Citroen C5 Mk II Suspension Will not rise

[howardaskew]

The car arrived with the front down and the rear normal.

It would not move using the buttons. The owner was told to buy a new "Pump" by a Sussex based garage that previously said the same car needed a new "turbocharger".
The previous turbocharger fault was cleared by changing the oil.

The history of this suspension fault was that the car had a new tyre fitted and also suffered a flat battery when the lights were left on.
The battery has since been replaced.

I tried to clear faults by disconnecting and reconnecting the battery following procedures mentioned elsewhere on this forum.

I bought a copy of Lexia 3 7.76. It works on this car and on my own C5 Mk 1.

I found the fault log full. 60 in total. I read them and cleared them. Many of the faults were low voltage at various ECUs that made sense from the flat battery issue.

The radio and multifunction display have faults that return. The injectors have faults that return. I consider that these faults are of a minor nature.

The suspension had faults.

Permanent Fault - Body Height Sensor Front
Permanent fault - Body Height Sensor Rear
Temporary Fault - Steering Wheel angle sensor no value received
Remote fault - Temporary fault - No communication with built in systems interface.

I did notice faults
D305 No communication with the steering wheel angle sensor.
D105 Steering Wheel rotational speed information no signal.

These were all cleared.

Using the Actuator Test functions of the Lexia.

The Pump runs for a short period but the vehicle does not rise.

Now when I push the rise up button by the gear stick the pump runs for just under 5 seconds but does not rise.

I would appreciate some input from my fellow forum members to try and diagnose the actual fault.
I am not experienced with the Lexia but have good computer and mechanical knowledge and I am an Electrical Controls and automation engineer by profession (non automotive).

The car is right on the bump stops so will not drive.

[wurlycorner]

I would start with the height sensors.

If it has a permanent fault from them, it has no idea where the car is at (height-wise) so it would not do anything to alter the suspension height.
I would say that you need to get under the car, visually inspect the sensors (do they look ok?) check the electrical connections are good, check the mechanical link to the ARB's is there and bolted up tight... And if that's all good, then disconnect the sensors and manually test them or just swap them with one from a breaker (should be available very cheap).

This fault

Temporary Fault - Steering Wheel angle sensor no value received

in my experience (somewhat limited, but have plugged in to 4 C5's in the last 3 months and all of them had this fault ) I would definitely ignore for now. It has no bearing on lifting the car to correct ride height.

[howardaskew]

Wurlycorner,

Thank you for your prompt reply.

Is it likely that both height sensors would fail? The permanent fault on the log was cleared and did not return.

The pump only runs for a very short duration without moving the car. 3 - 5 seconds max. Could a dump valve be stuck open?

Using the Lexia you can command the car to rise. This works on my car. On this car it does not rise.

I may try to pressurise the system to try and bleed it.

Does anyone know how the sensors give an analogue value to the ECU? Is it a potentiometer (variable resistance?)

I may be able to try and fool the ECU.

Howard

[myglaren]

the sensors are potentiometers and do fail but it is rather suspect that both appear to have failed.
I wonder if the input from the height correctors into the pump ECU is at fault.

Have you checked that there is LDS in the reservoir?

[wurlycorner]

Yeah I agree, sounds unusual for them both to have failed, but you never know... (car been through a deep flood???) And if it logged it as a hard fault, then it's well worth starting there? If they check out ok, then you've knocked something off the list.

[howardaskew]

Just an update to this fault.
Pump is now dismantled and the cover over the brushes reveal a lot of carbon.

Should I try to replace the carbon brushes?

Here are the photos.

https://dl.dropboxusercontent.com/u/145 ... G_0226.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0227.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0228.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0229.JPG

This type of motor does not justify the £1000 Citroen price tag.

I have a Lexia and a one man bleed kit that connects to the reservoir cap and goes to a reservoir about the size of a drink can that is pressurised by connecting with the purpose made pipe and fitting to the front tyre.

I will post photos and an update to my success or not.

Howard

[howardaskew]

Update.

All back together ok. Refilled 3.5 litres.
I noticed a date in 2010 on the pump that indicates it was replaced then.

Pressurised system with eazibleed.

However Beast does not rise. I can hear pump operate for a short duration.

Lexia is showing no faults.

Now I need to know how to use Lexia properly.

I will keep posting my lack of progress.

