Very strange car fault - Citroen C2 - fuse box? BSI? BSM? Please help

[agi1190]

Hello everyone.

I'm getting a bit desperate, as my car has been at mechanics 3 times already and nothing really helped.
Here is the problem:
My 2009 Citroen C2 has an electrical/electronic fault which no one can find so far. The car sometimes starts with no issues whatsoever, and sometimes almost nothing will work - central locking is not working, when the key is turned in the ignition, there is a number of faults displayed: "braking system faulty, airbag system faulty etc." and turning the key in 3rd position (to start the engine) does nothing - not even a click of the starter motor.
And then a few days later - out of nowhere, It might wish to start again with no problems at all. And once it was running, let's say to go to the shop, once done with the shopping it won't start again.
Last week a car electrician replaced the fuse box and the car worked for a couple of days and then the problem came back again. Had my car towed twice, it cost me a lot of money already to recover and diagnose the issue, which couldn't be found (some errors displayed, but nothing specific to help the mechanic to find out). Some suspect a faulty BSI unit, which would need to be repaired, however, the car electrician says if that was the case, the fault would be constant. He suspected faulty/damaged wiring or a fuse box - which he then replaced. All professionals said that there is no visible water damage to the system, so this shouldn't be the problem.
Also, there is a strange noise coming out of the stepper motor while the car is faulty, I'll try to attach the short video with it.

Please help, I am really desperate, only had this car for a few months and if I even to try to sell this car I need to get it running...

I would really appreciate any help or ideas you guys might have. I know it's a bit vague, but this is the only information I have as I am not a professional.

 

[DPG]

Got all the hallmarks of either a broken wire either at a connector or in the loom, or maybe the loom has rubbed against bodywork somewhere and is shorting. Cod be tricky to track down without knowing which of the many signals the problem is with.

I had a problem with my Sierra once many years ago where the fuel pump relay kept going faulty. Went to garage twice, supposedly fixed. Several days later each time same thing happened, either relationship or fuse went. Turned out to be the harness rubbing on the inside cavity of the car bodywork near where the tailgate closes. Took me nearly all day to sort that if you include taking loads of trim off, driver's seat out, etc. I connected a meter between the wire that I had determined had the problem and ground. Did a wiggle test on the loom from front to rear of car what checking meter. Obviously I started at the front and the fault was actually at the back!!!

 

[agi1190]

Much appreciated! Definitely will need some extensive (and expensive) investigation from the mechanic. Wish I had some knowledge on that, maybe could determine what's the fault myself, or have my dad nearby who's an electrician and could at least have a look, but he's a thousand miles away.
If anyone has any more ideas, feel free to comment.
Some say that the BSI fault could come and go, however, in my opinion (a gut feeling) it's some sort of connector or a wiring problem. The mechanic who connected the car to the diagnostic system could not determine what is wrong, and he said when the car was faulty, he couldn't even get a response from the system.
It's strange, as it was happening over a longer period of time - at the start, a few months ago, when I drove somewhere and went away from the car for a while (i.e. shop or whatever) and returned to the car, then it would display the problem, however after waiting a few minutes and locking/unlocking the car with the remote (even though it wouldn't work) helped. And then one day I just got stuck and had to be recovered from a car park in the middle of the city.

The lesson for me - french cars really are illogical and prone to electrical faults... Cheap to buy, expensive to maintain.

 

[ruston]

It could be the connections on the base of the ignition switch worn out and flying in loose formation. I had a similar problem once. The contacts were making multiple contact or no contacts at all.
You may be lucky if it is that and the base is removable from the barrel and can be replaced.
How does the key feel when you are turning it?

 

[Ziggie]

perhaps you should try a test like a
Parasitic loss and test by removing each fuse in turn and see if the problem goes away and things spring into life.One circuit might be short circuiting (temperature related or vibration) and performing the test when the car is “dead” may provide some info.

Then again this might be a stupid idea.

 

[agi1190]

The thing is, I thought that the car was not starting after it was driven for a while, so when trying to start it again while still hot, then could possibly cause some connection issue. However, yesterday the car failed to start when cold (It was run the previous day and left overnight, and couldn't start it in the morning again). Will pass on your ideas to the mechanic, although I think this is going to be a long process

 

[agi1190]

It could be the connections on the base of the ignition switch worn out and flying in loose formation. I had a similar problem once. The contacts were making multiple contact or no contacts at all.
You may be lucky if it is that and the base is removable from the barrel and can be replaced.
How does the key feel when you are turning it?

Key seems to be working ok in the ignition, quite smooth and no noises, I don't think there is any difference in turning in ignition whether the car starts or not. Just not cranking when the faults are displayed...

 

[Ziggie]

The thing is, I thought that the car was not starting after it was driven for a while, so when trying to start it again while still hot, then could possibly cause some connection issue. However, yesterday the car failed to start when cold (It was run the previous day and left overnight, and couldn't start it in the morning again). Will pass on your ideas to the mechanic, although I think this is going to be a long process

This won’t work if the fault is from the battery to the fuse box. Obviously another check is to check that the voltage entering the fuse box is correct. If you don’t have voltage there. Then check the voltage to the ignition switch . Perhaps quicker to check at the starter motor.

 

[agi1190]

Would the ignition switch have an effect on the central locking system? Currently, the car is not starting, but the central locking is not working either, except for the boot - I can lock and unlock the boot for some reason. When the car does wish to start (sometimes), the central locking works fine, along with everything else.

 

[DPG]

Wonder if damp has got into a connector or module somewhere. Your best bet for this would be joining a citroen forum. See if there are any known issues. Jag XFs have a known problem where the windscreen washer pump leaks and the water tracks down to the main control unit. Can cause all sorts of issues. Mine ended up with one sidelight stuck on and the aircon doing strange stuff.

 

[agi1190]

Haha speaking of which, I tried to register to a Citroen forum, but they seem to be having a server error, how ironic...

 

[Ziggie]

Would the ignition switch have an effect on the central locking system? Currently, the car is not starting, but the central locking is not working either, except for the boot - I can lock and unlock the boot for some reason. When the car does wish to start (sometimes), the central locking works fine, along with everything else.

Good point - but if there is a short circuit on any circuit, the voltage drop might be sufficient for things not working while others using very little current might work.

Can you clarify the boot locking? Is it the central locking working for the boot or are you pressing a different button to lock the boot. I can lock and unlock my boot using a separate button on my remote.

 

[Ziggie]

Part of parasitic loss is to measure the current being used (preferably using a clamp meter) .

so a good question is “ what current is being drawn from the battery “ when not working.
If there is a high current being used, then you have a short somewhere.

 

[agi1190]

The buttons on the remote control work only with the boot, the rest of the car cannot be locked/unlocked that way. To open the door I need to manually unlock with the key at the driver's door, but the central locking still won't work that way (passenger door stays locked, until I open with a handle from the inside). The button on the dash to lock all doors from the inside (citroens have them) will not work when the car is faulty.

 

[Ziggie]

Given the extent of the problem, I guess the one should concentrate on the common area - battery , battery clamps, fuse box entry ( several fuseboxes?) .I
I had a car stopped instantly , nothing working . Problem was a connection at a bolt. (I can’t remember if it was live or a connection to the bodywork of the car.)

might be that the boot has a separate connection to the bodywork!