Grand c4 Picasso B174E MotorisedTailgate fault code

[jlmj2009]

Hey guys

Right, Ive had the car apart this Sunday morning. Bit of fun and games but I worked it out and only broke one clip! I lost a few, but luckily had some spares.

Some pointers in case others come across this thread:-
- Removing the plastic trim on the inside of the boot near the high level brake light is difficult, you need to give it a REALLY hard pull to get them off. I managed to work it out with an endoscope camera.
- I removed the plastic tailgate trim on the inside of the lower boot, fairly straight forward, but it is attached with screws at the bottom near the glass and to remove it, you have to remove the trim above to access the screws on each side.

I then removed the trim near the rear seat belt to access the earthing point MC63 >> No signs of damage or corrosion there either. I removed the nut to do a double check but all was good.

I checked both side of the weak point where the wires go thru the body/tailgate but no obvious signs of breakages (difficult to photograph)

I did find that the rear wiper hose was broken off (wife's car and she never uses it) - So whilst I was there I repaired that.

I've checked the rest of the wiring and all looks OK inside the boot, no signs of damage or corrosion that's obvious. There are some signs of water ingress (or something) near the wiper and that lands on the control module? Coincidence?

I'm going to disconnect the battery again then check all of the connectors one by one for any issues and do the BSI reset procedure in case that makes any difference.

After that, I'm tempted to get a second hand control module to see if that makes any difference because of the above....

FYI -- I cannot find the other end of the earthing point to try and run a (temp) new earth wire, the loom is covered in protective tape, so I'd have to remove that. It's also zipped tied in multiple places so I can't see how it would move out of place to get damaged.

Investigations continue but I also have the bathroom ripped out so conflicting priorities.....

[GiveMeABreak]

Please use the Full Editor & Preview button to upload your images directly to the Forum and place them as needed, it saves people having to navigate away to a third party hosting site every time (and also preserves the images for future).

My first thoughts are the water ingress that you discovered from the leaking rear washer pipe. That'll do it every time and I suspect water has corroded one of the pins or got into the circuitry and caused some corrosion. It may be worth carefully removing, opening, drying and and cleaning up with some electrical contact cleaner. If all goes well after checking operation and before reassembling the trim, I'd get some insulation tape and some plastic covering to try and isolate the unit where the connector is exposed in case it happens again.

I had issues with my parking assistance module an my C5 - a 5 litre container of berry scented screen wash concentrate came loose and emptied a lot of itself into my boot well via the carpet and into my spare wheel recess where the parking assistance ECU was bolted on. Had erratic behaviour and intermittent failures before it was discovered. Took me a few days of careful cleaning up and drying to resurrect it. Lucky it hadn't caused permanent damage.

[jlmj2009]

Thanks for fixing the links - I should have realised and will do this going forward.

Agreed, water ingress may well explain it. Fortunately, it seems the excess water from the rear washer was going down the side of the boot but I think the leak must be from the wiper arm. I was able to get a boot ECU controller for £20, same part numbers etc, so Ill put that in and see if it helps whilst checking all the connectors.

Ill keep the thread updated with progress. 

[GiveMeABreak]

You should be fine in that case - but I really would ensure there are no more leaks from the washer piping before reassembly.

[jlmj2009]

Quick update and some good news!

Had another look at this today after a reprieve from the bathroom. I disconnected the battery. Checked all the connectors to the motorised boot struts and to the ECU. Nothing obvious, so I replaced the boot ECU. Nothing obvious, no clear damage or marks to the original ECU. After fitting the replacement ECU (slightly newer model but same part number) I did the BSI Reset procedure and got the three quick beeps again when pressing the boot button on the tailgate

I started the engine to check all the indicators / rear reversing camera etc worked and they did. Good news! I then pressed the close button on the boot and to my surprise it worked. It now opens and closes on the fob and on the button press.

I'm not sure if it was the original ECU or the BSI Reset, but it's certainly working again. My guess was the ECU....

Wanted to send a huge thank you to GiveMeABreak and everyone else that helped out.

I hope the detail I've provided in this thread helps someone else in the future.

Have a good weekend guys

[GiveMeABreak]

Great news, thanks for updating the thread, it really does help others.