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 »

I'll be very interested in the result Simon..
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Re: S1 Xantia V6 - no start, no central locking

Post by Old-Guy »

CitroJim wrote:
Mandrake wrote: I'm puzzled as to why that article shows removing the lower steering wheel cowl for this job ?
I found out, only after removing the lower cowl, when I did mine that it was unnecessary..
I'll put my hand up to the defective Wiki. I blindly followed the relevant thread, and not having the wit to notice that removing the cowl was unnecessary, duly included all that extra hassle when wrote I the Wiki... :oops:

Apologies to all those who followed me up the garden path; I'll edit the Wiki ASAP.

Jim, just to be absolutely clear: Step 1 Remove the Lower Column Cowl is unnecessary, as the connectors are accessible simply by starting from Step 2. Remove the Lower Trim Panel?
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

Old-Guy wrote: Jim, just to be absolutely clear: Step 1 Remove the Lower Column Cowl is unnecessary, as the connectors are accessible simply by starting from Step 2. Remove the Lower Trim Panel?
Guy, that's correct :-D
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Re: S1 Xantia V6 - no start, no central locking

Post by Old-Guy »

Garden Path removed!
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

I'm back! :-D

I was about to post last night that everything has been going wonderfully since the repairs, and they had - no electrical problems and the car was running beautifully. The engine had remained really zippy as well, so I think the corroded wire had been causing some minor issues up until the point where it finally let go. :)

However when I got home last night and tried to lock the car with the fob I noticed that it was deadlocking rather than just locking. [-X Because of the faulty wiring issue I had just fixed I had decided not to use the deadlocking for the time being in case something went wrong, as correct me if I'm wrong but failed power to the deadlocking ECU means a smashed window to get in if the car is deadlocked, even the key on the outside won't open it ?

I tried it multiple times - it would unlock with the fob, but locking would both lock and deadlock with a single button press instead of requiring a press on the second button to deadlock. Furthermore the deadlocking button would do nothing and although it was deadlocking the locks the blinkers would not flash like they normally do. Also the alarm light on the dashboard seemed to be completely dead. Hmm....

So while I had dinner I disconnected the battery for about 30 minutes to reset everything. After dinner I connected it back up and everything seemed to be working fine at first - I could lock and unlock without deadlocking, and now the deadlocking button on the remote was working again complete with dashboard light and flashing blinkers.

I then went for a drive to fill up with petrol and about a mile into the journey the doors locked themselves! :shock: Every time I tried to unlock the doors with the latch on the door the central locking would lock them all again. I pulled over in a car park and fiddled around and found it very intermittent - sometimes it would keep trying to lock the doors as soon as I unlocked them (even if a door was open) and sometimes it wouldn't. With a door open it would try to lock a couple of times then give up, I could then close the door and it would remain unlocked for a while but then lock. (Mental note - don't leave the keys in the car unattended!)

This morning I took out F27 for the central locking to disable it just in case it decides to deadlock all the doors and run my battery flat. I'm also thinking of renaming my car to "Christine"! :rofl2:

Anyone had this problem before ? I've been thinking about the problem and looking at the diagram that Jim provided earlier in this thread:

Image

My gut feeling is that I don't think the fault is actually related to the repairs I've done earlier, but that the fault lies in one of the front door switch assemblies labelled 6202 and 6207 in the diagrams above - or perhaps the wiring to the door. Any suggestions on the best way to tackle this problem ? It seems very intermittent and I don't fancy taking the door card off both doors unnecessarily, so if I can narrow it down to a particular door at least that would halve the problem...

