C5 X7 Hydractive suspension too bouncy (wobbly)

[barungla]

Hi all...
First of all let me thank all members of this forum for all useful stuff I have learned on FCF during past several years of reading your posts.

But now I am dealing with an inconvenience that I just can't wrap my head around. And that is why I decided to write this post. Maybe some of you will have any ideas and will be able to provide some helpful advice.

My C5 X7 2.0HDi 2009 (VIN: VF7**************[VIN obfuscated, can be read by forum staff]...) drives very wobbly. Especially if I drive on a bump on one side only (roll movement of the car). Problem is a bit better when driving on a bump with both wheels on axle simultaneously (pitch movement of the car) - something like a speed bump. The car is feeling like the struts are compressing OK, but the suspension is not able to dampen out the bounce.
The car (suspension) also makes very loud noise when struts have to extend rapidly. For example when I drove into sudden road height change (into missing strip of asphalt) even is this height change is small - let's say as small as cca 30mm. The only way to avoid this loud noise is to drive over such thing really slowly, less than 15kph. The same thing happens when driving over a speed bump. I'd say I have to drive below a 50% of speed limit over these things.

If you guys have any ideas or advice on what could be wrong and is worth checking out it would be much appreciated.

Best regards,
Barungla

[dulenator]

I drove four previous model C5s before I bought one, and all of them had the same issue when going over speed bumps or something similar.
When I finally bought one, I checked everything and didn't find any issues with the suspension. The ride was excellent on all of them, and it is great on the one I own, but that thing is a little bit annoying.
It sounds and feels like you've hit the ground without suspension.

Someone knows more about this than us and will let us know why this is happening.
These are old cars, and all those I drove had original spheres on them. So maybe that is the problem, but I would not buy new ones to find out it did not resolve the issue.

[aerodynamica]

Hi there, I'm not sure exactly but I have all 7 spheres renewed and I find that the front suspension sometimes has a real 'bang' like it tops out. Only on something like speed bumps or similar. If I go over longer speed bumps it only bangs if I go fast. I never find any problem driving on the motorway etc. It reminds me of older hydraulic Citroens where the suspension is out of adjustment and riding too high overall. My C5 however looks exactly at the right height. I wonder if it is a characteristic fault.

The only thing I find a bit strange on my C5 is the strangely underdamped motion at the rear sometimes on the motorway. It was like this with the old spheres and continued after the spheres were renewed, new LDS and the full system bled several times. I think it is actually supposed to be like that (?)

I did find that the front suspension improved a lot with the new spheres, The rear changed a bit but not sensationally.

[barungla]

It sounds and feels like you've hit the ground without suspension.

Exactly like that

My C5 however looks exactly at the right height. I wonder if it is a characteristic fault.

The only thing I find a bit strange on my C5 is the strangely underdamped motion at the rear sometimes on the motorway. It was like this with the old spheres and continued after the spheres were renewed, new LDS and the full system bled several times. I think it is actually supposed to be like that (?)

That is also 100% correct in my case.



The odd thing is, that I own the car for four years now. And it seems that, the suspension is more wobbly as it was when I bought it
I also own a 2002 C5 but it rides (at least in my opinion) much better. In regard to suspension of course. If anything the C5 X4 suspension is becoming more hard (I believe that this is normal) because of old age.

Today I also noticed that my C5 X7 suspension height can only be set to lowest and 'normal' position. If I try to set it to 'high' the pump is working and rear is lifted for about 40mm but at the front only for about 20mm. The car also does not report reaching 'high' position and the pump runs nonstop. After about 3 minutes I decided that it is better to press 'down' button and abort the lifting.
As said earlier, to me, the car seems to be at the proper ride height at front and at the back.
If anything it is maybe a bit high at the front - about 450mm from wheel center to wheel arch in normal position.
At the back it's about 400mm from wheel center to wheel arch in normal position.

I read in several other threads where the common measured distance is 41,5cm in front and 38cm in rear.
Compared to that my car is riding to high.

Could that be the source of 'strange' suspension behavior?

[Jay-Bruce]

I've been holding off chiming into this thread, waiting for a real expert to comment, If your car cannot get to high and highest settings, I'm going to suggest checking the fluid level, lower car to lowest setting, open the LDS tank, make sure fluid level is between the steps on the squirrel cage inside the filler neck.

