X7 electric tailgate

[GiveMeABreak]

Well I'm just wondering if the lock or the striker is the problem as in the note that follows the closing conditions would indicate that is stops 15 ° before total closure.

Conditions: Closing
The motorised tailgate ECU commands the closing of the tailgate if the following conditions are met :

• A closing request has been sent by the user
• The vehicle is unlocked
• The motorised tailgate is unlocked
• Vehicle speed is less than 5 km/h
• The vehicle is not in economy mode
• The engine is not in the starting phase
• The ignition key is not in the starting phase

N.B. : If the motorised tailgate lock is closed, the motorised tailgate ECU commands the closing of the motorised tailgate, but the closing is stopped around 15 ° before total closure.

This is the control logic sequence:
When there is a motorised closing, the motorised tailgate ECU commands in this sequence :

• The coming out of the motorised striker (if the tailgate is in the maximum open position, the striker is commanded at the same time as the tailgate)
• The closing of the motorised tailgate
• The going in of the motorised striker (once the lock has latched on the striker)
• The declutching of the mechanism

Another possibility:
Fault: Motorised striker plate (Striker jammed in)
The motorised tailgate remains operational, but complete closing is not guaranteed in certain cases (windows/doors closed); The tailgate will come back up by 15/20° and emit a sound alert (2 beeps)

Fault: Lighting output of the motorised tailgate closing switch
- AD69 = Short circuit to positive
- BD69 = Short circuit to earth or open circuit

[furriegurrie]

Not familiar with this as such on this type of C5 but the older types suffer from breaking wires in the connection between the car and the tailgate

[GiveMeABreak]

Not relevant to this model - that's a completely different issue as this is a motorised tailgate issue that the older models did not have.

[furriegurrie]

I know that, but as TS mentions the switch isn't lit and the fuse seems to be fine I was just suggesting a possible cause. Citroens are not known for their reliable electrical connections or cabling. A break in the wiring seems a possibility....

[GiveMeABreak]

It’s obviously electrical, whether ECU related or wiring, but these have a separate tailgate ECU and a multitude of connections to factor in with the BSI. There are stacks of faults, but none of these seem to be reported.

The fact that the tailgate is working means the motorised tailgate operation is working fine, but the issue may appear to be with the striker and lock mechanism which reaches out to some degree and grabs the lock, which pulls it down and locks it. That part may be the issue.

[Trainman]

Right, I've been playing this morning, and I'm more confused than ever.... I've done the tests some work, some don't

Control of buzzer: worked fine each time I tested it.

Control clutch motor: again worked fine.

Control motorised tailgate: FAILED tailgate didn't open.

Control Lighting of the motorised tailgate switch: Now this get's interesting....... as the tailgate open the switch is illuminated, as the tailgate raises to about 30% open the switch goes dull and the tailgate stops moving and won't close, however, if you stop the tailgate moving whilst the switch is lit, the the tailgate works normally.

Control of striker plate: I haven't tried this yet given that the tailgate opens some of the way, I think this is working fine.

Now what's throwing me a curveball, is that as soon as the tailgate stops moving, it loses communication with diagbox. There are still no fault codes being logged.

[GiveMeABreak]

I'm a little confused by what you've said above:

. as the tailgate open the switch is illuminated, as the tailgate raises to about 30% open the switch goes dull and the tailgate stops moving and won't close

The tailgate when opening will only open to the user-programmed opening angle - so I wouldn't be surprised if it stops at 30 ° if that is what has been programmed. You can of course reset it to the default where it opens fully.

But if you are saying once opened to the programmed angle, it won't then close on command of the close button?

[Trainman]

If I open the tailgate, it opens to about 30% only, looking at the red button this is illuminated. Now once the tailgate gets to about 30% open, the tailgate stops opening and the light in the switch goes out.

Once the light goes out the switch stops working, the tailgate stops moving and communications with Diagbox.

