Citroen C2 - dead electrics - No power to locks, interior light, ignition - everything dead

[napping]

Can you confirm by earth ring are you talking about the line i've highlighted in green?

Surely that "green ring" just marks the semiconductor inputs and outputs - it's not just an earth ring?

[wheeler]

I thought that was what you were talking about. Thats not an earth ring, it just means there is an internal connection to the BSI circuitry. Yes you can see 6 & 8 join internally but its not to a ring. If you look the majority of wires in that diagram that come out or go into the BSI connect to that 'ring' including CAN wires & direct battery lives.

EDIT: Napping got there just before me & beat me to it.

[Dormouse]

You are right. See what I mean about confusing layouts. Dots on lines are physical connections to me. If the Green ringed item is electronics why does it have solid lines and Dot connections when another shape of connector would define it clearer.

The more I look at the green ring the less sense it now makes. Dots on lines mean connections to me but that many connections don't make sense. Therefore I am well out on this one.

[wheeler]

See what I mean about confusing layouts. Dots on lines are physical connections to me. If the Green ringed item is electronics why does it have solid lines and Dot connections when another shape of connector would define it clearer.

Dots on lines mean connections to me but that many connections don't make sense.

I would agree that's the way i would normally see it too normally about the dots & solid lines however it appears that on PSA diagrams this also means connected to internal electronics
I will say though that out of all the vehicle manufacturers wiring diagrams i have used PSA's in my opinion are the best by miles.

What do you mean by earthing ring? Yes I would definitely confirm pins 6 & 8 have a good earth (I would check them under load if it was me). Has this not already been checked?

Yes, I checked them for continuity but not under load. How do I do that without the risk of frying the BSI?

OK so to load test them unplug the green connector then get a 21w bulb connected to the battery then earth the bulb using pins 6 & 8, make sure the bulb lights up nice & bright. A continuity check just shows there is a connection but not how good it is, even a resistance check is not that great, there could be a single strand of copper connecting the cable to the earth point & it will show 0.1 ohms but it may not be able to carry enough current lots of corrosion on the earth that show an ok resistance but as soon as any current is passed through it it cant cope.

[Dormouse]

I think "best" should be "of a bad bunch". Of wires.

[ozvtr]

So - the BSI plays dead unless BSM relay R6 or BSI relay R7 are bypassed. That suggests to me whatever triggers relays R6 and/or R7 isn't doing its job.

You did not by-pass R7. R7 is the only thing to power the instrument cluster. So you have stimulated something to turn R7 on (the signal from powering the BSM fuse F13 circuit). Again we are back to evidence that the BSI is not working.

The odometer not displaying whilst the tripometer does suggests there is no power to the circuit(s) that activates when a door is opened, etc - as usually the odometer will display before the key is inserted in the ignition switch.

Just looks like the BSI is "brain dead" to me. The trip info is stored in the instrument cluster but the ODO is "polled" by the BSI before it will be displayed. So, again evidence that the BSI is not talking to anyone.

So the problem appears to be related to the initiation stage where the power is available to the locks and the odometer. As Wheeler says, this could be a cable issue.

I don't think so. I think the fuse f13 in the BSM circuit is supplying power back to the BSI and powering up some of the BSI circuits (either directly or stimulating them to be powered up). The word here is powering. I don't see any evidence the BSI is "alive".
It appears I was wrong and the BSI-powers-up-the-BSM-which-powers-up-the-BSI theory is correct! What a b@ll ache! As I said the MK1 (CAN-VAN) system does not run this arrangement. There is no power running back to the BSI from the BSM. For some reason the CAN BUS feed back from the BSM to the BSI that everything is OK isn't good enough for the CAN-CAN setup?

Wheeler. There used to be circuit diagrams for the BSM and BSI for the CAN-VAN set ups. Are there diagrams for the CAN-CAN setup? I am not sure this will prove anything because some of the traces will go back to a "box with the symbol of an IC on it" on the BSI circuit...proving nothing (what's the box doing?).

Well I didn't get the answer that I expected by powering up the BSM F13 circuit but I do think it's another nail in the BSI's coffin.

[ozvtr]

So - the BSI plays dead unless BSM relay R6 or BSI relay R7 are bypassed. That suggests to me whatever triggers relays R6 and/or R7 isn't doing its job.

You did not by-pass R7. R7 is the only thing to power the instrument cluster. So you have stimulated something to turn R7 on (the signal from powering the BSM fuse F13 circuit). Again we are back to evidence that the BSI is not working.

Did you look at the instrument cluster when you powered up the BSM fuse F13? My statement above might be wrong if the instrument cluster does not activate.

