S1 Xantia V6 - no start, no central locking

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CitroJim
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

Simon, sorry, can you help me and concisely and briefly tell me exactly what circuit diagrams you'd like and I'll try to get them done as soon as I can...

Doing the above will help me greatly and save a good bit of what is going to be very precious time today...
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Hi Jim,

Don't fret too much if you're busy today - remember I'm at work during the day anyway so I can't do anything except muse about the possible causes of the problem until I get home. :-D

I think the key is finding why power is missing to the clock, radio and central locking, and why they seem to be common. I know the loss of power to the clock is the same fault because the clock came back to life when everything started working and then died again when it stopped. I also have a reasonable suspicion that the current drain from the door lock actuators via the central locking is what is pulling down the voltage of the common feed between these different devices that seem to share a feed or earth. It also seems to be a permanent live (or earth) that is faulty because the central locking runs on permanent live, and so does the clock. I can tell the permanent live of the radio is missing as well because the anti-theft light on the radio is not flashing as it would be if it had a permanent live. The flashing light from the alarm LED is still working but is very weak.

Of the diagrams you've sent me, I could also do with the wiring location diagram for the keypad. (you sent the schematic and Harness diagrams but not the location)

For the Alarm and Central locking you sent only the schematics but I need the wiring location diagrams for them as well and possibly the harness diagrams. It's not clear from what you said whether the generic central locking diagram you sent is correct for the V6 with an alarm ? On a model with an alarm, is the alarm a separate ECU or does it replace the central locking ECU of a model with no alarm ?

Diagrams for the radio and clock would be nice too but as long as I have full diagrams including locations for the central locking, keypad and alarm units I should have enough to find it.

What I still don't know yet is whether the problem is with a permanent live, or whether its a ground return - figuring this out will help me narrow down the problem, so what I'm going to try tonight (assuming I don't have any further diagrams to work with by then) is lift the immobiliser keypad out and check the power and ground to that - I suspect that whilst the immobiliser is getting enough voltage to light up the lights that it doesn't have enough to communicate with the engine ECU - this would be the case particularly if the keypad had a bad earth because the data line to the ecu is probably 5v TTL, and if the ground is riding high due to a partial earth return failure they would not communicate as the TTL signalling voltage would be out of range.

I'm also going to try to remove the radio so I can get to the back of the radio and clock to take measurements to find whether it is permanent live or ground that is missing. If it's ground I should be able to bodge a workaround fairly easily.

Off the top of your head, can you tell me the physical locations of the central locking ECU, and alarm ECU ? I have no idea where these are at the moment, I suspect they may be in the centre console but if I can positively identify them and check voltages on them I may make some further progress. :)

Also if anyone else has a late Series 1 owners manual I would still appreciate a photo of the fuse numbers, especially the interior fuse box. Although all the fuses test OK I have not measured the voltages on the fuses, as it is pointless to do so when I don't know what each fuse is for... but if I knew what each fuse was for some useful voltage measurements could be taken on the fuses themselves.
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Re: S1 Xantia V6 - no start, no central locking

Post by Chris570 »

The Alarm ECU for the s1 is under the passengers seat.

The central locking ECU on an early S1 is behind the handbrake, not sure if it stayed there or not.
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Chris570 wrote:The Alarm ECU for the s1 is under the passengers seat.

The central locking ECU on an early S1 is behind the handbrake, not sure if it stayed there or not.
Thanks Chris, that's very helpful. :)

I think I have seen the ECU behind the hand brake previously when looking for the cruise control. On a Series 2 its the cruise control ECU that sits behind the hand brake below the rear wiper switches (since central locking is handled by the CPH behind the glove box) but on the Series 1 cruise control is under the drivers seat, and it definitely is on this car as I have accessed it before. Given how easy it is to access that behind the hand brake location and how central (ha) the central locking seems to be to the problem, I'll definitely start there tonight. If the Alarm ECU is under the passenger seat I think I'll leave that one for now unless I really need to access it! :wink:
Last edited by Mandrake on 03 Feb 2016, 10:44, edited 1 time in total.
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

Bloody hell Simon, I asked for a brief and concise list, not another sodding dissertation :lol:

I'll try to get the diagrams before the end of the afternoon...
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

CitroJim wrote:Bloody hell Simon, I asked for a brief and concise list, not another sodding dissertation :lol:

I'll try to get the diagrams before the end of the afternoon...
Sorry Jim, but you should know me by now... :-D

I really appreciate the help - I feel so helpless when I don't have sufficient information/circuit diagrams etc to troubleshoot a problem like this - it frustrates me no end that I have Sedre which has all wiring diagrams for a S2 Xantia, but nothing for a S1... some of the diagrams are the same or similar enough that I could get by, but the central locking, alarm and immobiliser are exactly the things that are completely different between S1 and S2! #-o Kind of wish I still had a S2 to be honest...
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Re: S1 Xantia V6 - no start, no central locking

Post by Stickyfinger »

Have you asked on the Activa group on Facebook ?
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Re: S1 Xantia V6 - no start, no central locking

Post by Chris570 »

Surely a simple live and earth check and then you can apply whatever is needed, then worry about it later.
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Re: S1 Xantia V6 - no start, no central locking

Post by ecohouse1 »

