c5 suspension wont rise...please read

crosser69 · Post by **crosser69** » 19 May 2011, 17:43

Decided to fit mudflaps to my facelift 55 plate c5 1.6hdi,when i did the rear one and removed the jack the car was on its backside,i opened the door and the car rose straight away,i did the front mudflap and again when i released the jack the car was down on the ground,i opened the door and nowt happened,i started the car and it was the same,car still on the floor,check a few forums and i found that the 6amp main fuse had blown on the side of the fusebox,i replaced it and it blew again,i replaced that one and the fuse is now fine but the car still wont rise,the suspension button inside still works fine and displays itself on the info dash.
Ive heard stories before of this happening and the suspension pump needed replacing...so any ideas or help would be grateful as the car has never failed me before on anything like this.

dnsey · Post by **dnsey** » 19 May 2011, 18:41

When you say that the button still works, what does it do?

If the car rises to full height and falls to low, but won't stay anywhere between the two, you probably have a problem with the height sensor - easy and fairly cheap

crosser69 · Post by **crosser69** » 19 May 2011, 18:43

The button works as in it shows on the small screen but the car itself is still on its bottom and wont go up

Clogzz · Post by **Clogzz** » 20 May 2011, 16:15

Is the pump running ?
If it does, put the suspension on the low setting first, until it stops running.
Then raise to normal level next.
The pump fuse is number 8, of 40 Amps.

crosser69 · Post by **crosser69** » 20 May 2011, 16:31

doesnt sound like pump is working at all,bit awkward to get connectors off pump,fuse is now ok.
pump would work before as soon as you opened door but now nothing at all,either when you open door or start car,i am wondering about getting 2nd hand pump but just wondered if there were any other tests that could be done or anyway of eliminating anything else

Clogzz · Post by **Clogzz** » 20 May 2011, 16:58

Simplest to try first is disconnecting the battery to reset the ECU.
Doors and windows shut except for driver’s window down.
About a minute of disconnection without touching doors or windows for a minute before and after.

crosser69 · Post by **crosser69** » 20 May 2011, 17:20

ok will try that and let you know

crosser69 · Post by **crosser69** » 20 May 2011, 17:45

tried that twice and no joy but did hear a slight wimper from the electronic suspension pump but the noise was dead slow instead of the usual noise it would make,will car have to be reprogrammed if i get 2nd hand pump?

dnsey · Post by **dnsey** » 21 May 2011, 08:30

It certainly sounds as though there's a problem with the pump, but I'm rather surprised that the display screen still reads normally. I'd have expected it to show 'Serious suspension problem', with a big cross through the height indication screen. Maybe some faults trigger the warning, and others don't...
Although it's awkward to get at, I'd be inclined to check the voltage at the pump itself (pre- and post-ECU). It may be that there's a high-resistance connection somewhere, dropping the voltage to the pump.

crosser69 · Post by **crosser69** » 21 May 2011, 09:22

ok well now i do need help,i know there is 3 wires attached,how do i go about checking thie,i take it one wire is earth,one will be the main power and the other a power from when the doors are opened?

Clogzz · Post by **Clogzz** » 21 May 2011, 11:49

The power wires are the two thick ones.
Don’t know what the thin one does, but not power.
It’s so difficult to reach there

that you may have to stick pins in the wires to get at the voltages.
There must be a relay for the pump in the fuse box, but don’t know which one.
If changing pumps, the electronics can be separated.

dnsey · Post by **dnsey** » 21 May 2011, 13:56

I presume the thin wire is a data stream to the pump ECU. Be careful not to connect it to anything else!
If the voltage on the thick wires is OK, I'd then separate the pump ECU from the pump proper and check the voltage there.
A final check is to completely disconnect the pump motor (electrically) and briefly try to power it directly. Should tell you all you need to know!

cachaciero · Post by **cachaciero** » 22 May 2011, 18:51

I don't know for sure but I suspect that the thin wire to the pump is a logic signal to switch the pump on, i.e the two heavy wires go to battery and earth and there is either a solid state switch or maybe a plain old relay built into the pump, so it will not be enough just to apply battery volts across the two heavy terminals. Of course I may be wrong...

cachaciero

crosser69 · Post by **crosser69** » 07 Jun 2011, 14:37

Im still on with it,managed to change the resister and the electronic bit on the back of the pump and still the same but now display comes up with 'suspenion faulty'.
ive checked the 2nd hand pump ive got and then runs spot on but when i try old pump with ecu disconnnected it hardly runs so im resuming that the pump itself is kerput,so next week when i have a ful day will take pump off,swop over ecu etc and put on,hopefully this will fix it,powere and earth ok and power going to trip wire to set pump off,will keep everyone updated.

Gibbo2286 · Post by **Gibbo2286** » 11 Jun 2011, 12:23

I've just stripped out the electric motor on one of these pumps, there was evidence of water ingress, the copper coils on the brush holder were covered in blue crud, one of them had blown.

I cleaned it up and soldered in a short length of copper wire to bridge the gap and the motor now runs on the bench and on the car but doesn't pump anything, it seems as though the connection between the motor and the pump shaft is either disconnected or broken.

Has anyone got a split diagram of the pump, I'm reluctant to split off the motor because I can't see from outside how the two are joined they don't simply pull apart.

If you care to tell me how to post a picture on here I'll show the damage. G.