Technical Fiat 500C Roof Reset Problem - I've run out of ideas

[ricky76]

Hi. So we took on a Fiat 500C from a family member which had a broken roof. From peering between the headliner, I originally thought it was just the tension strap clasp on one side which was broken, so I replaced that with a new part and when I operated the roof, there was a load of crunching. On closer inspection when stripping the roof apart (thanks YT), I found that lots of the plastic parts attaching the roof to the runners were broken. So I bought a 3D printed replacement kit off eBay.

After a couple of days of work, I managed to get all the new plastic bits fitted, and have got the car back together again. Thankfully there was no damage to the runners, and moving the roof back and forth seems pretty smooth to me.

However, I can't give myself a pat on the back just yet, because I am unable to open the boot, and I have tried the reset procedure many times for the roof, and I just can't get it to work. The roof goes back and forth just fine, and is not impeded. From closed, ignition on, I am holding the open button down until it reaches fully open, and then wait 3-5 seconds, before letting go. I then hold my finger on the close button until it is fully closed, but it isn't triggering the Fiat cycling procedure to re-calibrate. Instead, it seems like the roof is repeatedly trying to move forward with nowhere to go, making a sort of stretching taught sound coming from the rear.

I have loosened off the tension straps to no avail (and if anyone can advise me on how tight they're supposed to be when the roof is closed, that would be great because I can't find any instruction or advice anywhere on the web).

I've charged the battery, have locked the car and reopened it, tried it with just the ignition on and with the engine running, made sure all the doors are closed, etc.

I managed to get the procedure to run on one occasion - it didn't make the same noises when closed, and cycled through the procedure. However, the roof still didn't operate with the 3 positions afterwards, and the boot wouldn't open.

A very frustrating end, to a couple of longs days, and what was seemingly a good result until the final hurdle!

I'd be very grateful to hear from anyone who has fixed the same problem, or knows how to. Thanks for reading.

 

[ricky76]

UPDATE: I've tried removing the fuse to see if that helps, but it didn't. I also let the tension off the straps and that doesn't help either. I have bought a copy of Multiecuscan and have used it with a USB OBD2 cable from ProScan (a modified one) with a yellow adapter cable. I can change service data and other things using the software, so I know it is communicating. However, when trying to do a hood initialisation in the software, it complains that there is no communication (or something along those lines, as I did that yesterday and can't remember precisely what it said.

 

[Derbyfella]

out of interest have you cxhecked the wiring loom in the hatch?
obviously the boot can be opened from inside.

also when you say you have locked the car and re-opned it do you mean with the remote? Ours i seem to recall sometimes did this....and i had to manually lock and unlock the car then start...

 

[Derbyfella]

also are you following this relearn procedure

500c boot not opening (2012 1.2 Pop) | FIAT 500 (2007+)

Wife has just told me that her boot isn't opening. Doesn't work on key fob or the handle/button although handle does move....apparently its been slightly slow to open on occasion over the past couple of weeks. So is this likely to be gunk in the handle and switch mechanism or a slightly...

www.fiatforum.com

IM sure ive seen a slightly different one

 

[ricky76]

out of interest have you cxhecked the wiring loom in the hatch?
obviously the boot can be opened from inside.

also when you say you have locked the car and re-opned it do you mean with the remote? Ours i seem to recall sometimes did this....and i had to manually lock and unlock the car then start...

Yes, I opened the boot from the inside so that I could remove the boot lid when working on the car to remove the roof. I put the boot lid on a workbench, rather than unplug and feed out all the wiring. And a point of interest, the boot would work fine despite the broken roof. When I replaced a broken tension cord clip previously, and tested the roof to find that it snared up and had other bits broken that needed to be replaced, the boot wouldn't open from that point on. I guess the module thinks that the boot is either open, or has received a signal to suggest the roof is broken which stops the boot from opening as a safety measure.

I have locked and unlocked the car using the remote mainly. Although based upon some other comments and yours, I have tried just using the key prior to the reset procedure, and that makes no difference unfortunately.

 

[ricky76]

also are you following this relearn procedure

500c boot not opening (2012 1.2 Pop) | FIAT 500 (2007+)

Wife has just told me that her boot isn't opening. Doesn't work on key fob or the handle/button although handle does move....apparently its been slightly slow to open on occasion over the past couple of weeks. So is this likely to be gunk in the handle and switch mechanism or a slightly...

www.fiatforum.com

IM sure ive seen a slightly different one

There is a slightly different one I have tried, and this one too. Neither work, and I have tried varying the number of seconds I am pressing the buttons, having the car running and not, etc.

There is of course the one time it worked, and the procedure initialised, but it didn't reset it.

Some people have described the clicking when the roof shuts, but I would probably describe it as the motor trying to repeatedly shut the roof with the sound of tension in the rear of the roof (probably the metal mechanism wires tensioning up) and a stretch. Keeping the finger on the close button just causes the motor to do this over and over.

 

[Derbyfella]

Can you post a video?

 

[Piccolo Nero e Bella]

Have you tried it with the pop-up deflector locked down? I imagine you have but there doesn't seem to be anything else there that might hinder its movement. Mine operates much more quietly with the deflector locked down.

 

[ricky76]

Can you post a video?

Here you go:

 

[ricky76]

Have you tried it with the pop-up deflector locked down? I imagine you have but there doesn't seem to be anything else there that might hinder its movement. Mine operates much more quietly with the deflector locked down.

Yes, I've tried it with the deflector up, and locked down. It makes no difference to the reset procedure unfortunately.

 

[Derbyfella]

WOW

that sound at the end is horrible.
I suppose its obvious to say that the car doesn't think the sunroof is closed properly.
What sensors tell the roof its open or not open??

 

[ricky76]

WOW

that sound at the end is horrible.
I suppose its obvious to say that the car doesn't think the sunroof is closed properly.
What sensors tell the roof its open or not open??

Yeah, it doesn't sound at all great does it. I'm a bit concerned that it might cause some motor damage the more I try the reset procedure. There was no indication of any faulty sensors or modules before the roof was repaired, which is why I was hoping that a simple reset procedure would do the trick. So I guess I'm going to have to spend some time doing some further testing.

I don't know what sensors or switches there are, or how to test them. So I'm hoping someone here might be able to advise me on that. I also have Multiecuscan software, so it would be handy if someone could give me some guidance on how to use it to test any switches or sensors, and the roof module.

 

[ricky76]

Not sure whether it's connected, but I noticed that the rear window drops quite quickly once the roof is almost fully open. It looks as though the sliders which are supposed to lock in some way, or hook into the mechanism, aren't. Maybe connected to the wider non-reset problem?