C5 X7 2010 - 3.0 HDI - BHI not cummunicating

[LLO]

Hello everyone!
I need some help from this awesome community!

I’m having a problem with my Citroën C5 X7 with the 3.0 HDi engine. It all started when my rear strut began leaking heavily. All the fluid leaked out, and the car limped home on the lowest suspension setting.
I bought a new strut and sphere and replaced both parts without any issues.

Then the real problems started. When I started the car and tried to bleed the hydraulic circuit, nothing happened. The main power fuse for the BHI was blown, so I replaced the fuse, cleaned the whole hydraulic motor, and reassembled everything.

When I started the car again, I could hear the motor whining — awesome, I thought the problem was fixed! Unfortunately, the car still sits completely on the ground.
I connected Diagbox, and things got more interesting. I can connect to all systems except the hydraulic unit. I get a “Communication error” for the Electronically Managed Suspension.

So, I decided to buy a used but functional BHI unit from another 2.0 HDi (expecting to reprogram it to communicate with the Damping ECU).

However, the replacement unit also doesn’t communicate with the BSI. The BHI motor is silent. I believe this is because it’s not configured properly — the seller promised it was working fine before removal.
I then took out my multimeter and checked the wiring at the BHI unit.

• Voltage on the motor is correct.
  The ECU 32-pin connector has the correct voltage.
  Grounding is solid (I cleaned and measured the grounding points).
  Resistance between CAN H and CAN L is about 60 Ω (which should be fine).
  Both CAN lines show 2.5 V.
  The relay near the unit is working properly.

Now I’ve hit a dead end — I’m out of ideas on what could be causing the issue.

Some Diagbox screenshots are attached.

Thanks for any advice!

EDIT: Forgot the screens.

[Kees]

The things you did wrong is, if the motor is without LDS you have to apply 0.5 bar after you fill the tank.
This is why the fuse is blown because the motor comes overhead.
Next fault, think that the BHI is broken and change with an other one.
So put back the original pieces and follow the right procedure!!

[mickthemaverick]

That is an extensive fault list. I cannot help wondering if there is a proportion of historic problems among them which may be confusing the current position. I'd suggest you clear all the faults and then run a global scan to be sure that you are only looking at current problems.

[Kees]

There's also an other thing, sinds you have a separate CSS computer for the suspension There's a complete different BHI on it!!
If the unit you buy is not from a 3.0 HdI it will never work!!

[Kees]

@mickthemaverick:
Look at my post, he made big mistakes!!
All this readings has nothing to do with the problem.
He put an pomp from a 2.0 hdi on the car!!

[mickthemaverick]

@mickthemaverick:
Look at my post, he made big mistakes!!
All this readings has nothing to do with the problem.

That is what I was trying to tell him, assuming he would follow your advice first.

[Kees]

@mickthemaverick:
This is what you get with a complex system, and not studying how things work.

[Kees]

@LLO:
A question, how is the situation with the problem of the car?
Did you solved it?
You ask for help on the forum and get replied but gif no response anymore.
Greetings,
Kees.

[Paul-R]

LLO last visited the forum on October 28th so he should have seen all the replies. We can only wait for his reply. Perhaps it's taking a long time to work his way through everything!

[LLO]

Hello guys, thank you so much with your ideas. It really took me some time to modify the cap for the LDS reservoir. So I could apply some pressure on the fluid.

Well it really worked on first try. Hydraulic motor was able to catch fluid and car is going up and down like before.
I tried to apply some pressure before also but only with my mouth which was probably not sufficient. I need to train my lungs more.

Anyway next step is to clear all the faults and check what errors persisted. I think a lot of errors might be caused by my shenanigans with wiring, fuses etc.

For my own peace of mind. Could you explain to me why the BHI ecu is not cominicating with Diagbox? I would like to check the status, because I think that a ride is a bit harsh on my opinion (it was already before) and would like restore it's smoothness.

[Kees]

Hai, glad, you have progressed and solved the main problem.
Dit you replaced the original pomp/Bhi? This is important because the difference in the suspension system, between the 3.0 and 2.0.
About the behavior of the suspension, it's better if the center spheres in front and back are good to place a resistor 10Ohm/10W in the connector from the stiffness regulator, so instead of the regulator the system see the resistor and you get no errors.

[cit-rotti]

For my own peace of mind. Could you explain to me why the BHI ecu is not cominicating with Diagbox? I would like to check the status, because I think that a ride is a bit harsh on my opinion (it was already before) and would like restore it's smoothness.

This is most likely due to your Chinese clone. This problem occurs frequently with the C5.