xantia bsi unit

[allanmc]

Hi looking for a bit of help I have a Xantia 2 series 110 hdi and if the car is left for 2 days the battery is dead an auto spark said that it was the BSI unit that was faulty but on the FCF they are saying this might not be the case thanks
allan

[noz]

Hi allan,

Welcome to club-xm. I hope we can help you to trace your problem.

Can we start with some basics? Do you have a multimeter or any kind of meter that can measure current? If not, do you have a neighbour or relative from whom you could borrow one? If you do not have one and cannot borrow one then fault finding is going to be difficult if not impossible.

If you do have one or can borrow one then remove the positive terminal from the battery and put the meter leads one on the battery terminal and one on the cable you have just removed. Set the meter to read somewhere in the region of 10 Amps at full scale. In this way any current being consumed in the car must pass through the meter so you can see whats happening. With everything switched off, all the doors closed and the ignition switch removed from the ignition, what does the ammeter say? It should read int he region of millamps (mA). This would normally be just the alarm and/or the remote plipper controller. If the current being drawinwith everything switched off is in the region of several amps then you do have a leakage problem. If there's no (or very little ) current being drawn then it points to a duff battery. Batteries are strange in that when they are on the way out they can appear to charge and the terminal voltage can rise to 12-14v but the charge does not last very long.

If the former is the case, come back and let us know and we'll talk you through the next steps. If the latter, try and borrow a battery of the right type and try it for a few days. If the problem disappears the the battery was the problem. If it remains then come back as I said above and we'll try the next test.

Cheers

noz

[allanmc]

Hi Noz, thanks for getting back to me so soon, right I can now tell you a bit more about my problem, you said to remove the Possitive lead well I have already done this with the Negative lead and the results were, with the meter set to the 10 amp range it read 70 now I am unsure what that means but been told this is too high anyway started to draw fuses and when I got to the no.25 fuse the meter went to zero this fuse on this fuse is the CPH unit which I think is the BSI unit,clock, radio, cluster lights alarm lamp, outside temp. lamp, nearly everyone says its probably not the BSI and I hope there right. hope you can help

allan

[allanmc]

Sorry NOz should have said new battery and alternator checked
allan

[noz]

Hi allan,

OK, doing it with the negative lead is equally valid. I'm going to assume that 70 means 0.7A on that scale. It is unlikely to be 7A since the battery would run down in a matter of hours. (e.g. a 65Ah battery would last roughly 65/7= 9hours if drawing 7A continuously, in practice it would be even less). Therefore at 0.7A continuous draw you'd expect somewhere in the region of 90hrs or a little under 4 days. One would expect to be able to leave the car unstarted for at least a couple of weeks and still be able to start it. Therefore 0.7A is too much and something is drawing current when it should not.

Unfortunately I don't have a wiring diagram for any of the Xantias so the next bit isn't going to be easy.

Excusing my ignorance but what is the CPH unit? Is it part of the multiplexing system?

I've attached the section of the XM multiplexing wiring diagrams concerning the instruments you listed. I have no idea how close (or not) this will be to the Xantia wiring but its worth a shot.

Where abouts in the country are you? I have a Lexia which can be plugged into the car to see if we candetermine the fault from the ecu(s). However, that would only be practical if you were reasonably close to me.

cheers

noz

[allanmc]

Hi Noz, right I am not sure about the amp readings I can only tell you that if I leave the car from today until saturday it wont start, next I can only say that I think it is the BSI thats what the citroen dealer calls it and says it is behind the pasenger glove box now the reason I am calling it the CPH is that in the hand book in the list of fuses thats where I found it, but you now have me wondering if thats what it is, sorry
allan

[allanmc]

Noz, I think it must be past my bed time I am not thinking right I am in Cumbernauld Scotland thanks
allan

[noz]

Hi Allan,

Well in that case you're not far from me at all. If you're willing we can plug it into the Lexia to see what it says abou the problem. Please send me a PM if you want to meet up.

cheers

noz

[allanmc]

Hi Noz, you asked me the other day if I wanted to bring the car over to you to plug it into the Lexia which I would appreciate very much and asked me to send a PM couldnt see that on the page but sent an e-mail now I dont know if you recieved it or not or you might be a bit busy hope you dont mind me sending this message
allan