engine fault repair

[Dar123]

i was sat in traffic and 2015 DS5 powered down and would not restart. It says Engine fault needs repair and the engine management light has come on.

This happened without warning and there were no issues prior

AA came to assist they thought it was the battery and have suggested that its an ECU issue.

update theres power again and its permantly in Economy mode but won't start

The car is now completely dead and i haven't had any diagnostic readings

any suggestions?

[GiveMeABreak]

If it's not attempting to start or turn over, then a supply issue if the AA checked the battery. Could be the supplies and protection unit, but without any codes, it will be fishing to be honest. I would of expected the AA chap to of at least provided you with any codes from their on-board diagnostics...

At this stage, though get your breakdown to take it to your garage / dealership as it's likely to happen again if you do get it restarted.