Citroen c5 x7 no communication with Css

[Bils]

I have a problem with my 2009 2.7 v6 hdi c5. The front of the car sits very high and is super stiff in normal mode. Diagbox gets communication error trying to connect to the css/variable suspension ecu. So I can’t program the heights. I’ve checked all fuses and swapped the ecu once. I’ve also measured the wires between the css to the bhi.

Anyone have any ideas ?

[mickthemaverick]

Have you carried out a BSI reset as per the directions in the link below? If not it may be worth doing that and then seeing if it will communicate.
viewtopic.php?p=601679#p601679

[Kees]

What happened to the car, that this problem with the suspension occurred?
Was there any maintenance done?

[Bils]

I’ve tried bsi reset today nothing happened, I bought the car as is, so I don’t know how it happened.

[Kees]

The problem with the v6 could be that one of the front height sensor is faulty, or the bracket on the lower arm is bent.
When one is out of range the system see this as an anomaly.
About the communication error, sometimes is it the (chinees) diagbox itself.

[Bils]

I’ve change both of the front height sensors that got rid of the code c1141 from the suspension ecotech. I’m using fantomel diagbox, so you think that could be the issue ?. It connects to all the other “ecus”

[Kees]

You said nothing about the rear of the car, so i asume this part is oke, the suspension works good and the height is around 73 cm.
This means that the CSS and BHI works properly.
About the sensors are you sure you put the right one's,
Yellow right front and red left front.

[Bils]

Yea the rear works perfectly, yes I checked with part numbers and the colors match yellow and red. Low and high mode works as well it’s just normal mode in the front that is misbehaving

[Kees]

Have you noticed that some parts are replaced/new, for example the front lower arms, or the brackets from the front sensors?

[Bils]

I haven’t noticed anything particular but I will double check tomorrow

[Kees]

Good, I will make some fotos about the connection rod between the sensor and the bracket, maybe they are in the wrong position.

[Bils]

They don’t look damaged and nothing looks replaced as far as I can tell. If I disconnect the “dogbones” I can adjust the height but the suspension is still hard as a rock.

[Kees]

Oke, that's a good sign. But wat i see is that the bracket on the left side is bent, if I look at the shadow on the lower arm.
In the past I changed both lower arms, with the brackets mounted, but these where not original, when I finished the job, the car stand around 2.5 cm higher at the front and it was not possible to correct it with the diagbox, because it was not possible to complete the procedure.
The reason was that the brackets are the same, but the original are different between the hight (foto).

When I correct this there was no problem anymore to correct the height of the car.
What i mean and said before, if there is an anomaly between the data of the twoo censors, this can be the reason why the car is to high.

About the stiffness, if you lower the car with the switch inside, and the suspension is still hard, then I should check the pressure of the spheres.

[Bils]

You are correct the bracket was bent, and adjusted the bracket and the height went down to about 72cm from the ground to the wheel arch and the suspension got soft. But there is still a communication error from the css. I will test drive it and see how it feels. Are new brackets available?

[Kees]

The correct height should be 73 cm, but a little lower is not a problem, it even makes the suspension softer.
About communication, I should try, with an other diagbox and vci, because now it seems that the system works properly, it means that all communication between the computers (can high/low) are oke.