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

[ozvtr]

Not nowadays. But I can use one. I do still have a very old but precise mirrored Megger which, if used properly, is very good in cases like this.

An old Megger or AVO?

NB. If the consensus is the BSI is at fault, I can send it away for testing.

As you can see this is a rare and bizarre fault that you have here. One that, apparently, a lot of people have not seen before. The BSIs tend to be reliable and most of the common faults have been sorted by now. So on one hand we are curious to solve it but on the other, we don't want you to waste your time or money sending the BSI off if it's serviceable.
I have been a technician for a very long time and I can tell you that nothing is guaranteed until the thing you are working on is fully functional. You can be dead certain about a diagnosis...replace the component...but the thing still doesn't ^%$#ing well work!
The first rule to fixing something is to understand how it works in the first place. As you can see we are floundering a bit here. There is the way you assume something works and then the way it actually works. I can't speak for any one else here but I didn't attend the PSA technician's course. So you will have to take what I say on face value.

Does the BSI repair company have fixed prices? One for testing, one for repair. Or a variable price based on the time to repair?

Have you checked out the price of a cheap BSI from Ebay or the breakers? Or are they just not cheap? (I don't live in the UK)

[ozvtr]

Have you checked out the price of a cheap BSI from Ebay or the breakers? Or are they just not cheap? (I don't live in the UK)

Yes...I know the engine wont run, key fob wont unlock the car, the radio will beep, blah, blah, blah but otherwise the car should come to life!

[xantia_v6]

My opinion is that the CAN bus is a red herring here. The BSI should be woken up by opening a door, or operating the key fob, neither of which require the CAN bus. I think that the fault is one of (in order of likelyhood):

* A broken power feed wire in one of the harnesses
* Corrosion in a connector
* A failed relay in the BSI
* Another fault in the BSI

If any of the first 3 are the cause of this problem, then a jumper bypass to the affected circuit will restore normal operation, and reduce the size of the haystack.

[dan g]

Does this model have the piggyback fuse busbar setup on top of the battery like a c4.
If so is the circuit breaker toward the front switching ok.

[Dormouse]

Not nowadays. But I can use one. I do still have a very old but precise mirrored Megger which, if used properly, is very good in cases like this.

An old Megger or AVO?

NB. If the consensus is the BSI is at fault, I can send it away for testing.

As you can see this is a rare and bizarre fault that you have here. One that, apparently, a lot of people have not seen before. The BSIs tend to be reliable and most of the common faults have been sorted by now. So on one hand we are curious to solve it but on the other, we don't want you to waste your time or money sending the BSI off if it's serviceable.
I have been a technician for a very long time and I can tell you that nothing is guaranteed until the thing you are working on is fully functional. You can be dead certain about a diagnosis...replace the component...but the thing still doesn't ^%$#ing well work!
The first rule to fixing something is to understand how it works in the first place. As you can see we are floundering a bit here. There is the way you assume something works and then the way it actually works. I can't speak for any one else here but I didn't attend the PSA technician's course. So you will have to take what I say on face value.

Does the BSI repair company have fixed prices? One for testing, one for repair. Or a variable price based on the time to repair?

Have you checked out the price of a cheap BSI from Ebay or the breakers? Or are they just not cheap? (I don't live in the UK)

Avometer Mk 8 in a leather case.

When I first entered into Vehicle Diagnostics I had to remember 3 simple rules - Air, Spark and Fuel. Dead easy with SU carbs and pumps with Lucas points and coils. Then along came Lucas mechanical injection, then Bosch and Magnetti ecus, anti theft devices and remote entry fobs. Then the CanBus and on to where we are today where everything is microprocessor controlled - even your toaster in the kitchen!
The 3 simple rules still apply - you just have more "bits" (and bytes) that have to be right before you can proceed. I am glad I am still not in the game trying to work on this one professionally. Don't get me wrong, I still look after my own cars (knackered knees, hips, arthritis and gout allowing) but the perennial problem is getting any kind of meaningful information from the manufacturers to allow diagnosis. Yes, we get fault codes to read but they do NOT tell you what the fault actually IS, only what it is affecting. For most practical people, they can handle dismantling and repairing, a bit of soldering and circuit tracing but they never signed up for computer networking. Most people don't even understand why a light bulb has to be CanBus suitable. So, with this in mind and with Napping's perseverance and patience, lets get a step by step process going and save Napping's wallet and sanity.

[napping]

OK the easiest way to check the CAN lines is checking the resistance across pins 7 & 14 of the diagnostic socket, you should get 60 ohms (give or take a couple of ohms).
You can check the voltage of the CAN high & low here too. Measure the voltage between pin 7 & earth then pin 14 & earth. You should get 2.5 V on each however I suspect you may not get this as we suspect the BSI has not woken.

Just tried to check the CAN resistance and found that Pin 7 is not used (there is no wire behind it). Pin 14 is present but the voltage is zero.
I still have 12.8v to F17 though (the heated rear screen!?!).

[napping]

And OBD pin 16 (battery power) has 0.13v.

[Dormouse]

Try the pins in this diagram

F1 is starting so I will be AWOL for a while

[napping]

Does this model have the piggyback fuse busbar setup on top of the battery like a c4.
If so is the circuit breaker toward the front switching ok.

The battery just has the standard +ve and -ve clamps.

[napping]

F1 is starting so I will be AWOL for a while

You, me and many more

[dan g]

Pin 6 can high

Pin 14 can low

[wheeler]

Sorry, my bad, that was a typo (well the 7 is right next to the 6 on the key board )
I've obviously then copied it for the rest of the post when referring back to it
Here is the diagram of the OBD socket specific to a Full CAN C2.
Some options may not be present.
I suspect you wont have the ignition controlled live at pin 1 as this is provided by the BSI.

[wheeler]

My opinion is that the CAN bus is a red herring here. The BSI should be woken up by opening a door, or operating the key fob, neither of which require the CAN bus. I think that the fault is one of (in order of likelyhood):

It may be but has to be ruled out before condemning the BSI. Remember the BSI may be getting the wake up request but if there is an issue with the CAN circuit then all the other ECU's wont know the BSI has woken up like the injection ECU, BSM instrument panel etc.

As for no CAN voltage at the pin 14 you already checked like i said in the previous post im not expecting to see that in this case but even if nothing is transmitting on the CAN you should still get 60 ohms regardless. If you get 120 ohms there is a break in the CAN lines.

This is a very frustrating fault when you cant be there hands on. It has to be confirmed that the BSI has all its power supplies & earths and also that the CAN lines are ok.

[napping]

As for no CAN voltage at the pin 14 you already checked like i said in the previous post im not expecting to see that in this case but even if nothing is transmitting on the CAN you should still get 60 ohms regardless. If you get 120 ohms there is a break in the CAN lines.

CAN resistance between Pins 6 and 14 is 62 ohms. Both pin 6 and 14 have zero voltage.

[Dormouse]

Is this voltage tested between pins 5 & 6 and 5 & 14?