Technical 4x4 AWD not available / What might be the cause?

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Technical 4x4 AWD not available / What might be the cause?

BlackForest

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Hi there,

I am a newebie on this forum. I am a hunter from Germany and use a Fiat Panda 4x4 for everyday use in town and in the mountains. It is the only car I have, it is also the shared family car (half a dozen users).

Nice car, which fits my philosophy "as small as possible, as big as necessary".

IIRC car is a 2015 build.

Now I realized that the awd is no longer working. Had in my independent garage the oil checked and filled up 0.6 liters. They did not see any errors with their OBD-System.

Next did research the internet and found one and only one resource where it seems that knowledge is available: This forum. That is why I am kindly asking you for your advice.

Plugged in my Multiecuscan did a reset of the (indeed existing) errors, did a diagnostics ran (see attached report.png) and reproduced the "AWD not available" error by engaging a steep slope. This gave me the errors as detailed in the attachements.

The actuator test of the solenoid ran without errors. There was also a clicking audible when switching the solenoid on.

Still running the first battery. Had a few times the effect of a poorly performing engine, which I associated with low battery (starting the engine with the screen heating, seat heating, fan etc. on). Restart with no electrical devices switched on did always cure the prob.

Any ideas?

Thx,
David
 

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Hello and welcome to the forum. Great car choice ;)

My first advice for any Panda where you've even though the battery has a problem is replace the battery now. They throw all kinds of strange faults.
 
Hello,

Thx for the input. Did gather some data to see wether this all correlates with the batteries voltage.

Also included the perspective of the ABS Controller, as (IIRC) in another thread Oyumurtaci did mention the voltage and the ABS as one of the possible sources of trouble.

Overview of the ABS is given in abs9resp.png. Did observe the Traction solenoid valves and made the actuator test (hitting F10 Execute, see solenoidErr.png). While testing they went into an error state, also on the picture they are OFF.

The test created the error C1222-29 - Vehicle speed incoherence. Never captured this before or after.

Next I did reproduce the situation of the diff engaging in the slope (ELD enabled). See SlopeErr.png. The red rows show when the front wheel starts spinning and the voltage takes a deep dive - I have the impression that there is a moment of drive from the rear axle, not too sure about that - and finally the 4WD is switched off. BTW, during normal operation on the road, the 4WD is activated every once in a while during acceleration WITHOUT any noise. But after this test the "usual" errors C2007-92 - Clutch system and C2000-98 AWD system overtemperature are captured.

As far as I can see, the statement "AWD system overtemperature" is a guess of the software, as there is no feeler to take the temperature on the rear diff.

To get a feeling, wether the ABS is responsible for the drop in voltage, I did test the ABS.

First same scenario as for the clutch coupling perspective, engaging in a steep slope to get the front wheels spinning. (See SlopeABSErr.png). When the front wheels start spinning at row Second 13.04, the traction solenoid valve reports an error. In contrast, the ABS controller does NOT see the drop in voltage. Strange.

Next I did an plain ABS test by hitting the breaks violently (see ABSError.png). Indeed, when the ABS is engaged (you see the wheel speed getting chaotic) the the voltage drops.

Well, not clear what I see, but I guess next step will be a new battery.

Any advice wellcome!

Thx,
David
 
forgot the photos
 

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Hi again. I know it doesn't necessarily make sense but get a new battery. These cars (and the previous version) throw many strange faults with the slightest battery fault. Many of them make no sense but a new battery solves it for very little cost & trouble.
 
I agree voltage drop under load is a big problem. Battery replacement is a good idea together with checking battery leads and battery ground connections.
Plus check alternator is giving correct output.
Good luck (-:
 
It is almost certainly caused by low battery voltage (assume car seeing little use at present). May not need a *new* battery, just needs to get up to full charge. Unless you've been parking it in the sea, the chance of alternator or earth connection faults is slim.

Here in the UK we are still only allowed to use a car to travel to 'buy basic necessities' (that's the wording in the law, it doesn't say 'essentials'), or to travel to work or a medical appointment. Otherwise our cars should be parked, locked, and looked at longingly, like mine that's moved once since 23 March...
 
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Wow, those wheel speed readings are wild!

Unfortunately, since the AWD system works as a function of the ABS system they're all tied into each other so diagnosing the problem can be quite difficult. The solenoid draws a lot of power for a brief period when engaging, but it also gets easily confused by wrong wheel speed readings, which can also be caused by low voltage which is what the solenoid causes in the first place. And so on and so on, so it all goes around in a circle.