Hi Simon, It will be interesting to see how you get on. I am having a similar issue with my S2 TD Xantia - it doesnt have the pad, just a key symbol light that flashes and beeps on the dash if the key is not recognised, I am getting "permanent fault - no response from Engine ECU" from the Lexia. I lost the engine temp gauge and speedo more or less at the same time so suspect an earth or supply issue. I don't think I will have time to look at mine til Saturday. Mine came back to life on sunday and I restarted it 4 times with no issues, drove it 20 miles (luckily to my house!) and after leaving for 30 minutes, got the immobiliser fault again. Speedo & Temp gauge never came back to life even during the drive back. Good luck with yours and I will let you you know how I get on. Cheers, Alan
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

Mandrake wrote: Sorry Jim, but you should know me by now... :-D
I do and you know I'm only joking with my little comments... :-D

As soon as I can snatch a spare few minutes with my scanner I'll do the necessary...

Unless Alasdair's FB group can come up with the goods before then, worth a try, it is a very popular and busy group...
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Chris570 wrote:Surely a simple live and earth check and then you can apply whatever is needed, then worry about it later.
Simple, if you know where to look maybe...

Until you told me, I didn't even know where the central locking ECU was located. If I can't physically find something I can't measure it...that's where the wiring location diagrams come in handy.

From a basic circuit design perspective car wiring is pretty simple and not that complicated to troubleshoot (compared to something like an electronic appliance) however the difficulty is always in trying to figure out where something is actually physically located and where in the rats nest wiring harness its wiring runs, and what wiring it shares with other circuits, like common earths. All of which requires diagrams.

Difficulty getting physical access to some places you would like to measure even if you know where they are is a problem too, so the more information I have on paper the less poking about in the dark in difficult to access locations I need to do...

Now I know where the central locking ECU is located I have a good place to start even with the diagrams I already have.
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Jim you're a star :-D

I'm armed with a big wad of print outs to take home with me... :)

You really ought to save a permanent copy of those somewhere and add it to the useful threads section!

Looking at the clock wiring I see a potential source of trouble already - B002 which is some sort of bus bar located near the pedals ??!

The circuit for the clock is really simple, so if measuring on the central locking ECU doesn't give any clues I think the B001 and B002 junctions will be my next port of call...

Also just noticed that F25 is shared between the clock, the radio, and the positive feed to the alarm LED! Bingo... (The alarm itself is powered through a different fuse, only the dash LED is powered through F25, and that LED is very weak) The ceiling infra-red receiver also seems to be powered by F25.

Who wants to bet that its a dry joint on the back of F25 in the fuse box...is the drivers fuse box difficult to get out to solder on the back side of it ?
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Re: S1 Xantia V6 - no start, no central locking

Post by xantia_v6 »

Mandrake wrote: Who wants to bet that its a dry joint on the back of F25 in the fuse box...is the drivers fuse box difficult to get out to solder on the back side of it ?
I think it comes loose by pulling a plastic tab (dismantling of dash not required), but the bulky wiring makes it tricky to pull out. There are 2 PCBs back-to-back, and it seems to be the soldered joints of the pins connecting these together that fail, due to thermal cycling and metal fatigue of the solder.

BTW, the clock can be carefully prised out form the front without removing the radio.
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Well I've narrowed the problem down to a very high resistance feed from the 40 amp maxi fuse "D" in the engine bay fuse box, to the "shunt" in the cabin fuse box, which among other things feeds fuse F25, so I was right that there is no power from F25, which should be a permanent live. :)

When the shunt is removed I can measure 12v on the feed side of it however when connected I measure about 0.02v....so clearly a very high resistance there. Although I haven't tried it, I suspect if I ran a temporary alternative feed to the shunt everything would spring into life.

So it's either a bad connection in one of the fuse boxes, or the wire that runs around under the radiator is corroded.... I'm hoping like hell that its a dry joint in the cabin fuse box and not the infamous wire bundle under the radiator, hence tackling the fuse box first!
xantia_v6 wrote:
Mandrake wrote: Who wants to bet that its a dry joint on the back of F25 in the fuse box...is the drivers fuse box difficult to get out to solder on the back side of it ?
I think it comes loose by pulling a plastic tab (dismantling of dash not required), but the bulky wiring makes it tricky to pull out. There are 2 PCBs back-to-back, and it seems to be the soldered joints of the pins connecting these together that fail, due to thermal cycling and metal fatigue of the solder.
Coincidentally I'm stuck trying to remove the fuse box right now:

Image

I've pulled the red tab but it's unclear to me whether it's necessary split the box in half by releasing the clips before the rest can be removed, or whether the box as a whole can drop out and be unplugged at the top ? I just realised that if the box does need to be split that I'll have to pull out all the fuses. #-o (Hence taking a photo of where they belong, in the absence of an owners manual...)

Can anyone confirm whether removing all the fuses and splitting the box open is necessary to get it out, or whether there is something else holding it to the chassis that I can't see that needs releasing ?

I can see two large plugs on the top side so I'm hoping that I can unplug and remove the entire box so I can bring it inside to solder in the comfort of the house... :twisted:

Any hints from anyone who has had it out before ? Taking a short break as the rain has arrived, despite clear skies being forecast tonight... [-X

PS does anyone know if 2 amps is right for F25 ? It seems awfully small for the number of things it is running.