Suspension Woes

carpy · Post by **carpy** » 16 Jul 2011, 01:19

My 2001 2.0 Hdi C5 suspension doesn't seem to be working anymore. After not driving it for a week I jumped in and promptly broke the bottom of the rear bumper on a speed bump. The front raised once when I used the adjusting switch but now there seems to be no movement at all and I haven't got a clue what to do. Any help please.
Thanks

Clogzz · Post by **Clogzz** » 16 Jul 2011, 14:03

First look at the suspension fuse, number 8 of 40 Amps.
The fuse box needs pulling out to reach the big fuses facing the battery.

carpy · Post by **carpy** » 16 Jul 2011, 18:37

Thanks, will do

carpy · Post by **carpy** » 16 Jul 2011, 19:31

Fuses checked out ok so back to square one I'm afraid.
Any more ideas please

Post by **myglaren** » 16 Jul 2011, 19:57

I'm sure there was a similar question raised recently that was caused by burned our/corroded wiring in the pump motor.

Did you check the fuses with any test instruments? They can develop fine breaks that aren't visible.
A check for voltage on either side of the fuse would help.

Clogzz · Post by **Clogzz** » 17 Jul 2011, 12:20

Was here, picture on second page:
http://www.frenchcarforum.co.uk/forum/v ... hp?t=35720

carpy · Post by **carpy** » 17 Jul 2011, 17:47

Many thanks for the replies. Can't look at anything today as it's absolutely pouring down and the car is outside. I have noticed that when you unlock the door the pump noise and suspension movement is no more. Nothing comes up on the dash warning panel as well. From reading the other post either the pump is getting no power or is broke. Can't understand how this can happen as it was working when the car was parked up.
Fed up now.

cachaciero · Post by **cachaciero** » 17 Jul 2011, 20:46

There is another possibility, if the BHI believes that both axles are "higher" than demanded the pump will not run. Now this implies a failure of both height sensors which is somewhat unlikely however the reference voltage that feeds the sensors may be fed by a common bit of wire.
Another possibility is the center console "low" switch permanently made, again if max low is set the pump will not run.
Finally the BHI has two distinct parts, the pump which is fed by the MAXI fuse which you have already checked and the logic / ECU part which I believe will have it's own fuse if the ECU is dead i.e blown fuse there will not be a signal to energise the pump. Sorry don't know where the second fuse is at the mo.
The pump can be energised separate to the logic.
On the pump connector there is a heavy contact which has 12V from the maxi fuse and a lighter contact which is the logic control input to the pump, if you connect 12V to the heavy terminal and 5V to the logic input the motor should run.

cachaciero

Post by **myglaren** » 17 Jul 2011, 22:52

Another possibility is the center console "low" switch permanently made, again if max low is set the pump will not run.

Which should be indicated at startup. Also a speed in excess of 6mph should override that.

cachaciero · Post by **cachaciero** » 18 Jul 2011, 09:57

myglaren wrote:
Another possibility is the center console "low" switch permanently made, again if max low is set the pump will not run.
Which should be indicated at startup. Also a speed in excess of 6mph should override that.

Yes I think you are probably right re the indication not so sure that speed would overide the "lower" switch if permanently selected, must try that next time I can find a suitable location

cachaciero

cachaciero · Post by **cachaciero** » 18 Jul 2011, 20:06

cachaciero wrote:
myglaren wrote:
Another possibility is the center console "low" switch permanently made, again if max low is set the pump will not run.
Which should be indicated at startup. Also a speed in excess of 6mph should override that.
Yes I think you are probably right re the indication not so sure that speed would overide the "lower" switch if permanently selected, must try that next time I can find a suitable location

cachaciero

Tried it today speed does override the button being held down so scratch that idea.

cachaciero

Post by **myglaren** » 18 Jul 2011, 20:14

cachaciero wrote:
cachaciero wrote:
myglaren wrote: Which should be indicated at startup. Also a speed in excess of 6mph should override that.
Yes I think you are probably right re the indication not so sure that speed would overide the "lower" switch if permanently selected, must try that next time I can find a suitable location

cachaciero
Tried it today speed does override the button being held down so scratch that idea.

cachaciero

Yep, done that on mine too.
Question is will it do it if there is a fault?

cachaciero · Post by **cachaciero** » 19 Jul 2011, 08:54

Ah...! thats woken up something. If you make any selection on the buttons if the ECU is working it will advise you of the height change. Now if you select raise and and it cannot achieve the correct height it will flag "Suspension Failure".

If doing a raise or lower you get no messages it would suggest that the ECU is dead or not talking for some reason.

cachaciero

carpy · Post by **carpy** » 19 Jul 2011, 22:36

Managed to check the big fuse in a small break in the weather this evening and current passes through it so it seems alright, checked across the fuse box where this fuse goes and with the engine running was getting permanent 12 volts, is this right. The car is completely slammed to the floor now. Any thoughts on what I should try next.
Thanks

cachaciero · Post by **cachaciero** » 19 Jul 2011, 23:06

Carpy

With respect there have been over the last four or five posts several things for you to check. Go sit in the car select high on the button see what indications you get then come back and tell us what you see.

cachaciero