C5 X7 Suspension Height Issues

[jgra1]

all sorry to hijack this thread, should I start another?
I have only skimmed over it so far!

last night I had a suspension fault / max speed 55mph on the dash
the car is low but not completely grounded, the LDS tank is fairly full and no (obvious) leaks..
I removed the small fuse unit along side the battery and all fuses have continuity and all have +12V on both sides.. (the yellow 60A one doesn't seem to go anywhere, maybe for a V6 job?)
no pump noise when opening door etc.

I will put DiagB on later, but what else can I try to prove or disprove the pump works etc? just quick tests I can do during the day, or is there a way of getting the car up a bit so I can put it into storage? (need it at normal height for this) - height buttons don't work..

I checked the 4 mini fuses in that box too, all fine.
Cabin 15A suspension fuse fine

remember I fitted a secondhand engine fuse box recently due to mouse / car interaction..

Kenny will read your thread! looks like a world of pain and expense! - can I power that red relay somehow to see if pump works?

many thanks as always,
John

[jgra1]

Sus/
C1146
U1118 x 2
C1118
U2005

so, will put on ramps later and expect a knacked link on the rear Height Corrector (like every other Citroen I have had ! )

Interestingly, I started the car and was sure i could hear the pump, the buttons were working (but ineffective)

[GiveMeABreak]

Hi John

C1146 is the rear body height sensor fault.
U2005 - ignore - it is a ghost fault triggered upon interrogation of the suspension ECU when the car is stationary (speed receipt anomaly).
C1118 - not listed anywhere
U1118 - Fault absence of communication with the built-in systems interface: No signal

So I would focus on the rear height sensor - you don't want to hear about the other possibility so I'm not going to mention it as you don't have any of the other associated C codes with this one thankfully.

Whilst the car is in this situation, be VERY wary of getting underneath it as the car can drop like that whilst there are height correction issues as I'm sure you know

[jgra1]

hi Marc, thanks.
car is on ramps.. apart from a load of rust, nothing untoward with rear HC.. still attached to roll bar and moving ok.. what to do? car is about as low as it can get.. i honestly dont know if the pump is working or not, maybe I am hearing the PS pump... certainly all is quiet when engine off..

I guess I need to hot wire the pump relay by bridging those two pins..

[Hell Razor5543]

It is not unknown for the height corrector to fail internally (for example, the pins are square section, but the holes in the circuit board are round, and the amount of solder holding them together is not great). The photos are no longer available on the forum (probably hosted by photobucket), but I have seen threads here where people have carefully opened up an H/C, cleaned up and re-soldered the connections, thereby resolving the issue.

[GiveMeABreak]

hi Marc, thanks.
car is on ramps.. apart from a load of rust, nothing untoward with rear HC.. still attached to roll bar and moving ok.. what to do? car is about as low as it can get.. i honestly dont know if the pump is working or not, maybe I am hearing the PS pump... certainly all is quiet when engine off..

I guess I need to hot wire the pump relay by bridging those two pins..

So my thoughts...

When I had this issue - driving along with the same warning, tried raising and lowering the suspension and often nothing - occasionally it would work but mostly not.

Also my directional headlights went into default mode (non-directional) as there was a height anomaly of course.

Took it to my dealers, sods law it went up and down - but then luckily on a further few attempts it stopped again. So left it with them and they changed both the height correctors under warranty - problem solved.

These height correctors are only analogue, so it just sends basic data to the suspension ECU incorporated into the BHI. But if the data is corrupt it might be normal not to hear the pump if the suspension ECU thinks the height level is ok - until it then gets a completely different value and puts the warning up - so the point being these things can be intermittent in the data they are outputting.

The potentiometer tracks can wear out, so I wouldn't bother attempting to repair these.

[MGmike]

Hi John,
someone nicked your post while I was typing

no worries hijacking the thread as mine is know fixed.
It does sound like your pump is the issue but there are a couple of things you can check to confirm. Unfortunately, once a quick Lexia check is done, you will probably need the front bumper off!

So, first up, check DiagB to ensure the pump ECU is communicating. Mine came up with a communication error and this indicates the BHI electronics mounted on top of the pump is U/S. (from the other posts it looks like yours is okay )

Then I'm afraid it's bumper off and (if the X7 is similar to the C6) there is a relay on the side of the radiator that feeds the power from the maxi fuse to the pump. You might hear this click when operated or connect a meter to the two pin plug at the pump. The single connector plug just above the power feed on the motor is a control signal from the ECU and should have 12v on when the pump is asked to run (i think). Check this when you are sure the pump should be running. I did this by blipping the key fob as the suspension runs on a C6 as soon as the doors are unlocked. If all that seems okay you'll more than likely have a failed pump motor.

Now you are this deep you can take the end plate off the motor and see if the brushes are worn, it's mouthing plate is burnt or there been some sort of winding failure.

Best of luck...
MGmike

[GiveMeABreak]

I moved this into a separate thread (I've also deleted your duplicate post on the other thread for you).

[MGmike]

ooo you're far to tidy for me

Thanks
Marc

[jgra1]

thanks Mike and Marc and James!

false alarm!

I took dogbone off rear HC, and pulled the plug to the hydraulic unit, was just a bit bored.. nothing too unusual
I found the maroon relay, and managed to separate it's plug from it, and bridge the two pins 3 and 5 .. nothing..
I had given up by then, but took one more look at the small fuse board, and to my glee, the green fuse at the end was toast! it wasn't obvious at first - now bear in mind this morning I tested had had continuity through all fuses! and had 12V at both posts of all fuses! (and still had) that makes my brain hurt - can someone explain?

so, at least I could bridge the broken fuse, pump came on, set the car to high and went back and bridged some more! now the car has made it to it's summer storage, I can take the pump off at leisure and get at them brushes!

I think my error codes were the same as Kennys' Marc,
Sus/
C1146
U1118 x 2
C1118 U2118 probably
U2005

for my next trick it's P1445 and a bottle and some access issues