2.4d S60 - sudden engine failure whilst driving HELP

[Orinoco Blue S60]

Hi all,

Could do with advice, as new problem with S60.

Driving at 50mph dual carriageway yesterday, car just died, had to coast to a stop with no power brakes or power steering.

Restarts for 2secs, firing perfectly on all cylinders, then dies again.

Get fault codes for injector 5 (and sometimes injector 2) for signal too high/low/none.

RAC recovered, and he's convinced its an ecu fault or immobiliser issue.

I think it's odd to have a sudden ecu failure after perfect running, and I didn't think the starter turns when immobiliser kicking in??

What DOES stand out to me, is engine cover and rocker cover etc had a degreasing the day before failure, so I reckon wiring to injectors didn't like degreaser.

Any thoughts, as RAC and Mechanic car was delivered to, feel like they're going for most dramatic issues, where in my experience with these Volvos is even tiny things cause massive seemingly unrelated issues.

Thanks in advance