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

[static zap]

My first step would be with a cheap voltmeter ,to check nothing strange going on with battery volts and a lightly used car.
..can also look for volts on things earthed -allegedly- ..

 

[ruston]

Have you checked the MOT history to see what any past failures were. Has it it suffered any collision damage or advisories on corrosion observations. Some failures may give you a clue to a progressive fault.

 

[stanwelbach]

Could be a number of things which I will expand on later but first can I ask that when the car is faulty, do the headlights work at full brightness? If so this rules out a bad battery and parasitic draw (as the battery would go flat on a regular basis)
Is the starter motor and its circuit in working order(has this been confirmed by the auto electrician)?
Please report back for part 2.
.

 

[agi1190]

The car decided to start today after 3 days(!), took it straight to the mechanic. Told him some of your ideas guys, it might take days to get it sorted though. I will keep you updated.
After turning the car off, the fault came back on soon as it was locked, so mechanic saw it as well. We'll see, fingers crossed. Soon as this is sorted I'm probably going to sell it as I honestly can't trust this machine anymore.

 

[agi1190]

Could be a number of things which I will expand on later but first can I ask that when the car is faulty, do the headlights work at full brightness? If so this rules out a bad battery and parasitic draw (as the battery would go flat on a regular basis)
Is the starter motor and its circuit in working order(has this been confirmed by the auto electrician)?
Please report back for part 2.
.

When the car is faulty, there are no lights whatsoever, it's not a battery or alternator, had that checked already.

 

[DPG]

The car decided to start today after 3 days(!), took it straight to the mechanic. Told him some of your ideas guys, it might take days to get it sorted though. I will keep you updated.
After turning the car off, the fault came back on soon as it was locked, so mechanic saw it as well. We'll see, fingers crossed. Soon as this is sorted I'm probably going to sell it as I honestly can't trust this machine anymore.

Tell whoever buys it though. Don't drop the problem on to someone else.

 

[agi1190]

I'm aiming to fix the problem, which probably will cost a bit, then probably part exchange for another vehicle.

 

[stanwelbach]

When the car is faulty, there are no lights whatsoever, it's not a battery or alternator, had that checked already.

Get your mechanic/auto electrician to check the fusible link that's attached to the +ve terminal, these can become oxidized over time.

 

[ray2frost@btin]

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

Which fuse box was replaced? check middle plug in under bonnet fuse box(pics attached

 

[agi1190]

Car is at mechanics now, can't check it myself at the moment. I hope he'll find out what's wrong in there.
The fuse box he replaced before was the engine bay one, which did not help in the end.

 

[stanwelbach]

If it was with me I'd be checking:
Powers and grounds (Battery, starter relay, solenoid, starter motor etc, ect.)
Scan for codes, (dtc's) and perform a health check) check to see if all modules are communicating with each other.
Check CanBus resistance (should be approx. 60 ohms across pins 6 and 14 on DLC or at any control module)
Check CanBus signal and voltages, CanH and CanL with a scope.
Throttle body acuator and sensor (power and ground)

 

[DPG]

If it was with me I'd be checking:
Powers and grounds (Battery, starter relay, solenoid, starter motor etc, ect.)
Scan for codes, (dtc's) and perform a health check) check to see if all modules are communicating with each other.
Check CanBus resistance (should be approx. 60 ohms across pins 6 and 14 on DLC or at any control module)
Check CanBus signal and voltages, CanH and CanL with a scope.
Throttle body acuator and sensor (power and ground)

Must admit I'm assuming they have already checked for current or historic fat codes, but we don't know.

OP - is the garage experienced with this sort of fault finding?

 

[stanwelbach]

Must admit I'm assuming they have already checked for current or historic fat codes, but we don't know.

OP - is the garage experienced with this sort of fault finding?

You never know, not all mechanics can fault find, a lot just throw parts at it in the hope it fixes it.

