Xantia STOP light ’flickers’ during acceleration?

[MortyDK]

Dear all,

Before posting, I searched the forum and found several posts partially matching my symptoms – but, to my limited understanding of these matters, they did not seem to describe what my car has.

In short: Citroen Xantia 2000 2.0 16V 132 BHP petrol. During strong accelerations, the STOP light tends to ’flicker’ on. That is, it rapidly fades in and out, but is not fully illuminated. During normal driving there is nothing.

My first thought was some kind of liquid is low; and when it moves towards the back during acceleration, it registers as too low. But when driving uphill there is nothing (though admittedly, Denmark doesn't have anything really steep, we're a flat country. ) I looked at engine oil, and the LHM fluid. Those two are both good.

Background info:
It was recently at the mechanic, because it idled unsteadily. The mechanic cleaned the engine inlet, where there is an air density sensor, and updated the computer engine control idling settings. Other than that, no changes have been done to the car in good while.

Often the AC can cause similar symptoms, but I do not have the AC on. I am aware the AC might be on when the windows are dried / defrosted, but I also get the STOP light when the AC is off and cabin air is directed towards my legs.

What are you gents thinking – in which direction should I look? Thank you very much,

[isisalar]

Almost certainly the LHM level. check that and see. Get the car on the high setting and the orange disc in the sight chamber should be between the 2 red lines. Sounds like the level is just low enough the trigger the light under acceleration.

[citronut]

citro blood ( LHM ) level or maybe the pump belt is not tight enough,

or possibly dirty in tank filters

[Hell Razor5543]

While the STOP light is used in conjunction with other warnings, I agree that the first place to check is the LHM reservoir. Park the car on level ground, move the height lever all the way back to service high, and then (as previously stated) check where the orange disk is (NOT the brass disk lower down the indicator). It needs to be between the two red lines.

As well as the STOP light, is there any other lights lit (or flickering) at that time? If so, what is it? When you turn on the ignitions do all the relevant lights come on (so will go out again as they complete their test routines)?

[MortyDK]

Ohh, wow!! @isisalar, @citronut and @Hell Razor5543 tank you very, very much for the speedy and excellent replies.

Get the car on the high setting and the orange disc in the sight chamber should be between the 2 red lines. Sounds like the level is just low enough the trigger the light under acceleration.

Hmnn; I did check the LHM fluid, but perhaps I did it wrong. I went by the video instructions here and:

1. Let the car engine run and settle the car into normal operation height.
2. Cheked the LHM fluid, the pale orange plastic 'hat' was right in the middle of the two marker lines.

Is the car supposed to be at maximum height while checking LHM fluid?

Update/edit: Sorry, I'm not a native English speaker. The video referenced above says to have the car in "service high" while checking LHM fluid. So what is "service high" please, is it the setting one higher than normal operating height where gentle driving is still permitted? (I'm Danish, so my original manual is in Danish, and googling Citroen service high drowns in unrelated material.)

[MortyDK]

As well as the STOP light, is there any other lights lit (or flickering) at that time? If so, what is it? When you turn on the ignitions do all the relevant lights come on (so will go out again as they complete their test routines)?

No other warning lights go on or flicker during the STOP light flickering, it's only STOP that is on.

I'm .... not 110% sure that I don't have a 'dead' light during test rutine during ignition ... i.e. I could fail to notice that a light which used to be there during ignition isn't there any more. But I don't think so. I will check with the original service manual, and report back.

[DickieG]

To check the LHM level the suspension height lever should be in the highest possible position as in no further for the lever to move with the engine running.

[Hell Razor5543]

There are 4 height settings on the height control lever. Full forwards is Service Low (and releases most of the pressure), the next is for normal ride height, the next one from that is (sort of) off road, and the furthest back position is Service High. The LHM Level indicator is (as far as I am aware) a float, with the orange part being the indicator itself, and the brass part is the contact (you will see a pair of wires connected to the pipework cap on the reservoir).

The lights are difficult to explain, as there are several possible options (for example, some Xantias have the ability to monitor the front brake pads, and turn on a light when they are worn out, but other Xantias do not have that function). However, for a few seconds after the engine has started (and all other tests have been completed) there should be three lights on. They are the STOP light (in red), the brake warning light next to it (also in red), and on the other side the P brake indicator (also in red, to indicate the handbrake is on). Once the LHM system has achieved its working pressure (170bar, about 2,500 psi) the STOP and the brake warning light should go out.

EDIT; That video is correct, and service high is mentioned.

[citronut]

car on level ground, hight lever set to the highest setting, engine running, wait for the car to settle at its highest/fully up, now check the yellow/orage disc is between the two red bands,

as you say the disc is between the two red bands with the car at normal running height there is defiantly not enough citro blood in the tank

[MortyDK]

Dear isisalar, citronut, Hell Razor5543 and DickieG,

Thank you all very very much for your excellent help! Spot on, it was the LHM fluid that was low. Not being a native English speaker, I had misunderstood how to check the level. Now everything is good again, thanks to you all.

[Hell Razor5543]

Well done, and glad we could help. If you are unsure about anything, just ask. I believe that there are no such things as silly questions, just silly avoidable mistakes.

[myglaren]

Well done, and glad we could help. If you are unsure about anything, just ask. I believe that there are no such things as silly questions, just silly avoidable mistakes.

Exactly!

The forum exist to answer your questions.
Many of the members have experienced similar difficulties and the exchange of knowledge and experience benefits everyone.
Also, if you are unsure about anything, don't be afraid to ask for clarification - we do sometimes assume others know things that they are unaware of.

[citronut]

you now need to check were the lost fluid went to, look all along the underside of the car for any wet patch's, then report back if possible with photos