xantia dashboard STOP light

stevecritchlow · Post by **stevecritchlow** » 30 Dec 2005, 18:19

hi all, this is a follow up to an earlier post by myself, hoping for some more help.

I've got a 1997 mark two Xantia 2.1TD SX. Over the last week or so the large red STOP warning sign on the dash has been coming on intermittantly (but regularly). None of the other warning lights are showing to give me a clue, although I have checked that all these lights do function at start up.

I have checked all the likely culprits for a warning light. Oil, water and LHM are all fine, and I've recently changed the accumulator sphere but this hasn't helped.

I'm thinking that the fact I have the stop sign but no other warning suggests the ECU is picking up a signal notcoming directly from a sensor, so probably a short or earth fault.

I'm also suspicious of my brakes, although they perform perfectly, as I have recently worked on them to change the discs, and the light is freqently trigger by my braking whilst in motion (although not every time I brake, and sometimes without braking)

Any thoughts on possible causes chaps? Is there anything in the brakes which could cause an electrical fault that I could visually inspect?

Post by **zxTd** » 30 Dec 2005, 18:38

hmmm breaks so it was ok till you did this work??, break wear sensor wires?? poor connections or broken wire

AndersDK · Post by **AndersDK** » 30 Dec 2005, 19:21

The STOP lamp is not controlled by an ECU.

In fact its a rather simple circuit with a diode from each of the fatal warning lamps to the stop lamp.
I still believe you have a missing warning lamp when you get the STOP lamp - as no circuit or sensor can lit the STOP lamp alone.

The brake pads wear warnings wont set off the STOP lamp, but only a yellow warning lamp alone.

Post by **zxTd** » 30 Dec 2005, 19:33

The brake pad wear sensors "if fitted" are a major aspect of a warning system as are break lights/fog light/any fluid level/engine sensors/coolant fans/tyre pressure sensors and much more "dont look for the obvious a lost seal on the fuel cap can set the light on"

stevecritchlow · Post by **stevecritchlow** » 30 Dec 2005, 20:19

Right, making progress now!

thanks to Anders suggestion, I've looked again at the dash lights and guess what, the light for my front brake pad wear isn't working. Sorry for missing that earlier, and thanks to Anders

so, firstly I asume the warning light isn't illuminating simply because a bulb has gone??

I know my pads are OK, so is the STOP light coming on because of the bulb having blown on the pad wear warning, or should i assume the sensor requires replacment?? Is there a wear sensor on each side of the car??

Thanks
Steve

Post by **zxTd** » 30 Dec 2005, 20:28

wow you had buggered bulbs thats nice to know, some have sensor wires both sides

Post by **Peter.N.** » 30 Dec 2005, 21:11

If you are sure that the pads are OK, it may be that one of the sensor wires is rubbing on something which is earthing it, especially if the pads have recently been replaced and the wires not correctly routed.

Mandrake · Post by **Mandrake** » 30 Dec 2005, 21:16

If it is in doubt as to what lights will come on when the brake wear sensor triggers, (and whether they're working) why not try triggering it manually ?

With a front wheel off and the car supported, unplug one of the sensor wires from the little double connector near the strut, and poke a piece of wire into the hole and touch it onto the chassis somewhere, and have a look at the dash lights while the engine is running and see what lights come on.

Regards,
Simon

AndersDK · Post by **AndersDK** » 30 Dec 2005, 21:40

Each front brake pad (4 in all for both sides) has a wear warning sensor which can set off the one and same pad wear warning lamp. The rear does not have wear sensors.

I must admit that the pad wear warning light would have the nature you have seen : now it's there - now it's not - but you are sure to see it duing every trip you make once the pads are worn down to the warning limit.

But pad wear warnings does not set off the STOP light. Or should I say it does not do it on BX & CX at least.
Anyway - we are close to do some testing action now proposed by Simon 8)

stevecritchlow · Post by **stevecritchlow** » 31 Dec 2005, 08:37

heres a simple question to help me decide whether I am totally wrong with my current line of thinking.

Does / should the pad wear warning light come on at start up?

Mine doesn't, which I initially thought indicated a problem. However, on inspection all my pads and disks are very good. When i short out the wear sensors the warning does indeed light up, so the bulb and system appears OK. On closer reading of the owners manual, there is no suggestion that the wear light should illuminate on start up, and if this is right then i have no reason to suspect there is anything wrong with this system at all.

Mandrake · Post by **Mandrake** » 31 Dec 2005, 10:46

Looks like you can eliminate the brake pad wear sensors as a possible reason for the STOP light coming on then. Where that leaves you I don't know exactly.

Strangely enough on the way home tonight I saw the STOP light on my car flash on briefly a couple of times, and I quickly looked to see if it was the temperature light (the tiny red light at the top of the temp guage) which has come on before, but I could have sworn that light wasnt lit, so it seems as if I saw the STOP light come on by itself too.....

Regards,
Simon

KevMayer · Post by **KevMayer** » 03 Jan 2006, 23:47

I've just noticed on another topic someone suggesting that the STOP light will come on if the Aircon pressure is low. There's a pressure sensor somewhere near/in the dryer bottle apparently. If the pressure is low does this bring up our lamp ?

We need a reference table to list all the possible causes that make the STOP lamp appear.

Anybody know enough to put it together ?

cheers, Kev

stevecritchlow · Post by **stevecritchlow** » 07 Jan 2006, 07:12

UPDATE

Decided to take my car to my a recommended indepent specialist (S&M Motors in Stoke) who found some connectors in the loom, underneath the battery, which have been cleaned and rassembled. Apparently they are notorious for causing all sorts of electrical problems.

anyway, problem is now all sorted.

KevMayer · Post by **KevMayer** » 08 Jan 2006, 21:00

The connectors under the battery tray are.......... BITRON .. connections.

That BITRON keeps giving us jip !!

Mandrake · Post by **Mandrake** » 08 Jan 2006, 21:29

KevMayer wrote:The connectors under the battery tray are.......... BITRON .. connections.

That BITRON keeps giving us jip !!

Hang on, is it under the battery tray or under the left headlight ?

Regards,
Simon