 

[agi1190]

I've never used the services of this car electrician before, didn't really need it to be honest. After the first failed repair attempt, my "usual" mechanic wanted to send the BSI module away for repairs (around £200+) which is not a guarantee to fix this problem. The car electrician guy I left my car with today seems fairly genuine. He did diagnostics of the car free of charge, found the fuse box second-hand online (as he was not certain whether it would help or not, diagnostics were not clear, and apparently, there are no faults shown when the car is running, on the other side, when it's faulty he could not get a response from the system) and charged me only for the part and an hour of labour.

My "usual" mechanic charged me £70 for diagnostics and fiddling with the cables (he literally said that), which resulted in my car starting, but then the fault came back the very same day. And they were very blunt in saying that they have no idea what's wrong and it will probably cost hundreds to get it sorted. I got also a feeling that they could not be bothered with this either, rather focus on people's clutches or brakes, hence throwing the large bills in the conversation to put me off.

 

[Ziggie]

One of the techniques for finding problems is to disturb the cables. This checks for poor connections . Given you documented this above , it becomes likely that there is a bad connection either in the positive or negative wiring . It is also possible that this is temperature related.

in older times, I had a car that would start and fail when driven a few feet. Wait 5 minutes and it started again. Fault was a loose connection which broke with the vibration and settled back when stationary.

let’s hope it’s a bad connection and it fixes very easily. Tampering with the wires is a recognised technical method

 

[DPG]

One of the techniques for finding problems is to disturb the cables. This checks for poor connections . Given you documented this above , it becomes likely that there is a bad connection either in the positive or negative wiring . It is also possible that this is temperature related.

in older times, I had a car that would start and fail when driven a few feet. Wait 5 minutes and it started again. Fault was a loose connection which broke with the vibration and settled back when stationary.

let’s hope it’s a bad connection and it fixes very easily. Tampering with the wires is a recognised technical method

'Wiggle test'

 

[stanwelbach]

Car is at mechanics now, can't check it myself at the moment. I hope he'll find out what's wrong in there.
The fuse box he replaced before was the engine bay one, which did not help in the end.

Did you manage to get it sorted?

 

[agi1190]

The car still at mechanics, the guy can't find the problem, says the car is starting every day, but obviously not fixed the problem, so I don't think anything will be done about it.

 

[Ziggie]

The car still at mechanics, the guy can't find the problem, says the car is starting every day, but obviously not fixed the problem, so I don't think anything will be done about it.

Probably need to drive it as this will cause vibrations. The problem also could be temperature related. This would show if the car heated up ( may de dependent on your weather forecast

 

[agi1190]

Probably need to drive it as this will cause vibrations. The problem also could be temperature related. This would show if the car heated up ( may de dependent on your weather forecast

I'm not sure as some days car would start no problem after standing all night on the drive, and then the next morning it would bring up the fault again and not start... I'm lost and really fed up, I feel like just selling it to we buy any car and get £500 or whatever. No one seems to have an idea what to do with this without stripping the whole car, which might not even show the fault.

 

[DPG]

Sadly this sort of fault can be incredibly difficult to find, even by decent diagnostic places.

Someone I knew a few years ago had a Vauxhall Astra which started having electrical problems from when it was nearly new. After many trips to the dealers, and much work having been done (including replacing a lot of the wiring), they scrapped it and supplied an alternative car.

I do hope you can get it sorted though. It's one of those where at some point you may have to cut you losses though.

 

[agi1190]

So - I have my car back, nothing fixed. The mechanic said that car was starting every day when it was round his garage, and he said there isn't much he can do without going to Citroen for proper scanning and fault finding, which they charge a fortune for, not worth for such an old (and cheap) car. Probably going to sell it for parts, which will see me end up with £400 for it (tops), while in April I've paid for the vehicle £1700. Either I've been terribly unlucky with the car or the fault was masked by the seller back in April, I'm glad to see it go as I honestly hate it now.

 

[agi1190]

At least the mechanic didn't charge me anything as he couldn't fix it over the last week.

 

[DPG]

Yes it seems like it's time to cut your losses I think.

 

[ruston]

The auto electrician is correct about the codes. There are some codes that only the manufactures and approved dealers have access to. It is expensive to have them scanned.
Just maybe to take the sting out of it a bit, I doubt that the seller would of been able to mask that fault if a trained auto electrician could not find it.