Citroen C4 Grand Picasso rear Suspension failure

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andybee
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Joined: 17 Oct 2020, 12:02

Citroen C4 Grand Picasso rear Suspension failure

Post by andybee »

Hi all,

I'm new to this site so i apologise if this subject has been raised numerous times before!

My C4GP (2009 Exclusive) has had suspension problems for a little while. Basically each morning i have come out to the car and the rear end is right down on the floor. Usually by unlocking the car the compressor fires up and up goes the car. I can only guess that there has been a leak in one of the airbags causing this? However, i came back to the car at the end of my day at work yesterday, unlocked the car and nothing. I have tried the button located in the boot and still nothing. When i put the key in the ignition i get "Suspension Faulty" on the screen.

Can anyone give me any suggestions as to what maybe wrong? I'm guessing either the compressor has given up (although this was replaced under warranty 5 years ago by the Citroen dealer that i bought the car from) or is it something more straightforward.

Any ideas would be gratefully received as i am now without a car!!!

Thanks all.
Last edited by GiveMeABreak on 17 Oct 2020, 13:34, edited 1 time in total.
Reason: Moved to Citroen Tech Forum

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GiveMeABreak
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Re: Citroen C4 Grand Picasso rear Suspension failure

Post by GiveMeABreak »

Pop your VIN up please (Automatically Masked on submission) so I can see exactly what you have, but in all honesty, it would be better to obtain the exact fault codes from a diagnostic so we can get an idea of what is wrong with it.

If you can hear the compressor working, then it won't be the compressor relay, ff not, check the relay.
If the compressor is operating, but the car is not raising in one side, then it may be a leak in the spring / cushion on that side.
If it's not raising on either side and you can't hear the compressor and it's not the relay, then it's likely to be the compressor.

But fault codes will be helpful.

andybee
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Joined: 17 Oct 2020, 12:02

Re: Citroen C4 Grand Picasso rear Suspension failure

Post by andybee »

Hi Marc,

Thanks so much for your reply. I'll get the VIN for you later on if that's ok. Whereabouts would the relay be located? The compressor is definitely not running so i'd like to check the relay first.

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GiveMeABreak
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Re: Citroen C4 Grand Picasso rear Suspension failure

Post by GiveMeABreak »

That's the bad news!

The relay is built onto the circuit board on the Suspension ECU that is contained under the rear left passenger floor well.

The relays are actually three or four MOSFET transistors soldered onto the underside of the board itself.

As for fuses, it may be worth checking those too:
MF8 is the 50A Maxi Fuse that supplies the suspension ECU.
F10 in the BSI (15A) is the suspension Control Unit.
F4 10A in the BSI is for the fuel additive pump - photochromic interior rear view mirror - suspension control unit - driver´s aircon control panel - multimedia assembly