54 C3 1.4HDI non-start FIXED

[MikeT]

This is a continuation from this thread viewtopic.php?f=3&t=60625 as the car's now changed ownership

As previously reported, with the ignition on the sidelights come on. I noticed the engine diagnostic light also stays permanently lit. The engine will crank but not start.

Plugged in Diagbox but fell at the first hurdle - the RPO. There's no label in the drivers door shut like on the C5 and nothing obvious in the engine bay either - as the other doors don't open, I couldn't check their shuts. So took a wild guess and entered 09000 which I now know is several years too early but still, at least I got some dialogue which is a good start.

I then decided to try a BSI reset but when it came to turning the sidelights on, they wouldn't. Then the heavens opened up and I came in for a nice cuppa char.

[GiveMeABreak]

Mike, the RPO is 10046 - I still have the VIN from earlier.

That smacks of the BSI - there is no dialogue with the control module under the steering wheel which we know communicates directly with the BSI - and we know the radio already has issues as that is controlled by the Multi Function Display - for which there is also a fault and ditto with the injection.

If the BSI is playing bananas, it may not be shaking hands with the engine ECU and therefore not allowing it to start. I know one of the backup modes results in the sidelights being turned on - but can't remember now OTTOMH.

The BSI at least seems to be communicating with Lexia, so I'm wondering if the VAN network wiring has been wrongly connected. I would certainly check out the wiring at the back of the radio - make sure nothing has been wrongly connected or spliced in. If the VAN wires have been spliced with other wiring or connected to non compatible kit, then this can affect the data being sent to the other systems on the network.

[wheeler]

I know one of the backup modes results in the sidelights being turned on - but can't remember now OTTOMH.

The sidelights come on as a backup mode when the BSI cant communicate with the com2000.

I would leave the radio completely disconnected for the time being.
Does the horn work out of curiosity ?
on the 6 way grey connector on the com2000 do you have an earth & a permanent live supply ? You should also have a VAN+ 12v supply that is powered up when the network is awake.

[MikeT]

Thanks for the correct RPO Marc.
Now, where's my radio removal tool....

Didn't try the horn but I can't get lights, indicators or wipers to work, wheeler.
No idea on the com2000 supplies at this point, where do I find the connectors - behind the steering cowling I guess?

[MikeT]

Is this relevant at this stage?
The INSTRUMENT PANEL fault reads "No Communication on the DATAB Wire"

[wheeler]

remove the steering column cowlings, there is a 6 pin grey connector going in the back of the unit.
Do you have access to an oscilloscope by any chance? this is what you really need to check the DATA & DATAB wires properly.

[MikeT]

No to the scope I'm afraid.

[GiveMeABreak]

I know one of the backup modes results in the sidelights being turned on - but can't remember now OTTOMH.

The sidelights come on as a backup mode when the BSI cant communicate with the com2000.

That's the one!
I can get you a wiring diagram for the Comms Unit to BSI if that's any help - but there's obviously a communication problem on the VAN wiring - it's just trying to locate it - but I suspect it will be localised between the BSI in the glove box and through the dash via the radio wiring on the way to the Comms unit. Just about everything concerned that he's had an issue with (Immobiliser, Locking, Lights, Radio, MFD etc.) are linked to the Comms unit and BSI.

That's another reason why I suggested you check the wiring around the rear of the radio connectors - as it would appear the faults happened after changing the aftermarket radio and the OEM one back and forth.... If the VAN wires have been spliced it would explain a lot of the issues.

[xantia_v6]

I have locked the previous topics on this car to prevent confusion.

[EDC5]

Am I right in thinking that the side lights are controlled from a Solid State Relay from within the BSI itself on the C3 ?

If theyre not working, perhaps it has shorted out and damaged the PCB of the BSI ?

[GiveMeABreak]

It's a backup mode - they do work - but when there are certain comms issues the Module under the steering wheel commands these to come on. That module is in charge of quite a lot actually.

[EDC5]

I see, it's a signal that the car is in a state of electrical distress then?

[wheeler]

I know one of the backup modes results in the sidelights being turned on - but can't remember now OTTOMH.

The sidelights come on as a backup mode when the BSI cant communicate with the com2000.

That's the one!
I can get you a wiring diagram for the Comms Unit to BSI if that's any help - but there's obviously a communication problem on the VAN wiring - it's just trying to locate it - but I suspect it will be localised between the BSI in the glove box and through the dash via the radio wiring on the way to the Comms unit. Just about everything concerned that he's had an issue with (Immobiliser, Locking, Lights, Radio, MFD etc.) are linked to the Comms unit and BSI.

A wiring diagram would be really helpful here.
I would be concentrating first on Body VAN 1 here, this has under bonnet fuse box(BSM), airbag ECU & com2000 on it.
The radio, MFD & instrument panel are on the comfort VAN. Each of the 4 networks are all connected together via the BSI. First step though is checking for power supplies & earth to the com2000 unit. If the supplies are ok next is to check the VAN wires for continuity, short to earth or shorted to each other. This is a lot easier than it might sound when you have the correct wiring diagram.

[GiveMeABreak]

I see, it's a signal that the car is in a state of electrical distress then?

There are lot of backup modes each signifying something different - but in this case there is not one particular fault - but several that are symptomatic of the network being up the swanny as there are so many systems affected and doing the wrong things - like the child lock activation button locking the doors.. It will be interesting to see if this one can be saved though.

[GiveMeABreak]

It looks like I will have to put the wiring up in mini parts as there is no overall one for the Comms unit, but I should be able to get up the smaller sections relevant to the lighting and other controls - so we should be able to see the common areas. I will do this tomorrow, but in the interim, here's an extract from the BSI going into Backup Mode

1. Vehicle exterior lighting
1.1. BSI diagnostics
The sidelamp, dipped beam and main beam positions are mutually exclusive . If it receives more than one position present from the lighting control, the BSI changes to back-up mode: It switches on the dipped beams via the engine relay unit and forces the sidelamps to switch on. As soon as the fault disappears, the BSI changes back to nominal mode and updates the system status.

1.2. Diagnosis of switch module under the steering wheel
The switch module under the steering wheel detects faults relating to buttons jamming on the one-touch foglamp controls . An electronic malfunction entails a loss of communication between the switch module under the steering wheel and the BSI.
Loss of communication between the BSI and the switch module under the steering wheel, or sending of invalid values :

• If the vehicle has the automatic lighting of headlamps option, the BSI activates the automatic headlamps mode.
• If the vehicle is not equipped with the automatic headlamp lighting option, except with ignition on, the BSI commands the engine relay unit to switch off dipped beams, main beams and front foglamps . The BSI forces the switching off of the sidelamps and rear foglamps. With ignition on but engine not running, the BSI commands the engine relay unit to switch off dipped beams, main beams and front foglamps. The BSI forces the switching off of the rear foglamps and the lighting of the sidelamps. With ignition on and engine running, the BSI commands the engine relay unit to switch on the dipped beams and switch off main beams and front foglamps. The BSI forces the lighting of the sidelamps and the switching off of the rear foglamps

On re-establishment of communication or on sending of valid values, the BSI exits from the back-up mode described above . The BSI commands the engine relay unit to switch dipped and main beams on and off, managing the sidelamps as a function of the status of the lighting control stalk. The front and rear foglamps are kept switched off until the next request from the driver. The BSI controls via the instrument panel the lighting or extinction of the warning lamps as a consequence.