Citroen C4 Picasso Not The Usual Boot Problem.....

[ChrisPembs]

Hey

Hoping someone can offer some next step pointers, so, I have a 2010 C4 Picasso, out of the blue the boot refused to open, did some research saw the usual suspect is the handle switch so I took it out of the car, dismantled it all very simple it really is just a switch, it was clicking fine and appeared to be ok so decided to jumper the connector and even with a jumper the boot still would not open which now kind of make me think the switch is fine and the problem is elsewhere.

Is this one of those situations where the handle wiring feeds back to the BSI before it instructs the locking mechanism to release or is it a direct communication between the handle and the locking mechanism? If so then surely it has to be the mechanism itself? Any way to test do you think? If it does feed back to the BSI first what would you suggest? Any known issues with frayed wiring or anything else?

The car is used for work for a cleaning business so a none working boot is more than a pain, sods law ha ha ha, I have rigged a wire to the manual release mechanism for the moment which you yank from the back seats., it works but is a bit of a pain so am keen to get it working properly asap.

Any help / wisdom very appreciated so thanks in advance

[wheeler]

The switch sends the signal to the BSI then the BSI opens the latch. If it operated directly off the switch it would make the security very weak.
First thing to check is for damaged wires in the rubber boot where it passes between the body & bootlid, a very common break point due to the constant flexing.

[ChrisPembs]

The switch sends the signal to the BSI then the BSI opens the latch. If it operated directly off the switch it would make the security very weak.
First thing to check is for damaged wires in the rubber boot where it passes between the body & bootlid, a very common break point due to the constant flexing.

Hi, thanks for the reply and apologies for the late reply from me, been away for a couple of days.

Had a feeling that might be the case with the BSI, so, in theory then if I connect a multi meter to the connector that goes on the back of the lock mechanism and then press the button to release, if all the wiring is in tact I should some some voltage meaning it will be the lock mechanism itself but if I see no voltage then it must be a wiring break or other issue along the line, am I thinking in the right direction? I have checked already in the rubber boots around the boot are and all the wires appear to be in perfect condition, no obvious breaks or even light damage.

[wheeler]

On the 3 pin connector on the latch mechanism pin 2 should have a good earth & pin 1 should get a breif 12v pulse when you operate the tailgate switch. Pin 3 is the boot open switch signal wire.
If the pin 2 earth is ok and you apply a brief 12v to pin 1 it should unlock the mechanism.
Do you have Diagbox or Lexia? you can easily check the operation of the switch & latch with this too.

[ChrisPembs]

Hi

Thanks for the tips, much appreciated

No Lexia or Digibox yet, I need to do another forum post to figure out what the best most complete kit is to buy today, tons on Amazon and Ebay and no real idea which one is best, I need one to unlock the AUX channel on the stereo so I can install my Echo Auto lol

[ChrisPembs]

Just a quick update, so far not done a thing about this, was still using the wire I attached with great success lol then the turbo started to whine, currently in an RAC hire car with new turbo being fitted later this week, about to start searching for a Lexia setup now. Will update as I progress.

[Mandingo]

If you have the Three button remote with the middle button showing the boot open icon, a long press should open the boot.
Currently my 2015 C4 is playing up with intermittent engine warning light and occasional boot opening failure. I'm going to replace my switch and see how it goes. i've already repaced the rubber cover some years ago, so hoping it's just mechanicle failure. I thibk I will check the cable as well to see if it shows signs of breaking.

[Andreiva]

Hi, have you found the issue in the end? I am troubleshooting the same thing for my C4P and while the boot button doesn't seem to work shorting it's connector doesn't seem to open the boot either. The actual lock seems fine (I connected 12v on pins 1-2 and it did work) so the last thing would be the wires from BSI to it but at least the ones in the rubber grommet seemed fine so I am stuck.

[Richard_C]

I remember intermittent issues on my C4 picasso, lock making all the right noises but not unlocking properly. Maybe I was lucky, but clean and a thin smear of vaseline on the fixed part of the latch on the boot floor sorted it. Maybe the unlock motor doesn't have much oomph and maybe in winter the door rubbers are harder and stiffer so it sticks. But free to try if it sounds like everything else is working.

[Andreiva]

Thing is based on my troubleshooting it seems it's a problem between BSI and the unlocking motor/mechanism since it doesn't make a sound no matter what. Even a Diagbox actuator test doesn't make it do anything. My current idea is either a fuse which seems strange to affect just this one thing or a wire break. But both seem extremely annoying/hard to troubleshoot further.