C8 triple sunroof - Solved

[MixerFistit]

This is probably one for the experts as it has PSA quirks all over it:

Can someone please explain how the sunroof control modules work with the BSI (and lexia)?

Only the centre sunroof works and only centre and rear have clicking relays so I did a bit of fault finding.

The relay has failed inside the module on the front one, when I cut the plastic of the relay I can see the wires have broke on the coil so maybe lucky and just need to solder a new one.

The switch on the rear sunroof had corrosion from an old water leak but looks fixable.
So I thought, well it's best to have front and centre working so I took the module from the rear and put it on the front.
The problem is, the front one (formerly rear) refuses to exit the safety creep mode. I went in to Lexia and there is no communication with the sunroof ECUs (although the centre one works as expected).

I can see there's a unique hex or alpha numeric code on each ecu so I tried removing them from lexia and adding them back under the BSI section hoping that this would somehow reestablish comms but no luck, also did a BSI reset.

So is it possible to program the ECUs to their correct locations so that they're recognised or is the front ECU a master one that always has to be in front and that's why Lexia can't even see the centre ECU anymore?

I don't want to buy a new module (if I can't repair) unless I know it's definitely going to be compatible in it's location and/or programmable somehow

And just to clarify, before I swapped about I had full comms on lexia, I haven't swapped back to see if it restores comms as wanted to ask the more knowledgeable on here first.

[GiveMeABreak]

Just be aware that there are different networks controlling the sunroofs, VAN CAR 1 & VAN CAR 2. There are 3 control units and 3 switch units, but 2 of the 3 separate switch units are the same with the other (6817) being different.

Key:

Single arrow: Wire connection
Triple arrow: Multiplexed connection

Components

BSI	Built-in systems interface
CV00	Switch module at the steering wheel
6120	Rear electric windows locking switch
6800	Sunroof switch
6817	Sunroof front switch positions 2 and 3
6818	Switch for sunroof row 2
6819	Switch for sunroof row 3
6830	Control unit for sunroof
9030	Front LH door station

Connections

N°	signal	Type
1	Switch lights up if movement authorised	filament
2	Position of the sunroof	VAN CAR2
3	Central closing of sunroofs on locking of doors and tailgate	VAN CAR1
4	Deactivation/authorisation of the switches for sunroofs rows 2 and 3	VAN CAR2
5	Deactivation/authorisation of the switches for sunroofs rows 2 and 3	filament
6	Vehicle speed information. Request to close the sunroof from the remote control. "night driving" mode lighting control	VAN CAR2
7	Sunroof closing and opening request	filament
8	Sunroof closing request	-
9	Sunroof opening request	-

[MixerFistit]

Thanks Marc,

So it looks like the modules (6830) are the ones I've found in the roof lining and contain the relay, and they are all the same.. if I'm understanding it correctly.
It seems it could all be heavily dependent on each part so I'll just swap the relay for now and put modules back where they were originally and see if comms are restored.

With regards to the CV00, is this for certain models? I don't have steering wheel controls for it, or does it mean something else?

[GiveMeABreak]

No CV00 is referring to the control unit inside the steering mechanism underneath the steering wheel, often called the 'Comms' unit. These are different for each vehicle and further differ on electrical architecture and equipment / options. They are what the indicator, cruise, audio and wiper stalks fit into (depending on vehicle and build date as to which type you have).

The only function that CV00 has is for the auto closing function of the sunroof on locking and for deactivation of switches int he rear (for the kids).

[MixerFistit]

Ah that makes sense.
I'll dust the soldering iron off in the morning and hopefully make some progress (for once!)

[MixerFistit]

OK, a quick little update.

Returning the controllers to their correct positions has brought back the comms in Lexia.
I soldered in a new double relay for the front controller and it's working great*.
Also repaired the rear switch by repairing the PCB track.

My only issue now is that both Front and Rear sunroofs have their antipinch triggered at regular intervals unless I double tap it in short bursts or assist with my hand. Otherwise it'll attempt to autoclose but then fully open regardless of how far it gets. Once it gets to the tilt stage it works fine

I've sprayed AC90 in the runners as a quick fix attempt but there's no difference.
Could it be the motors themselves? I'm assuming these antipinch work by sensing current spikes as the motor's work load increases.
I've popped the white plastic "gear"/decoupler in on the front motor and when operating with the roof disengaged, I can hear an uneven whirring that seems to increase at similar intervals to when the reverse gets triggered. Operating the motor as if to open sounds much smoother.

Is this a known issue? I don't want to go opening a possibly unserviceable motor that turns out to be like a Swiss watch with springs going everywhere if no need.

In a possibly related issue, my sliding door windows do something similar. If partially open, a closing attempt will cause the antipinch to trigger and it'll reverse, but once they fully open they happily fully close

As I sent this I was double checking and just noticed it seems to be an alignment issue on the windows. The window jumps very slightly to the rear of the car. If I quickly tap the windows I can see it straightening up and then it closes normally. Fully opening must reset the position. Will have to tighten the clamps on the glass maybe. So it's just the sunroof mystery for now.
I'll leave the window bit in, in case anyone ever finds it useful

[GiveMeABreak]

You need to inch the sunroofs closed in small manual operations until they are closed, then hold the button for a few seconds until it makes a very feint click. This reinitialises the anti-pinch and may need doing each time power is removed like a battery change - Ditto for windows with anti-pinch.

[MixerFistit]

The antipinch is initialised, that's what's causing the problem unfortunately.
It actually works better without antipinch as I can move it forward in bigger increments rather than having to tap the buttons to trick it.

I can deinitialise AP by making it lose its bearings by pressing the button while the motor is decoupled a few times so it reverts back to safety/creep mode. But once I've initialised the AP, something is causing it to trigger. I just can't see what the hell is causing it.
I went ahead and took the motor off and as far as I can see it operates smoothly. There is a large brass screw that was pushing against the internal worm gear that now that's been adjusted slightly I get a little more movement before it reverses but it'll still reverse consistently. I'm not sure of the actual purpose of this screw though, maybe to keep consistent pressure of the worm gear on the gear it drives.

Also these sunroofs don't open far do they, about 60% until it reaches the rear stopper, I guess the 3 windows are so close together it has to avoid a collision with its neighbour. I'm gonna have a job to let the family stick their heads out the roof next time I'm on the motorway lol

[MixerFistit]

Disassembled the motor completely and cleaned and regreased all of the gears.
There's now only one point almost at close where the pinch gets activated and that only happens about occasionally and it's at the point where it collides with the sprung wind deflector(?). It's a fairly strong spring so that slight increase in workload must be enough to trigger Anti-pinch.

I'm happy I'm on the right track (no pun intended) so with a bit more greasing of the other moving parts I think I can get the total resistance down enough for it to be more reliable.

Thanks again for the electronic diagrams Marc, they were very useful for fault finding even if they still didn't quite explain the mystery of no comms when swapping modules