Citroen C5 Estate - where's the Eolys ECU?

[MagicMark]

I've received bad news from my local Citroen garage, that my lovely 2004C5 Exclusive Estate is scrap because the Eolys ECU apparently needs replacing, but is no longer available. I've been given the following list of fault codes:
P2002, P0234, P0100 x2, P1435 and P0485.

Some of the issues with the car I was already aware of - a tyre pressure sensor keeps sending "punctured", and there's (supposedly) an issue with the cooling fan.

However it appears to be the filler cap sensor that caused the usual anti-polution warning, and stole all the power form the engine. With fault codes reset, the car seems normal - however it thinks that the filler cap is never removed, so the anti-polution warning will come back if I carry on using the car.

The garage says "Suspect Eolys ECU, FAP differential sensor and MAP sensor".

So the place to start is the Eolys ECU. However I can't find it! Can anyone tell me where the ECU is located on the car?

Thank you.
Mark

[GiveMeABreak]

We'll need your VIN first to determine engine management system you have. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.

[MagicMark]

Sorry, didn't realise that it would vary. VIN is VF7**************[VIN obfuscated, can be read by forum staff]

I should also have said: The ECU is a 1525CZ.

Mark

[GiveMeABreak]

There are no instructions on this except for the following cryptic clue regarding location:

Location: On the chassis member near to the base of the right hand B post (according to vehicle).

So I would check under the front passenger seat to see if they've bundled it up there. It looks like this:

[wheeler]

See this post> viewtopic.php?t=75170

[MagicMark]

Thank you to each of you. I looked for it, but couldn't find it. Didn't realise I'd need to remove some trim. A job for tomorrow, I think!
A question, though. Does the filler cap sensor connect to this ECU, or direct to the engine ECU?
Mark

[GiveMeABreak]

It is connected to the fuel additive ECU which is in turn connected to the BSI

[MagicMark]

Thank you. That explains why the garage thought this ECU is the most likely cause of the filler cap being always "present".
Mark

[MagicMark]

Well, I think I now understand why the box has failed. The foam under the carpet (below the expanded polystyrene) was absolutely sodden with water. So the right hand side rear is wet, but the left hand side rear is bone dry. I'm now trying to remove the carpet so I can inspect the floor pan properly. Seats out, centre console out, door trim out. Just got to figure out how to release the black plastic bit under the accelerator, and what's holding the carpet at the front centre. Nothing's ever quite simple.
Mark

[PaulC5]

If your C5 is a 2001 to 2004 model then they can be prone to water ingress in the driver's footwell. There is a topic on it on the Citroen Owners Club forum, C5 Common Problems, copied below.

12. Wet driver's footwell, mark 1 C5 (2001 TO 2004 model), mark 2 C5 (2004 to 2008 model) and mark 3 C5 (2008 on model).

Rain from the windscreen and the middle grommet of the wiper arm drips in to the cabin air intake, runs down the inside of the cabin firewall and soaks the carpet. It is a bad design of the air intake, not carried over to the mark 2 C5. I fixed this on our hatchback by putting a plate under the wiper grommet over the air intake to direct water away, put holes in the air intake to drain water before reaching the firewall, used lots of sealant behind the holes and at the firewall.

This problem has also been reported on the mark 2 C5 due to a build up of debris below the bulk head - see this topic from Mike Lane http://www.citroen-owners-club.co.uk/ci ... ment=85106

This problem has also been reported on the mark 3 C5 - see this topic http://www.citroen-owners-club.co.uk/ci ... etting-in/

[MagicMark]

Thank you, Paul, that's a useful clue. It's a 2004 C5 Exclusive Estate - one of the last of the 2001-2004 built.

I tried to inspect this area, by removing the plastic strip under the wipers. So I removed the wipers, remover the four large head torx screws that hold it down... and then realised that the ends appear to be under the bonnet hinges. Do I really have to remove the bonnet, just to get into this area?
Mark