C5 suspension won't move

[au375]

C5 2.2 Hdi 2002 130,000 miles
Two problems probably unconnected.
1) Rear foglights do not work 99.9% of time. Extensive strip down of ECU in glovebox made them work once, but never again. No apparent dry joints/poor connections.
2) In spite of foglight problem, car went for MOT. Suspect garage put suspension on 'High', because after raising the rear wheeels off the ramp for inspection the suspension would not drop. The pump no longer runs.
Could these faults be connected. Any ideas?
I do not want to spent £700 at a main dealer for a new pump. If I fitted a secondhand one would it work at all without re-programming?
I'm stuck so any help much appreciated.

[Clogzz]

Fog lights and suspension have different ECU's, so the faults are not related.
The pump is for lifting the car only, not for dropping it back to normal height.
Dropping is done by electrovalves under the LDS tank, and controlled by the suspension ECU.
Check the connector at the front of the ECU behind the headlight.
Those in the know disconnect it to prevent the pump from turning.
When disconnected, the electrovalves don’t work either.
A lot of foibles can be cured by disconnecting the battery.

[cachaciero]

First check the maxi fuse at the front of the Engine Relay unit. Blowing the pump fuse is an not uncommon fault.

@clogz

There are two supplies to the BHI a heavy one for the pump and a separate lighter one for the electronics which includes the electrovalves. I am pretty sure that with the pump supply out low suspension can still be selected and the lower EV will open. (Not something that one would want to do unless safely at home

cachaciero

[sportingfiat]

when i had exhaust done on my old c5 estate the garage knocked one of the height sensors off and the pump ran till it blew the fuse

might be a loose connector

[Jerome3]

After washing my car for mot in the high position (to get the hard to reach places) parked the old lady up then took her out this morn to go to mot and the suspension wouldn't move neither up nor down no noise coming from pump
Help!!!

[Peter.N.]

I assume its stuck in low, sounds as though you have got some water in the electrics, may be OK when it dries out.

Peter

[cachaciero]

If it's low and the pump doesn't run then it's probably the Maxi Fuse (under the injection ECU) that supplies the pump motor a relatively common failure.

cachaciero

[Jerome3]

Don't suppose you have a pic of the maxi fuse position?

[Clogzz]

Fuse 8, 40 Amps.

[JT]

Hi Clogz,
I have a similar problem with the hydraulic pump on a 2006 C5.
It has hydractive 3 suspension.
The car is down to its lowest but not a kick out of the pump.
On the dashboard display when I push the button to raise the car the message is "Permission Not Granted".
I suspected a fuse at first but could not find any blown fuses.
So was wondering where exactly is the maxi fuse in front of the engine relay unit.
Can't find this one.
Thanks.

[Jerome3]

I can confirm this fuse is blown will replace and update
Thanx

[JT]

Spot on clogz.
Problem solved.
Thanks a mil.

[myglaren]

If the fuse is OK, and even if it isn't, two failure modes are the relay that powers the pump burning out and the wiring on the pump motor failing due to corrosion. Either can blow the fuse.

There are some photo's somewhere on the forum of the latter on the forum, posted in the past few months.

Otherwise suspect the BSI. Sometimes removing the battery leads for a while can reset it but it is a bit of a long winded procedure and if performed incorrectly can result in even more problems.
Ideally needs to be in a garage and if the battery is at all suspect this should be charged overnight. A defective or discharged battery can cause a lot of headaches and may result it more problems after performing this procedure.

Drop the suspension to low (to prevent the pump running when you refit the battery).
Open the driver's window and remove the keys, close any doors.
Wait at least ten minutes, ideally half an hour.

Unclip the battery leads.
Short them together through a resistance - a festoon bulb is ideal - for a minute or so.
Short the battery leads together for a minute.

Wait at least half an hour.

Replace the battery and clip the leads on. Do not open the door or otherwise disturb the car.
Wait at least ten minutes.
Reach in through the window and put the sidelights on. Wait a few minutes, five to ten ideal.
Reach in and turn the ignition on but do not start the engine. Wait five minutes.
Start the engine and let it idle for five minutes.
Open the door, get in and operate the suspension buttons.

If all is well then you will need to retune the radio, reset the time and date, reset autolights and reset window controls.

[Jerome3]

Replaced the fuse and all was fine till today when it blew again got home and replaced it again suspension wouldn't move checked fuse and it had blown straight away

[Gibbo2286]

I've had a few of these pumps apart, they suffer with corrosion inside the electric motor and either keep blowing the fuses or burn the motor coils rendering the pump useless. There's a thread on here somewhere where I posted some pictures,