I have a very vague recollection that we had the exact same problem in reverse on my Dad's Xantia - where it would keep unlocking when locked, and while it was 11 years ago and I don't remember what the exact cause was I do remember that it was not a broken wire. I think it was a problem in the switch assembly but can't remember the details...I also don't remember replacing the switch assembly so it might have been some contact cleaner in the switch or on the switch connector that we fixed it with...
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Re: S1 Xantia V6 - no start, no central locking

Post by RichardW »

Deadlocking won't stop you unlocking with the keys, it stops you unlocking the doors from the inside, ie if the scrotes try and jemmy the door open. This sort of thing is often associated with the ECU taking a bath.... have you checked no sign of water ingress under the passenger side front carpet (by getting under it - surface check no good). My next instinct would be broken wire(s) to the doors, but yours is not high mileage, so this seems unlikely, and it's not common on Xantia. Don't know if you can force back the trunking to see if any wires broken? Getting the door panels off is not hard if you've got a trim remover (well, apart from the lock buttons!). Not sure what this would show though? Maybe you could wire a lamp across the terminals to see where the lock command is coming from? Or unplug the switches to see if the fault goes away.
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

RichardW wrote:Deadlocking won't stop you unlocking with the keys, it stops you unlocking the doors from the inside, ie if the scrotes try and jemmy the door open.
Are you sure that the key barrel can unlock the deadlocking in the absence of power though ? I know that it can when there is power because it operates a switch that activates the central locking.. but with no power ? I've always avoided using deadlocking if I've known the car is not likely to be driven for more than a week for this reason...
This sort of thing is often associated with the ECU taking a bath.... have you checked no sign of water ingress under the passenger side front carpet (by getting under it - surface check no good).
I haven't looked under the carpet but I'll give it a check if I can't find any other cause. The ECU itself is not under the carpet though - the deadlocking ECU is up off the floor in the rear of the centre console below the rear window winder switches, but I suppose if that big connector on the front left corner of the passenger footwell got wet it might cause problems...
Getting the door panels off is not hard if you've got a trim remover (well, apart from the lock buttons!). Not sure what this would show though? Maybe you could wire a lamp across the terminals to see where the lock command is coming from? Or unplug the switches to see if the fault goes away.
Several of the switch contacts in the door lock assembly are normally closed contacts, if the switch contacts themselves or the pins on the connector to the switch unit were corroded those lines going open circuit would fool the ECU into thinking you were turning the key, or that the lock position was not what it thought it should be.

It's not clear from the diagram what every switch in the module is for though. My interpretation of the switches in 6202 are from left to right:

1) Motor limit stop switch - possibly involved in distinguishing between locked and deadlocked
2) Key barrel switch - tells the ECU when you turn the key left or right to lock/unlock
3 & 4) One of these is probably for the locking button and the other for detecting the position of the lock catch itself - but I'm not sure which is which!

I probably won't get time to look at this until the weekend but I think I'm going to have to do some meter testing on the switches to figure out their precise purposes. This can be done fairly easily back at the ECU connectors in the centre column thanks to the circuit diagram Jim provided! =D>

I suspect that the fix is probably going to turn out to be a good dose of contact cleaner in the switches and the switch assembly connector, which unfortunately means removing the door card, but if I can find which door it is that will halve the work.

Edit: looking at the rear doors I think I can work out what switch 3 and 4 are for on the front doors. The rear doors only have the limit stop switch for the motor and one other switch - that other switch must be the one that detects when the door is locked properly, and that is the same symbol as switch 4 on the front doors. So switch 3 must be for the interior lock button ? (Since the rear doors don't monitor the interior lock button with a switch)
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Re: S1 Xantia V6 - no start, no central locking

Post by RichardW »

I think the switch on the left is just a mechanical flip flop to set the drive direction of the motor. Other 3 I agree with - interestingly the door locked button only goes to the alarm on the front doors, although it appears to go to alarm and CL ECU on the rears....??? I can't see how deadlocking is activated - there doesn't appear to be a separate function in the door, but perhaps the ECU just sends a second 'on' signal to the motor to move it to deadlocked position. So if you were getting deadlocking on only one button press, then that would point the finger at the IR receiver or the ECU, as it doesn't appear there's anything else controlling deadlocking - unless one of the doors is jammed into deadlock position on the key (is that how it works - can't remember - hold the key and it will deadlock?)
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Didn't get any email notification of your reply so only just discovered this now Richard...
RichardW wrote:I think the switch on the left is just a mechanical flip flop to set the drive direction of the motor. Other 3 I agree with - interestingly the door locked button only goes to the alarm on the front doors, although it appears to go to alarm and CL ECU on the rears....???
Yes that is odd. I have the fuse out until the weekend (sorry Christine :lol: ) but I will do some meter testing on the weekend to find out exactly what each switch is doing - I did actually figure this all out in detail about 10 years ago when we had a similar problem with Dad's car but of course I've forgotten the finer details... I'll document it in this thread in case others find it useful, as central locking with a mind of its own does appear to be relatively common on older Xantias! :)
I can't see how deadlocking is activated - there doesn't appear to be a separate function in the door, but perhaps the ECU just sends a second 'on' signal to the motor to move it to deadlocked position. So if you were getting deadlocking on only one button press, then that would point the finger at the IR receiver or the ECU, as it doesn't appear there's anything else controlling deadlocking - unless one of the doors is jammed into deadlock position on the key (is that how it works - can't remember - hold the key and it will deadlock?)
Yes if you hold the key turned in the lock position for additional time it activates the deadlocking.