[ozvtr]

Yes, putting power to the BSI F13 does by-pass R7 and apply power to the instrument cluster. But that doesn't prove anything. You could see that in the circuit diagram.
Again, the fact that power also powers up the BSM is interesting BUT you could see that in the circuit diagram too. Not much learnt there.

If the instrument cluster comes on when you power F13 in the BSM that interesting too but you aren't learning much about your fault.

I think the F13 labeling is a joke on the engineers behalf...no 13th floor in high rise!? No F13 in the user manual? If F13 blows...seek professional help, like the maxi fuses?

[wheeler]

Wheeler. There used to be circuit diagrams for the BSM and BSI for the CAN-VAN set ups. Are there diagrams for the CAN-CAN setup? I am not sure this will prove anything because some of the traces will go back to a "box with the symbol of an IC on it" on the BSI circuit...proving nothing (what's the box doing?).

I think this is the thing you mean? If so they are just as helpful as the specific circuit diagram. Just shows most of the connections going to an 'electronic box'.

[napping]

Yes, putting power to the BSI F13 does by-pass R7 and apply power to the instrument cluster. But that doesn't prove anything.

As either of the F13's (BSI and BSM sides) fire up the BSI when 12v is applied to each, this is an indicator that the relays R6 and R7 aren't getting power and that both relays are probably OK (as it is unlikely both relays would fail).
As the wiring diagram shows R6 is driven from the BSM and R7 driven from the BSI, which suggests the problem lies in whatever "triggers/powers" relay R6 on the BSM and R7 on the BSI after the doors are unlocked or opened. I think this is progress, but I don't know what is the next meaningful check, although I will go back and check the earths with a 12v load test as Wheeler suggests.

[napping]

Did you look at the instrument cluster when you powered up the BSM fuse F13? My statement above might be wrong if the instrument cluster does not activate.

Yes, when I sent 12v to either of fuse F13s the display powered up and displayed the usual stuff except for the total mileage (odometer).

[admiral51]

Did you get the beeping from the steering column area when you powered up the fuses ?

Colin

[napping]

Did you get the beeping from the steering column area when you powered up the fuses ?

Colin

No beep when powering up the fuses from a live 12v fuse, as I had already connected the battery. I only get the beep when first connecting the battery.

[ozvtr]

I think this is the thing you mean? If so they are just as helpful as the specific circuit diagram. Just shows most of the connections going to an 'electronic box'.

Yes.
Thanks, I thought as much.

[ozvtr]

I mean no malice or disrespect to anyone with the following comments. I hope no one takes them that way.

While all this "f13" business is very interesting and amusing, I don't see it getting your C2 back on the road.

Supplying power to the BSM powered it up and it started doing stuff, and we discovered that the BSM does feed power back to the BSI. But we were never concerned about the BSM in the first place. Again, all very interesting but as I see it not quite relevant.

And you have demonstrated that applying power to pin 1 of the 16pin green connector "stimulates" R7 into closing and some car components "came to life" by having power applied to them.

I contend that applying power to pin 1 of the green connector is tantamount to a "reflex action" of a dead animal!

Again I say that I have not seen anything to show me that the BSI is communicating with any other ECU when you have applied power via any of the F13 fuses. The fact that you could not control any of the BSM functions is evidence to me of that.

Actually, Wheeler's picture of the BSI might throw a spanner in the works!! If you are looking for something to stop the BSI from waking up, there are 3 connectors with virtually nothing but input/outputs!!! There is a 40 pin blue, a 40 pin white and a 40 pin black connector. Now some of these may not be used and some might not be fully populated but they are all potential suspects!!! How many are used on the car?

It just became way harder than I thought. If you are looking for a power supply problem I am sure we have exhausted all avenues there. If you are looking for an external input preventing the BSI from waking up (or working)...well...I don't know where to start!

If we discount a power supply issue. We are still back to the snag of determining if the problem is internal or external to the BSI. How do we do that?

Go through pin-by-pin looking for an erroneous short to ground/short to positive? Need to go through each circuit diagram to find out where each of the pins go and determine what the findings should be. Laborious, some results might be indeterminate with out more data. Not very practical? I have done point-to-point continuity checks on the F111 APQ-171 Terrain Following Radar (TFR) racks. So this would be a piece of cake!

Swap BSI. Run the risk of blowing up "new" BSI (slight IMHO). Need to obtain BSI ($).

Put current BSI in working car. Risk damaging car (slight IMHO).

Send BSI off for testing. Risk fault is external to BSI and pay $ for nothing.

Sorry, just being pragmatic.

I am sure others might come up with other options but I am running out of ideas.