total electrical failure?

[saturnfive]

After some considerable reading of the haynes manual electrical diagrams I've come across reference to a few fuseable links. There appears to be one labelled FL4 that is drawn as if it is in the engine fusebox next to fuse F22.

I'm not aware of there being such a thing on my car but perhaps they are hidden in another box below? The only mention the haynes manual makes of fuseable links is to say that if a fuseable link blows it should be dealt with by a dealer as its a serious fault.

Stopping the engine mid drive and all lights is pretty serious so it sounds like a good port of call.

There doesn't appear to be one drawn between the battery and the engine fuse box if the diagrams are accurate representations of locations. It's sort of represented as if it's in the fusebox. FL4 appears in other circuit diagrams as well so it might be the cause of so many systems being without power.

[ASt85]

Originally Posted by saturnfive

When you say antenna ring, is this something which is connected to the central locking for security. The central locking is completely dead.

The antenna ring sits around the lock barrel, identifies the chip in the key and once identified enables the starter via the CanBus by sending a voltage to that spade terminal outlined in the photo of the solenoid that sits on top of the starter. Without that "signal" voltage the starter will not crank.

[BarryCambs]

Have you checked the voltage within the fuse box (s)?

[saturnfive]

Originally Posted by BarryCambs

Have you checked the voltage within the fuse box (s)?

Not yet. Put the CEM back together and checked all the relays. All match each other in impedance between the pins so its not them. CEM looks immaculate but that's not to say that the chip hasn't gone pop inside. Looks good on the outside.

Took the engine fusebox apart and discovered that underneath there are four 60 Amp fuses clamped down with thread locked nuts. All have 1 Ohm resistance across them so they don't look to have failed. Got it all put back together and the problem remains identical. Looking at the wiring from the +ve post in the engine bay, I understand why there is power to the units. The post splits off a heavy cable which goes to the starter motor direct and is not controlled by a computer at that point. I'm guessing that the same is true for fuel pump etc. which is why sounds come on in the engine bay when the ignition key is turned but there is no command from the computers to actually activate.

Think it's likely to be a computer module which has failed. No central locking and nothing at all on the Drivers Information Module means that there is no point looking for starter issues until these are fixed. If the system is going to run it will have to have a working DIM.

Will pull fuses individually and see which has 12v to them or not. Perhaps some of them will not be powered anyway until a computer demands them to be powered through some other switching.

Seems I have two options, send the DIM off for a recondition and see if it is at fault. I know that it's check engine bulb is not working because it doesn't illuminate during normal ignition switching before start. (nothing illuminates now of course after the total failure) I should get it sorted anyway and it might be responsible for the communication problems. Perhaps it is actually trying to illuminate as other owners have previously described a DIM failure with only the check engine light illuminated.

Next option is to buy a vida dice system while I still possess the DIM in the car and hope that it will be able to make contact with all the computers and find out if they are knackered or not whether there are any breaks in the cables they use to communicate with each other.

If the Upper Electronic module in the central mirror has failed it might explain the loss of central locking. It might also mean that an immobiliser type situation has developed whereby everything is dead (like it is). Just guessing really without the Vida.

[wynnj]

With such a major failure and no obvious cause I would definitely go down the VIDA route. If you're planning on keeping this car or getting another volvo in the future it'll more than pay for itself in time and peace of mind.

[saturnfive]

Had a friend pop round with a snap-on laptop for reading codes. His machine previously one year ago was able to read all sorts of things on the car. Now it says that it's unable to communicate with the CEM. Sounds like either the CEM has failed or the harness powering the CEM has failed.

I'm thinking the next best step is to try to work out whether there is power to the CEM. Does anyone know which of the millions of cables actually power the board?

I'm loathed to spend a load of money on Vida if it just tells me that it can't communicate with the CEM as well. I'm also loathed to send off the CEM for repair in case it's not that and it is in fact a wiring harness issue which will almost certainly be very involved to fix.

Just mulling over whether its worth spending any more time and money on it

If anyone knows which pin/pins on the plug should be at 12v for the CEM it would be very helpful. It would at least rule out a harness issue and mean that it's worth me spending the money on the Vida kit and trying to get the CEM reconditioned.

Can the Vida dice software reprogram a CEM from a breakers yard if mine turns out to be beyond repair? Just a bit concerned that if mine is totalled I might end up having to go to the stealers for a brand new one. It's definitely not worth doing that.
Cheers

[Ripmax]

Hi,

Make one more post then you can PM. Send me your email and i'll send you a copy of the official Volvo wiring diagrams.

Technically yes, VIDA can reprogram it but not without downloading (and paying for ) the software. It's easy to cause more problems doing this. Unfortunately that's a job I personally would hand over to a specialist.

[saturnfive]

Thanks Ripmax,

I'll send you a PM

[XC70Bob]

If you end up needing the CEM repaired or one reprogramming I would recommend volvodiagnostic.com used by many on this forum.
lots of recommendations here https://www.volvoforums.org.uk/showthread.php?t=143579

Used them for a replacement DEM first class service.

[saturnfive]

Originally Posted by XC70Bob

If you end up needing the CEM repaired or one reprogramming I would recommend volvodiagnostic.com used by many on this forum.
lots of recommendations here https://www.volvoforums.org.uk/showthread.php?t=143579

Used them for a replacement DEM first class service.

Thanks XC70Bob

I spoke to him a couple of days ago about the possibility and he seemed to indicate that it was unlikely on a 2000 my car. I'll give him another call tomorrow and see if he can check out the CEM and the DIM together.