I'd start from the simplest first (battery, check wiring for unusual draws and grounds).

While this would be quite unusual I'd also make sure the mechanical elements of the car are all working (correct wheel sizes, wheel hub bearings, driveshaft CV joints, the bearings for the AWD driveshaft, look for leaks or weeping on the rear differential) and possibly flush the differential. Yes, it is supposed to be a "closed" system and lifetime fluid, but Fiat themselves were wise enough to put a drain plug and fill hole on it which means they themselves weren't exactly confident about it. Mine required a slight fill at 50k kilometers and the fluid was in good condition, but if the clutch pack in the rear differential is worn then all the debris will show up in the fluid.

Lastly, the most difficult way to trace the issue is the electronics because even if we know the errors, like I said it's all so interconnected that the actual source may be somewhere else. So far, low voltage seems likely. If a new battery doesn't fix it check the alternator and the belt for it again. From there on it will end up being trial and error with wheel speed sensors and ECU connections and solenoid voltages and so on until something works. Unfortunately we don't have a workshop manual for this series Panda yet, so fixing things ourselves is always a learning experience.

Edit: Something that I thought of after posting, is the actual gearbox clutch and slave cylinder in good shape? If, for example, it gets overloaded when drive is sent to the rear and starts spinning it could be overheating and disabling everything else.
 
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Hello there,

thx for all the input!

Unfortunately, problem is still not fixed.

What did happen in the meanwhile?

B. My garage did drain the rear diff. No debris whatsoever but lack of oil. Filled up with 0.6l - to no avail :-(
The solenoid looks good and is actually working.

A. Myself, I did replace the battery - to no avail :-(

If I go to the ABS-ECU and manually activate the Valves, all of them are working but end up in an error condition.

The live test in the slope yields the same as before - wheels go spinning ESC / ELD jumps in and off goes the AWD: "AWD mode not available"

What are the next steps?

Well, basically what you did suggest.

A. We are going to the electrics before the electronics.

What does this mean? The ECUs (five are detected by the MultiEcuScan) report all a different voltage on there high voltage pin. To my understanding they measure the voltage between this high voltage pin and their respective ground pin. Each and every ECU has its own and very private reference base (I stand to be corrected on this one!). I will take note of all five readings with the engine running hence (hopfully) certeris paribus. This reading is electronics.

We will measure the value between the respective high voltage and ground pins to see wether indeed there is a different voltage. This is electrics.

Might be that already there is a difference to be seen, then we can measure the resistance (actually the voltage from which to conclude on the resistance) before and after the ECUs with low readings.

This would be a fast gain. Some erroded contacts or the like.

B. If A did not deliver the lucky punch, we will do in the MultiEcuScan the actuation of the valves on the ABS (which gives an error) and in parallel measure the voltage between the high voltage and ground pin of the ECUs to see wether this shows a significant reduction. Might be that at this point we already have to take an osci instead of a multimeter ....


The approach of the garages of the official Fiat Germany approved dealer "replace everything one by one and make the customer blead for it" is IMHO not the way to go.

But I feel fear that we will end up in trying to identify by trial an error the component that is creating havoc much like oyumurtaci suggested...

Thx for your assistance so far!

David
 
It would seem that the solenoid is receiving an instruction to operate, and may even move, but that it is not actually engaging the 4x4 system. I do not know what it does to make this happen: it might mechanically move a lever inside the rear diff? or it might open a valve to allow fluid to go somewhere? If the garage want to start to change parts, my guess would be to change that solenoid first.

Note: if the car goes into auto 4x4 mode correctly, you do NOT get a light showing in the car. If the ESC and ELD lights both come on, that is indicating a fault with the selectors.

IF you press the ELD button to 'force' 4x4 mode, the light in the switch comes on to show you have pressed it, and then a green light in the dash shows that you are in 4x4 mode. If the ELD operates to stop a wheel spinning the yellow ELD light will flash briefly as well (but only while the spinning wheel is being 'held' by the brakes... it does not stay on).
 
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Hello,

me and my persistent problem again ;-)

The voltages as seen by the ECUs themselves and reported by MultiEcuScan here attached. As you can see everything is at the low end but still fine. Everythin? No, wait, the Body Control Modul reports nonsense.