[GiveMeABreak]

Ok, so I would suggest clearing any user-defined opening settings - hold down the switch inside the tailgate for 3 seconds to clear any settings. If cleared it should result in the tailgate opening to the default height of all the way. If it's still not working - it's going to be a mare to troubleshoot without a fault code.

[Trainman]

Marc,

I’ll give that a bash shortly

[Trainman]

Nothing, still doing the same

[GiveMeABreak]

Here's some info in case it helps if some investigation is required:

(1) Motorised tailgate balancing struts.
(2) Motorised tailgate mechanism.

• The motorised tailgate mechanism performs the opening and closing of the motorised tailgate.
• The position and the speed of the assembly are measured by a linear potentiometer incorporated in the motorised tailgate mechanism.

Function

• The motor of the motorised tailgate mechanism "a" drives the gears "e" in rotation, depending of the direction of opening or closing of the motorised tailgate.
• The rotation of the gears "e" drives the movement of the chain "f".
• The fixings "g" of the motorised tailgate balancing strut cables are linked to the chain "f", driving the movement of the motorised tailgate balancing struts, making the tailgate open or close.
• The linear potentiometer "h" gives the position and the speed of the tailgate to the motorised tailgate ECU.
• The motorised tailgate mechanism can be clutched via the clutch "c" by action of the clutch motor "b" on the clutch spring "d", which locks or releases the central shaft of an epicycloïdal axle located under "d".

(1) Anti-pinch sensors. (2) Motorised tailgate balancing strut. (3) Motorised tailgate mechanism. (4) Motorised tailgate opening control. (5) Motorised tailgate closing switch. (6) Motorised tailgate ECU. (7) Motorised striker plate. (8) Motorised tailgate lock.

Specification of the linear potentiometer:

• Voltage 5 V
• Information outputs: Position between 0,4 and 4,6 V (0,4 V = With the tailgate closed ; 4,6 V = With the tailgate open)
• Total resistance: 5 kohms
• Resistance between the information output and the earth of the potentiometer: between 30 Ohms and 4,9 kOhms approximately (Measure : connector disconnected

Specification of the clutch motor:

• Control: OCR
• Duration of voltage: Around 500 ms

Operation voltage thresholds:

• Less than 8 V - more than 16 V: The system is not operational, declutching is not possible
• Between 8 and 10,5 v: The system is not operational, only declutching is possible

Channel No. & Designation 8-Way Black Connector

1 - Motorised tailgate motor control (Tailgate opening direction if at +)

2 - Motorised tailgate motor control (Tailgate closing direction if at +)

3 - Not connected

4 - Tailgate mechanism clutch motor control (Declutch control if at +)

5 - Potentiometer supply

6 - Tailgate mechanism clutch motor control (Clutch control if at +)

7 - Motorised tailgate position information

8 - Potentiometer earth

Here are the ECU connections - obviously part 'b' is the male connector of the female shown above in more detail.

Channel No & Designation Tailgate Locking 16 Pin Connector 'a'

1 - Electrical earth

2 - Lock information tailgate open

3 - Positive control : LH anti-pinch sensor

4 - Positive control : RH anti-pinch sensor

5 - Negative control : RH anti-pinch sensor

6 - Motorised striker plate control

7 - Boot closing switch lighting control

8 - Motorised tailgate opening control status

9 - Power earth

10 - Motorised striker information: gone in

11 - BODY CAN low

12 - BODY CAN high

13 - Control - LH anti-pinch sensor

14 - Tailgate opening exterior control signal

15 - ECU supply

16 - Power supply

[Trainman]

I’ll strip the tailgate down on Sunday and do some checking, one thing I did wonder was if there was a tilt switch somewhere in the tailgate?

In the mean time, those diagrams give me things to check

[GiveMeABreak]

Ok, good luck with it Steve - I've added the ECU wiring connectors too showing the 16 pin connector too for completeness.

[Trainman]

I have the feeling it’s going to be a long day, but I’ll let you know. It has to be some sort of power supply issue, for the button to stop working.