The bouncing sideways sounds like what our X7 does when our faulty rear firmness regulator dumps the back end. The way I mitigate it is that when it starts going wobbly, I pull over, raise the car to high, not highest setting, then lower it to normal height, do that and you should feel an instant improvement.

You can either use the following information as instructions on what to do yourself, or to prime your chosen mechanic on what they need to do to your car:

This excellent post by Marc "GiveMeABreak" shows how to properly check the fluid level:

The fluid levels should be checked with suspension depressurised (ideally), but as James says, put it on the lowest suspension level and wait for it to fully lower. The following diagram shows the levels for a C5 X7 - the BLUE being the maximum fill level and he ORANGE the minimum level.

There is a fantastic post with a procedure written by Phil C. and posted on the C6 Owners forum under username on there, CruiserPhil, it shows how to refurb the rear firmness regulator, link: http://c6owners.org/plugins/forum/forum ... hp?2638.36

[Jay-Bruce]

Codswallop! I forgot to add a couple of things...

You'll need a good fault code reader, like a delphi one (clones are available from eBay), or a Peugeot lexia, which the forum has an arrangement with a diagnostics tool business for well priced kits. Details on the discount scheme for he Lexia deal can be found here: viewtopic.php?f=51&t=60112 If you check the fault codes for the Valeo suspension ECU, you might see something like "U1116 - Suspension ECU - invalid data - intermittent" this sort of thing could indicate that your rear firmness regulator is dumping the rear end, leaving the sensed ride height as being lower than the ECU expects to see, given the line up of valves in the BHI. It could also indicate that some of your height sensors are going bad.

Installing and setting up new height sensors is a bit of a faff, and needs to be done pretty much exactly in accordance with the official procedure, which is available through the resources section of the forum. The process is also different if you have a 4-cylinder engine compared to a v6 engine as the v6 models, both petrol and diesel, have an extra height sensor compared to the i4 models. Both i4 and v6 procedures are available in the resource section.

[MattBLancs]

No pearls of wisdom from me, only to say my C5 X7 also "thumps" from the front, on the rebound from a speed bump at relatively low speed. The only thing I would add is it is mostly just a noise - no strong sensation can be felt in the car in this situation. Don't like it though, doesn't sound nice / right!

[aerodynamica]

My C5 however looks exactly at the right height. I wonder if it is a characteristic fault.

The only thing I find a bit strange on my C5 is the strangely underdamped motion at the rear sometimes on the motorway. It was like this with the old spheres and continued after the spheres were renewed, new LDS and the full system bled several times. I think it is actually supposed to be like that (?)

That is also 100% correct in my case.


Today I also noticed that my C5 X7 suspension height can only be set to lowest and 'normal' position. If I try to set it to 'high' the pump is working and rear is lifted for about 40mm but at the front only for about 20mm. The car also does not report reaching 'high' position and the pump runs nonstop. After about 3 minutes I decided that it is better to press 'down' button and abort the lifting.
As said earlier, to me, the car seems to be at the proper ride height at front and at the back.
If anything it is maybe a bit high at the front - about 450mm from wheel center to wheel arch in normal position.
At the back it's about 400mm from wheel center to wheel arch in normal position.

I read in several other threads where the common measured distance is 41,5cm in front and 38cm in rear.
Compared to that my car is riding to high.

Could that be the source of 'strange' suspension behavior?

Y'know, mine also has a problem with the height adjustment. Normal height seems/ looks fine but raising it up one level sees the rear raise up by an amount but the front goes and continues right up to highest and when it reaches there the pump continues to run. If I then set it to highest suspension the rear raises further to highest and the front stays fully up with the pump constantly running (until it times out).

No message appears to confirm it reached either high or intermediate height.

I was changing the transmission fluid today and had the Lexia connected to observe the fluid temperature reaching 60 degrees C. After the longwinded fluid change I had a look at the suspension diagnostic and looked at the readings for the ECU.

Data for the suspension heights.

This is the data for the suspension at normal height. As far as I can tell the 2 lines 'Front setting height/ Rear setting height' are the number of steps of each height sensor data for the set position of the 'Normal' position. I know this because these values change to two higher numbers when you press the up button once to raise to the intermediate position and their values increase further when you press up again to raise to maximum height.

The 2 lines 'Front Filtered height/ Rear filtered height' appear to be the actual data from the front and rear sensors. Pushing the suspension down makes them change live and you can see they have a value that's close to the 'setting heights'. Presumably there's a type of fuzzy logic or range that is acceptable to be 'close enough' to the set heights likely because the data will be always changing with the vehicle in motion.

