C5 electrical issues (poss bcm?)

[rob78]

Evening folks just been stung buying a 2002 C5 2.0 Hdi SX, spent two days working on it and the final straw has just come when I had to phone the missus to come and let me out as I was locked in so if possible I would appreciate some help as i have tried the obvious stuff.

the fuel flap was stuck shut as the pin was locked across, Ive cheated and undone the lock nut and popped the pin backwards so managed to release the flap and put some diesel in

The rear doors are stuck shut had the door cards off to get to the childlocks as per the common fault and released them but they are still jammed shut, pulling on the door rods will not open them.

The boot unlocks and locks fine with the central locking but the front doors are another matter.

Both fronts lock and unlock with the key and can be accessed from the outside (thank you WD40) but if you lock the door when inside with the panic button you cannot get the doors to open from the inside and have to open the drivers window and insert the key in from outside and turn it. Had the door cards off both front and checked for movement and lubricated the moving parts. In fact, if you lock the doors with the fob from the inside you cannot open the door from within.

Passengers front door wont open from the inside at all

Pressing unlock on the fob makes the indicators flash on and off rapidly between ten and twenty times, you can hear the locking engaging and it seems to lock OK but when you press unlock you get a click from the doors but they don't unlock, you have to open with the key again.

I have tried to reset the BCM module three or four times but it seems no better, I cant get Lexia / diagbox to read the ECU nor can i get a standard OBD reader to work. The car starts, runs and drives spot on with no warning lights.

I'm thinking maybe the BCM is shot and needs to be replaced but before I start pulling the dash apart id be hugely grateful if someone with more knowledge could point me in the right direction as I had a bad experience with a renault last year that i spent £800 on that I still ended up scrapping the whole point of getting this C5 was as a family motor as its not practical shoving two stroppy teenagers in the rear of my missus's 206 so the fact the back doors are stuck shut adds insult to injury

[wurlycorner]

Argh, sorry to hear of your agro.

I very much doubt it's anything mechanical with the locks, given it affects so many doors... The symptoms sound like it's deadlocking?

Are you sure you've followed the correct full BSI reset procedure? (no doubt someone on here can point you at the definitive c5 one).

Also I wonder if it's a replacement remote key and it hasn't been properly paired with the car???

[Stickyfinger]

and no mention of a new battery...or a 24hr charged one.

NEVER do such work on a C5 without first charging a known 100% battery

[myglaren]

Reset/Battery replacement.
That's a whole plethora of problems you seem to have inherited there Rob. Hope we can help fix them.

Welcome to the FCF

[Stempy]

You are in the right place to get your C5 fixed up. Just sorted mine with the help and advice from the good folk here. It does sound a bit like you've got BSI related issues, they are very easily upset by poor batteries and jump starting etc. If you do find the BSI is at fault and unrecoverable you could send it to BBA Reman who will repair it for you, they did mine for £160 inc VAT and shipping.

[rob78]

thanks for replies guys!

sorry I forgot to mention i took the battery off and charged it manually on a recon cycle overnight as my first thoughts were was there enough juice to turn the locks over its a varta and I have recipts saying its only six months old, had a multimeter on it and its putting out what it should do

if only that had been the cause it would have been simple, but as ive found out with my previous 4 french cars it never is when its electrics!

the resets ive tried had slightly different times to the ones in your post but im just running through the steps in the post above be nice if this sorts it out before i spend £160 being a poor electrical engineering student

on the plus side, if theres some obvious damage to the BCM then I might be able to get one of the lecturers at college to have a look at it as they do the SMD stuff

***** QUICK UPDATE *****

After following the procedure, both fronts lock with fob but don't unlock. The left and right reading lights work now but the rest of the doors are as they were. Both fronts can be locked with key from drivers door but unlocking with key only unlocks the door that has the key inserted in it

Ive worked through the Citroen dealer BCM fault diagnostic chart and could get all the way to step 13 (change BCM module) would be easier if diagbox would play ball ive reinstalled it twice but it still wont read the C5 but its fine on my 206.