[dnsey]

That doesn't look right at all - are you sure that it's carbon? Residue from worn brushes is usually a fine dust, not the sort of granules your pictures show. I wonder if there's something else worn on the pump.

[white exec]

Your first post said that the rear of the car was normal. If that means it is rising and falling normally, then presumably the pump, even though dirty, is working. Does the back rise to normal height from lowest?
Is the fluid level really correct?
Any bubbling/frothing in the reservoir, while engine running?
If you jack up the car to get its weight off the front wheels, can you get any hydraulic movement of the wheels?

[Gibbo2286]

That doesn't look right at all - are you sure that it's carbon? Residue from worn brushes is usually a fine dust, not the sort of granules your pictures show. I wonder if there's something else worn on the pump.

There's a small breather hole in the bottom of the motor, water ingress through there and the carbon dust make a pretty messy sludge, I've seen also one that had let oil through from the pump into the motor causing an even worse mess.
It's possible also that the brushes have been arcing and there is burned material from the brushes and commutator.

[howardaskew]

Hi,

Thanks for the replies. I used a clean paintbrush to remove the carbon. It was a pretty fine dust although it may have had some contaminants. It certainly was not a sludge.
The commutator looked undamaged.

The Pump runs but not for very long. Even using the Lexia.

I notice that the level in the reservoir has not gone down very much. I am tempted to try and bleed.

My view was that changing the pump de-pressurised the system and any air ingress would only occur in the small bore pipework either side of the pump.

When the pump runs the interior light dims slightly and I can feel the vibration.

I bought a Pump from Ebay which was supposed to be from a MK2 but it is fitted with a second rubber hose connection like my MK 1. The seller was insistent that I should try the pump but never answered my question what I should do with the second rubber pipe. So we have agreed to return it.

My next plan is to put a permanent signal to the pump and see if I can force the car to rise. In for a penny in for a pound. I want my drive back!

The pump is not showing faults on the Lexia apart from a temporary one for the steering angle sensor although I can see the value for this sensor in real time.

I would have thought that the pump would try to run for a longer period either for itself or for the Lexia.

I have added some photos including an ingenious 11mm ring spanner that opens so that it can be placed around the pipe. This makes dismantling the mechanical connections to the pump a simple affair and preserves the condition of the gland nut.

https://dl.dropboxusercontent.com/u/145 ... G_0224.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0232.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0233.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0235.JPG
https://dl.dropboxusercontent.com/u/145 ... G_0236.JPG

Looking at photo 232 (Date) and 224 (tear off part no label) it would indicate that the pump was replaced in 2010. The car is a 2006 Mk 2.

Is it possible that the car has a fault outside of the pump and ECU?

I will keep the forum updated until I succeed or give up and transport to an independent Citroen Repairer.

Many thanks for contributions.

[Gibbo2286]

Bleeding the system shouldn't be a problem, all that is needed is to raise the pressure in the tank to about half a bar then turn the steering lock to lock a few times and it self bleeds, the motor only runs for a few seconds at a time so if you can hear it doing that it's probably ok.

[howardaskew]

Gibbo,

I think it runs for about 5 seconds. The Steering pump is electric. I understand that moving the steering from lock to lock will help bleed the power steering but this is separate to the Suspension system.
They both share the same reservoir and the low pressure feed pipework has some parts in common but the high pressure systems are separate.

I used an Eazibleed system connected to a Tyre about 25psi to try and pressurise the system. This is more than the 0.5 BAR but I do believe that the system runs at a much higher PSI to raise the car.

Would you force the pump to run (whilst pressurised) Gibbo or would you be more patient with it?

Many thanks,

Howard

[Gibbo2286]

Sorry I forgot that you had electric power steering I was thinking of my own 2004 C5 I wouldn't however recommend raising the tank pressure to 25psi, plastic tanks are not designed to withstand too much and you might pop the welded seams.

You could try making the pump run longer by running a live to the third connector on the pump but it may not give any better results, trial and error I guess.

[howardaskew]

Gibbo,

I would be surprised if the tank would pop at 25 PSI. The pressure would be air rather than hydraulic oil.
I believe that when the car is lowered that the tank can pressurise with hydraulic oil. So I believe that the tank can withstand much higher pressures.

I could be wrong but we should soon find out.

Again many thanks for offering sound advice.

Howard