Whatever might be the reason, I am facing another problem. My gargist has no electric circuit diagram and hence can not do any "electric" measurements :-(

What he found is, that the generator only produces 12.8V. A little low. And as I already have recorded voltages high as 14,77V it even seems to be instable.

Another observation is, that the Body Control Modul did report 82% load state for the old battery - and for the new one as well.

So next step will be to replace the generator.

Does anybody know where to get an electrical circuit scheme of the car?

Thx,
David
 

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Generator/ alternator voltage appears very very low at 12.8 volts, fingers crossed it is not an ecu controlled output alternator and replacing it will cure your problems.
I'm thinking low voltage and or low battery/faulty battery could cause the problems you are having. Possibly if voltage drops below a certain value the 4x4 system shuts down.
If voltage starts above shutdown value , then 4x4 system tries to work putting extra load on electrical system, voltage may then drop causing 4x4 to shut down.

Thanks for keeping us updated, I'm very interested .

I don't know where to find wiring diagram.

Bernie may help.
 
I've not monitored the running voltage from the Panda alternator, but there are many cars that vary voltage significantly dependent upon load. Our 2003 S2000 failed to start once with a flat battery, so I was suspicious of the alternator and monitored it for a few days. Plus 14.3v when needed, but drops to well under 13v when not required. When I first connected the voltmeter it was in 'not required' mode which made me prepare to order a new one.... Turns out this was not necessary and in fact the car had just not been used much, so just needed charged properly. Live and learn.

Maybe Panda is the same, so I may monitor when I get back to using the car more regularly - particularly as I now have MES on iOS and can run it routinely. (y)
 
Guess you are right.

Have a look at the voltage dip the Coupling Control Module reports when it switches off ...
...and...
... at the same time the action the ABS initiates: Nearly All valves (8 ABS, 4 Traction control) plus the pump are spinning off at the same time!

Data is recorded when the ELD is off and hence the ESC jumps in when stability is lost due to front wheels going nuts...

I am so curious. Generator will arrive next week... stay tuned ;-)
 

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Measuring the output the electrician way with a voltmeter while riding the car is not possible with my equipment. Plus I ignore the mimik of the voltage regulation on the alternator. Would join the guess that it is not ecu-controlled.

What I can and will do is recording the CCM while riding the car this evening on a mixed trip (motorway, overland roads, city) for about 120km with the MultiEcuScan. At least I have then the "electronic opinion" of one of the involved ECUs about the voltage suplly in the system.
 
A quote from
Didge3 regarding twinair alternator.. poor battery

'29-04-2020

Yep seems battery related. I have an OBD gauge as a permanent setup in the car which shows oil temp,*mapsensor and voltage. Usually the battery is charging at 13.6-13.7v (this is normal on a TA, they have a ‘smart’ alternator which varies output dependant on charge), jumping up to 14v when cruising or 14.5v coasting.*
This has been a constant ever since I got the car but today I kept an eye on it on a 20mile trip and the entire journey it was charging at 14.3v, it’s never dipped below that so I’m taking that as the car seeing a low state of charge...'


I have seen similar on my 2012 punto TA

I use a plug in cig.socket gauge.. behaves 'normally' on older mj diesels..

But in the TA it does indeed shift charge on load..not revs

Your output seems 'wrong' :eek:

But a basic test meter across battery poles should confirm if a charge is being performed ;)


On older alternators.. the battery output regulator.. and brush pack were a 'bolt.on' component.. less cost ;)

Charlie
 
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Can't help with the 4x4 stuff but battery monitoring is a bit awkward for Twinairs, the voltage will vary with load and the state of the battery charge. Rule of thumb is you should see the highest charging voltages when decelerating in gear and sub 14v charging at idle or cruising if the battery is 'full' and in good condition. Seeing a voltage higher than 14v during idle or cruising would indicate a 'low' battery or a battery potentially going bad.
 
Seeing an across poles voltage of 12.8v
Says .. 'nothing from alternator' .. to me :eek:

Tricky to assess charging voltage properly, as the alternator only really provides charge when the car is on the 'overrun' (going down hill or decelerating) -- you'll notice this when driving as the heater blower goes faster if you lift of the accelerator. Part of the Euro 6 set up to save fuel - so-called 'smart' or regenanerative alternator, where the output voltage from the alternator is controlled by the engine ECU, reducing the load on the engine from the alternator while accelerating and increasing the output of the alternator under no-engine-load conditions.
 
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