XM Stop Warning Light Woes

pavesa · Unread post by **pavesa** » 28 Feb 2005, 18:53

For the last month or so my XM (1994 2 litre petrol turbo) has had this strange thing where when either accelerating other than extremely gently, particularly from standstill going up a hill, the stop warning light comes on.
I've had had this light come on before where one of the fluid levels is low but they all seem fine - in fact it started doing it right after a service.
It's almost as if the suspension is losing pressure slightly maybe as the weight is thrown back slightly when it accelerates. It has the original spheres which despite 105,000 miles my mechanic assures me are fine, and certainly it still runs very smoothly and the hydraulic pump isn't constantly cutting in suggesting the accumulator sphere is fine. It does brake absolutely fine and nothing feels amiss.
My mechanic has a theory that this may be something to do with the ABS. Any views on whether it may be (seems unlikely to me as the problem happens when accelerating not braking), or maybe someone can suggest what might be causing the problem?
Thanks
Andrew

pavesa · Unread post by **pavesa** » 28 Feb 2005, 18:55

I should add that it kinda flickers on and then goes out again after a moment!

oilyspanner · Unread post by **oilyspanner** » 28 Feb 2005, 19:03

I had a similar problem on my BX, it turned out to be a weak HP pump, I was getting the STOP lamp combined with the low brake pressure lamp flashing when turning right, when heavily braking and over undulating roads, a newer pump cured it, intewrestingly the problem only really showed itself after servicing the LHM, probably the new stuff is a bit thicker.
Stewart

pavesa · Unread post by **pavesa** » 28 Feb 2005, 19:07

Hi oilyspanner, thanks for the suggestion, I'll try and find out if they use the genuine Citroen LHM fluid, the fact that it started after a service fits with your suggestion.

Unread post by **RichardW** » 28 Feb 2005, 19:09

Do any other lights come on at the same time, or just the suspension light?
If just the suspension light, then I would disconnect the level sensor on the tank (bridge it out if necessary to make the light go out) and then see what happens. This will confirm either the level or pressure sensor as the trigger. Changing out the relevant sensor will then reveal a real fault or a sensor fault. A real fault in the pressure may be more difficult to rectify.
What was done at the service? Maybe it is low oil pressure, caused by a missing/malfunctioning non return valve in the oil filter?

pavesa · Unread post by **pavesa** » 28 Feb 2005, 19:15

No other lights, just the "! Stop" light. The service was just a regular service, normally I keep the invoice, but I don't seem to have this one..!

pavesa · Unread post by **pavesa** » 28 Feb 2005, 19:17

RichardW, Occasionally, the ABS light goes out and then lights up again when the car starts from cold, but turning off the ignition and restarting the engine cures it...