You got me thinking above and I think I've worked out how the deadlocking is achieved - there is only one motor in the door so deadlocking clearly must be the same motor turning further than the normal lock position. So it will be achieved through the use of the limit stop switch.

The switch will be in one position - "unlocked" when the door is fully unlocked and in the "locked" position when the door is either locked or deadlocked. When the ECU wishes to simply lock the door it applies power to the motor through the switch contact that is only closed when the door is unlocked. Thus as soon as the lock moves to the normal locked position power is removed by the switch and the locking mechanism stops there. When it wants to deadlock it then provides power to the other previously open contact which is now closed and the motor moves further into the deadlocking position.

If it wanted to it could actually move from unlocked to fully deadlocked in one move by applying power to both switch contacts at the same time, but the fact that you have to press one button then the other with a delay on the fob means that probably doesn't happen in practice.

To unlock the door it simply applies reverse polarity to the motor and provides power to the contact that is now closed, which goes open once the door is unlocked. Simple. :)

Another thought I have had is that the right hand most switch in the boxes in the diagram must be the door open switch that brings on the interior light - the rear doors do obviously bring on the interior light as well as the front doors, and although I have the fuse out of the central locking system the interior lights all still work with the doors! Obviously these interior light switches also go the alarm ECU, which is a separate ECU on a S1, and that still has power as it runs off a separate fuse.

So I think we can revise our front door switch list to: (left to right)

1) Locking/deadlocking motor limit stop switch
2) Key switch
3) Interior lock button switch
4) Door open/interior light switch

The rear doors only have 1 and 4.
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Re: S1 Xantia V6 - no start, no central locking

Post by RichardW »

On another thread Old-Guy wrote:I vaguely remember a thread some years back about a possible problem with water getting into the electronic IR receiver unit behind the dome.
Water in there might give the symptoms you've got...a leak from the aerial base perhaps? Worth popping it out to have a quick look.
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

Good suggestion - I had forgotten about the ceiling receiver. I don't think it's that but I'll unplug it and see if the random locking still occurs. Hoping for a fine weekend.... [-o<
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

No progress this weekend - I put the fuse for the Central locking back in on Saturday morning as I had to take extra passengers (and can't open the rear doors manually as their lock buttons don't work) and in typical fashion it will not play up now! The car was used a few times over the weekend with the fuse back in and not a whiff of a problem... :evil:

So I've decided to leave it for the moment and keep an eye on it - and try to remember not to close the doors with the keys inside just in case! #-o :roll:
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

You have spare keys don't you Simon?
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Re: S1 Xantia V6 - no start, no central locking

Post by Mandrake »

CitroJim wrote:You have spare keys don't you Simon?
I have a spare fob yes. But it's usually kept in the house.

I can just see myself locking the house door, starting the car, swinging the drivers door closed (as I usually do) while I went to open the gate and/or de-ice, only to hear a "click" locking me out of both the car and the house with the engine running. :rofl2:

Needless to say I will do my best not to shut the door with the keys inside, but habits are hard to break...
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Re: S1 Xantia V6 - no start, no central locking

Post by CitroJim »

Good point Simon.. I have a contingency for such an event happening to my keys...

Plus it's ever so easy to lock myself out of my house...