechanical parts and the removing the solenoid from the rear diff (was OK) he concluded that the problem was the rotary dial - we sourced a new one from FIAT put it in place and now everything works flawlessly

 

[Herts Hillhopper]

I had a similar issue... on a difficult terrain the 4x4 didn't engage without having any alarms about 4x4 malfunction. When i tried to force it using the rotary dial (Cross model) it gave OFF ROAD UNAVAILABLE and after that every time i switched the engine on gave me the same warBrought it to a specialist who after checking the mechanical parts and the removing the solenoid from the rear diff (was OK) he concluded that the problem was the rotary dial - we sourced a new one from FIAT put it in place and now everything works flawlessly

That’s an interesting one: but sort of relates to the ‘exercising the system’ comments: the dial is just a switch. In the Cross, the ‘normal’ setting is basically the same as the (non-Cross) 4x4 with no buttons pressed (leaving the car to decide automatically). It’s possible the switch contacts might get dirty or corroded? Same with the 4x4, where pressing the ELD button behind the gear-lever selects the same ‘off-road’ settings as the dial in the Cross - and they too might corrode? The point here then is that ‘exercising’ the system would have the effect of exercising the switch too? No harm in doing this now and again, maybe?

 

[dkyr]

If i understood correctly from the specialist the rotary dial is part of electrical circuit that drives the solenoid so if broken/malfunctioning there is no "continuity" in the circuit so the solenoid can't be "driven" by taking commands from ECU/ESC/ELD, etc...

 

[Marcus Daly]

And it’s pretty pointless anyway.

 

[Michaelfly]

Make sure all 4 tires are the same size and brand to. This can cause huge problems