ECU fault maybe
 

Bit of a weird one, this morning driving into work in my 2008 S40 1.8 I had a lot of error messages come up, Power Steering failure, Anti skid temporary disabled, Alarm service required and lots more. Lots of warning lights on the dash, then I lost power steering, the mileage display turned blank, the radio turned off then I lost all power to the engine and all electrics. I managed to pull over but now the car is dead. Took the keys out, got out of the car, central locking worked but I noticed my dipped lights were on. Unlocked the car and tried the key again and a few dash warning lights came on but nothing else. Took the key out and locked the car and the headlights went out.

Absolutely no idea:shocked:

HEEEELLLLLLLP!!!!!!

Check charging and battery system and connections

Have you got the car started yet, if not, disconnect battery for a few minutes. Mine did similar to that a while back, got it checked out and did end up renewing CEM, and overhauling the Brake Control Module. Not cheap, didn't want to risk cutting out again.
Many on here will suggest remove/ clean CEM Contacts

This is usually a classic case of dirty/temperamental CEM contacts, it's very common on the earlier pre face lift cars but 2008+ had gold plated contacts in the loom which was supposed to fix this problem.

As suggested above, I'd start with cleaning the contacts. Disconnect the battery, unplug every connector going to the CEM (take a picture before so you remember where each go) and clean up both the connectors and sockets with an old toothbrush and some contact cleaner.

https://www.youtube.com/watch?v=H_M0KW3wFpI

I'll have a try at your suggested fixes on Monday and let you know how I got on . :tongwink:

Well I took the CEM apart and cleaned it. All contacts were good with no damage.
Apparently I have cooked the battery and need a new one.
I had left my side lights on and the battery went flat so had to jump start the car using a 2lt diesel ambulance which had an up rated alternator which produces a lot more Amps than my battery could take, so although the car started, my mechanic thinks that the battery got fried as it is not holding a charge now.
New battery on order, I'll update further as to if this solves the problem.

Well I fitted a new battery, car started and ran for about 30-45 seconds then stopped. All the dash warning lights and error messages came on prior to the engine stopping. Took the key out, put it back in and nothing, battery was showing approx 12.4v on my multi-meter but I've got no electrics, not even internal lights such as courtesy/foot well lights.

I think it might be a time for 5ltrs petrol and a box of matches then go and get myself another Jag.:tounge_smile:

Isn't a Jag just a Ford in a frock too, like our Volvos? :teeth_smile:

Is there anyone near you who has access to VIDA?

Messages on these cars can make things more complicated when they appear. You either need to get someone with vida or get it to a garage for a diagnosis.

can be anything from flat battery to dying alternator to CEM issue, but since you have checked those it really needs code reading and checking that the car communicate with the ECU correctly. With your CEM did you check if there has been any water marks visable at all?

If its the ECU then thats no real problem at all, can just pick up a 2nd hand ECU and get a clone onto it done by a capable garage. This is what happened to mine, seems some times these ECU's just go a bit duff.

They only other thing to check which you can do yourself is the battery in the keys.

This happened 4-5 times on my 2008 S40. I noticed it only happened when I had a front passenger or cargo in the footwell (and once after an interior valet) which led me to think someone/something disturbed an electrical connection in the CEM. Each time I would just reach underneath and ensure the wiring loom leaving the CEM under the carpet was firmly in and it would start every time. Covered 40k+ miles since last issue.

I realise this isn't a particularly technical solution but maybe worth considering that it's not the CEM, and possibly a wiring loom connected to it that needs exploring?

Hope you get it sorted.