[GiveMeABreak]

"Ive worked through the Citroen dealer BCM fault diagnostic chart and could get all the way to step 13 (change BCM module) would be easier if diagbox would play ball ive reinstalled it twice but it still wont read the C5 but its fine on my 206".
Re your Diagbox - The C5 and some 308s can't be read with some older versions of the hardware - a firmware update may solve this - BUT it also depends on whether your reader has all the required chips and resistors too - check out the lexia / diagbox thread for more on this.
As you have multiple issues - you really need to get the lexia talking to it - so if your kit isn't upgradable, check out the C5 members with Lexias - there may be someone near you that can help.

Just as an aside - the 'deadlocking' function is designed to prevent opening of the doors from the inside, but this is usually only activated from the key fob after the second press.
Re the rear doors: you've said you've had the door cards off, but have you checked the status of the manual child locking (somewhere near the door latch there should be a round plug (maybe yellow from memory) that you are supposed to slot your key in and make a quarter or half turn to enable or disable the child locking)?

Really need to get a compatible lexia on there, run a test, clear all the faults and re-run the global test and then see what the score is.

[wheeler]

Just as an aside - the 'deadlocking' function is designed to prevent opening of the doors from the inside, but this is usually only activated from the key fob after the second press.

I'm pretty sure on a mk 1 C5 the remote always deadlocks the car no matter how many presses on the button, is you can't not deadlock it with the remote. the only way to not deadlock it is to use the key in the lock barrel. You have to just lock it with the key & quickly remove the key again as if you hold the key in the lock position for more than a second or two or do a second locking action in quick succession the car will also deadlock.

[Stempy]

Just as an aside - the 'deadlocking' function is designed to prevent opening of the doors from the inside, but this is usually only activated from the key fob after the second press.

I'm pretty sure on a mk 1 C5 the remote always deadlocks the car no matter how many presses on the button, is you can't not deadlock it with the remote. the only way to not deadlock it is to use the key in the lock barrel. You have to just lock it with the key & quickly remove the key again as if you hold the key in the lock position for more than a second or two or do a second locking action in quick succession the car will also deadlock.

That is certainly the case on mine, it has one press deadlocking. This can be turned off with the Lexia to simple locking.

[rob78]

thanks again for the replies guys

as far as releasing the child locks on the back door, Ive managed to get behind the block where the child lock shaft and turn the clip towards the car body following the online tutorials.

I will work through the lexia stuff again today and see if we can get it running, however im wondering if theres an issue with the obd port as not even a standard obd reader is recognising the ecu

[wurlycorner]

Where abouts are you?
If there's someone nearby with a known working Lexia setup, that may well be the best thing to try at the moment.

[GiveMeABreak]

I'm pretty sure on a mk 1 C5 the remote always deadlocks the car no matter how many presses on the button, is you can't not deadlock it with the remote. the only way to not deadlock it is to use the key in the lock barrel.

Chaps, I think you'll find deadlocking is an option (for safety) and is manually activated
I've just looked up the C5 MK1 in the documentation and there are definately 3 distinct functions for the plip shown: Under connections, There is 'Locking request', 'Deadlocking Request' and 'Unlocking Request'.
Having said this, there are parameters that need to be configured 'Type of locking - No Locking, Deadlocking, Single Locking. The following parameters can be read with the Lexia:
'Vehicle Locking Status': Initialised, Unlocked, Locked, Unlocked (Driver only), Deadlocked, Unstable. There is also a separate Lock Deadlocking Relay that can be read.

So I can't see why there would be mention of deadlocking as a separate state if it was on all the time, i.e. the default. The whole locking function is covered under After Sales Operations, under door management. Regarding the actual remote plip - somebody would have to clarify whether changing the locking parameters would then alter the plip locking function / sequence.

[Stempy]

If I lock mine with the plip, if there's someone inside they ain't getting out. The lock button on the dash just locks the outer handles as does a key in the door. No doubt this will vary from spec to spec.

[Stickyfinger]

IF you are crossing the bridge you are welcome to pop in and use my Lexia...I know it works with all the C5 styles (just wish it did with the Activa )

[GiveMeABreak]

If I lock mine with the plip, if there's someone inside they ain't getting out.

That's what the deadlocking does - so if they break in your car through he windows, they can't open the doors

The lock button on the dash just locks the outer handles as does a key in the door.

Great idea - so the wife's handbag won't get hijacked off the front seat at the traffic lights!

No doubt this will vary from spec to spec

Well mine had this feature (and the auto window closing) on a '51 SX