What I found when raising the height to intermediate and high positions is that the steps data from the front height sensor stops at 154 step where the 'High' setting wants it to raise to 170 step. The rear continues up to the demanded step of 152 and appears to function normally. Why does the front data not go beyond 154? This is obviously the reason why it never stops the pump - it doesn't think it ever reaches the 170step value at the front..

Here's the picture of the data at 'High' position:

It is like the data runs out after the front suspension raises by an amount and the ecu keeps trying to raise the front above 154 step to get to 170 but never does.

[aerodynamica]

Anyway, I don't know what's wrong with mine (it's a brand new front sensor) but might be related issue?

I did discover something that answers my question from another thread. I wondered why the front suspension drops down a bit when the ignition is turned off. Well, I turned it off with the diagnostic hooked up and as soon as the ignition is turned off - indicated on the diagnostic as: "ignition positive - absent" - you see that the 'setting height' for the front changes from a normal height of 128 steps to 120. So the drop down is designed in. I assume then that Citroen decided to give the car a bit of 'stance' for when it's parked....

[aerodynamica]

Indeed, I just looked at the other pictures I took of the data and notice that when it is set to 'LOW' height the front sensor goes to a value much lower than the 'setting' step for the low demand.

Low selection calls for the front step data to be 92 but when the front drops down to low position it goes further than that right down to 85 step. It almost seems like my front setting is out of phase

I wonder if the physical rod attached to the front anti roll bar was disturbed in some way causing the sensor to be moved too far one way and not far enough in the other? This problem on my car began after I got it back from the so-called Citroen specialist who fitted the replacement steering rack. I just don't know though..

Codswallop! I forgot to add a couple of things...

You'll need a good fault code reader, like a delphi one (clones are available from eBay), or a Peugeot lexia, which the forum has an arrangement with a diagnostics tool business for well priced kits. Details on the discount scheme for he Lexia deal can be found here: viewtopic.php?f=51&t=60112 If you check the fault codes for the Valeo suspension ECU, you might see something like "U1116 - Suspension ECU - invalid data - intermittent" this sort of thing could indicate that your rear firmness regulator is dumping the rear end, leaving the sensed ride height as being lower than the ECU expects to see, given the line up of valves in the BHI. It could also indicate that some of your height sensors are going bad.

Installing and setting up new height sensors is a bit of a faff, and needs to be done pretty much exactly in accordance with the official procedure, which is available through the resources section of the forum. The process is also different if you have a 4-cylinder engine compared to a v6 engine as the v6 models, both petrol and diesel, have an extra height sensor compared to the i4 models. Both i4 and v6 procedures are available in the resource section.

have you got a link to the height set up? I'd be keen to have a look at the full procedure (EDIT/ think I found it)

[KennyW]

Graeme,

I had the same thoughts as you, it put it down to wear and tear at the dog bones. The metal ball on the anti roll bar connector corrodes and the diameter is less thus play in between the 2.

My reasons I moved the dog bone about last week to make sure it was not seized and the height moved. Move the suspension to high and back to normal and the ride height returned to normal.

I have been tempted to replaced them but at over £200 a corrector decided against it.

Kenny

[aerodynamica]

Hiya Kenny, I got a new front sensor for around £30, it was from the place in Derby that does the hydraulic pipes. I believe the part is also used on other PSA cars as a headlamp level sensor.

But yea, I might have a look at the front dogbone again perhaps when I do the inner front control arm bushes in the coming month.

[KennyW]

The sensors are not dear but the connector on the anti roll bar are a ridiculous price. I've not checked recently

The sensor is relatively easy to change but access is tight. Fortunately, when I did mine the rack was off the car as it fits on a bracket on the rack.

Kenny

[Jay-Bruce]

Isn't there some tom fluffery about different coloured sensors for different locations on the car?

[aerodynamica]

Not certain about that Jay, I fitted a new front one that was identical to the original. It has an opaque/ white colour. I only changed it because I suspected the original one had a worn track and was giving bad readings and this was the cause of the problem moving to intermediate height etc but the new one made no difference at all. I did grease up the dog bone connector and could feel that it was not seized but all in all made no change.

The self leveling action when the car is at normal running height is very good - I dropped off my friend this morning and when he stepped out the suspension floated up a bit and it wasted no time in lowering back to the correct height.