S40 (New) Electrics : ECU fault maybe

[moggycat]

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

HEEEELLLLLLLP!!!!!!

[SwissXC90]

Check charging and battery system and connections

[BJB]

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

[FunkyMelon]

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

[moggycat]

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

[moggycat]

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.

[moggycat]

Originally Posted by moggycat

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.