C5 X7 - B1131 - RH Headlamp Communication fault

[wurlycorner]

Hi all

Still on the discovery process with the new X7 addition, there's a fault with the right hand headlight.
Symptoms is that I noticed that the 'level' of the headlight is 'hunting' up and down continually.
Did a diagnosis with my Thinkcar (didn't have the time or inclination to dig out diagbox etc.) and it's stored B1131 "RH Headlamp Communication" in the Directional Headlamps module.
There's nothing logged in the BSI.

As far as I can see, everything seems to function correctly on that headlamp - it just has the 'hunting' problem on the height.
I did a quick pin-out check to compare left/right headlamps and both match. For reference what I have with headlamps on dipped is as follows:

• Pin 1 - 3mV
  Pin 2 - <no pin>
  Pin 3 - 12.8V
  Pin 4 - 12.9V
  Pin 5 - 11V
  Pin 6 <no pin>
  Pin 7 - 3mV
  Pin 8 - 3mV
  Pin 9 - 12.7V
  Pin 10 - Canbus communication
  Pin 11 - <no pin>
  Pin 12 - <no pin>
  Pin 13 - 1mV
  Pin 14 - 5mV
  Pin 15 - 6mV
  Pin 16 - <no pin>

Looking at the network comms on Pin 10, both sides (left and right) also look identical and it's a 'healthy' data packet signal.
As that is the only pin carrying data though, there's only 'CAN high' data , not a corresponding 'CAN low' (I assume that's how it's meant to be as there is no DTC for the left hand headlamp and that was identical - though it surprises me a little).

Anyway, that's about as far as I can go, without more info - DTC code set criteria and wiring diagram etc.
Does anyone have those - or any personal experience with this fault - by any chance please?
I have done a search on the forum and google etc. but nothing useful has come up.

nb: I'll see if I can upload a video I took of the CAN signal I saw and add it in the thread, if people are interested.

Thanks

[wurlycorner]

Link to view video of the data activity:

(Clip shows connectors unplugged/front-probed for convenience, but activity looked exactly the same when plugged in/back-probed)
nb: youtube seems to have messed up the video quality unfortunately. Was filmed in HD so the data activity (green and red traces) were clear on the device but that isn't so clear after upload to youtube

[GiveMeABreak]

There's nothing to go on for this fault as it's a Non Characterised' Fault:
B1131: Right-hand headlamp communication.

Diagram for Xenons

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Wiring for Xenons

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With the exception of the wiring codes, most of the component codes are indexed here:

PSA Electrical Diagrams - Wiring & Symbols Codes Index

[wurlycorner]

Thank you Marc - shall investigate further and see what I can find...
On initial glance, does indeed look to corroborate that there is only a single data connection to each headlight (not High/Low pair), so that's good that nothing has gone 'AWOL' as short to ground etc. in that regard.

[wurlycorner]

Couple of components not listed in the component codes list.
If you get a moment to look them up please Marc, would be appreciated:

0004 (I'm guessing this is the indicator lights on the instrument binnacle?)
7130
5008 (I'm guessing this is the rain/sunlight sensor?)
6606 (I'm guessing this is the headlight height and direction control unit - 6605 is listed as headlight height control unit)
78-- (I'm guessing this is a reference to 'continued on the ESP wiring diagram'?)
77-- (I'm guessing this is a reference to 'continued on the suspension wiring diagram'?)

Thanks

[GiveMeABreak]

Here you go:

Yes, the dotted areas link to the specific diagrams for those systems.

The suspension system on these vehicles is unique in that it is tried into many other systems to provide the handling dynamics according to factors like the vehicle speed, the angle of the steering wheel and force exerted on it by the driver, the ESP data from various sensors, body movements (pitching, rolling), cornering, acceleration, braking etc.

The V6 models have a separate suspension ECU as well as the one in the BHI. On these specific models, the functions are separated for each:

The Role of the variable damping suspension ECU (CSS):

• Acquisition of the information from the 4 body height sensors
• Management of the steering assistance
• Dialogue on the IS CAN

Role of the integrated hydro-electronic block ECU controls the following components:

• The electropump unit and its electrovalves
• The stiffness regulator electrovalves
• The vehicle ride height (handled by the CSS computer on some 2.2 and V6 models).
• The stiffness

Back to the components:

0004: instrument panel /
7130: multiplexed steering angle sensor
5008: rain/sunlight/tunnel sensor
6606: dynamic headlamp beam correction unit

[wurlycorner]

Legend. Thank you!

[wurlycorner]

Just to update on this, I spent a bit more time on it last week, with Diagbox this time.
I function tested everything on both headlights (so I could be sure the RH was behaving correctly against a 'known good').

Everything functioned correctly on the RH headlight, with the except of the left/right swivel, which did not respond.

So to me, that further confirms there absolutely IS communication with the headlight (so it's not a 'loss of, or 'bad' communication') and either the L-R motor is defective, or the ECU in the headlight is partially defective, or perhaps there is a defect on the cabling to the motor, internally within the headlight.
Seems like the headlight is going to have to come out to check over, which I'm not hugely looking forward to...

Does anyone have a copy of the official instructions to remove the bumper?
I've done a search on the forum and stickfinger posted information with pics here, but I'd like to see the official instructions too if possible please - and I can't seem to find those posted anywhere?

[GiveMeABreak]

In my post here:

C5 X7 Front Bumper Removal

[wurlycorner]

Oh brilliant, thanks Marc - not sure why that didn't come up when I searched!

Trust Citroen to require a special tool to remove the bumper (backwards step from the earlier C5).

Do you know the part number for the clips that must be replaced, please?

Thanks

[GiveMeABreak]

(81) Bumper Fixing Clips, part: 743712, £4.13 (should be a for a pack of 4), but don't quote me on that!

[wurlycorner]

Thanks Marc