65 Hard suspension Suspension
Citroen XM Internet Reference Version 1.0 93
3/3/99
65 Hard suspension
I am having trouble with ’hard’ suspension as well. It is soft when the engine is first turned on, but goes
hard when the car is driven. This implies an electrical problem, possibly with one of the sensors. I
made the mistake of taking the car (XM 2.0si 1990) to a citroen dealer (Sands of Bernham, near
Slough) to have the computer tested. They immediately recommended changing three of the spheres
(problem - I’ve had them all recharged recently, and there quote was *very* high). I insisted that they
test the computer, which revealed a problem with the accelerator sensor. At this point, the dealer was
stumped. The mechanic simply didn’t know what to do, and wanted to charge me labour for looking
through the manuals to find out how to proceed. I decided to get my car back, and was presented with
an 86 UK pound bill. (35 pounds for re-earthing the computer, 26 pounds for testing the computer, 10
pounds for a road test + parts + vat).
I paid up (mutter mutter), and have performed a bodge job which works fine until I sort my problem out.
I have connected the electro-magnetic valve (located almost directly under the driver’s feet on the RHS
rear of the front suspension sub frame) which switches the suspension between ’sport’ and ’normal’
directly to a 12v power source (the battery). By means of a switch I have located next to the stearing
wheel, I can now switch the suspension between ’sport’ and ’normal’ at will. I have disconnected the
computer from the electro-magnetic valve, but left everthing else intact. The handling of the car
doesn’t appear to be too adversely affected. There is more roll on corners, and the car ’rears up’
slightly during acceleration, but the car is still kept steady during braking and doesn’t bounce around
when being driven at speed on the motorways. The big plus, of course, is the ride is now lovely and soft
again.
I have gone on to test my accelerator sensor with a multimeter. It gives varying resistance readings as
the lever on it is moved, implying that it is still OK, although I’m not sure. I plan to try and source a
second hand sensor and to test the wires between the sensor and the computer.
On earlier models the electro-magnetic valve makes a very distinct click when it is turned on to engage
’normal’ suspension. If this isn’t heard, then it may be part of your problem James.
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I have all along suspected an electro-magnetic valve, but had not come across any other believer. On
both occasion that the ride has reverted to the magic carpet-ride, I (stupidly) moved the switch from Auto
to Sports and back again, to see if I could replecate the soft and magical ride. But no, it was back to the
old harsh ride with the rear almost seeming as if the spheres were empty. So it looks as though a
connection is not activating an electo-magnetic valve.
Finally, what is the little taped-up ballast resistor for, situated just in front of the box containing the
computers ?. I disconnected it and drove down the road. The suspension acted as if the ride-height was
on the high position. I quickly reconnected this little whatever.
Once again George, thanks for suggesting a whole new approch. It would also be interesting to hear the
responses from others with similar problems.
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