volvo v50 d5 fault code 079

[DaffyV50]

Hi,
My v50 was down on power today below about 2k remember, home and held in the trip and it has revealed code 079.
Can anyone help please?
Cheers

[DaffyV50]

Thanks for the reply. That would suggest an Exhaust Valve Control Solenoid Circuit Low vault, more digging required to find out what that means.

I took the car to work this morning, was running normally, will see how it goes when I start it later.

[DaffyV50]

Well it ran fine again on way home but now when I do the wee trick to get the fault codes it's throwing up 4 completely different ones

[DaffyV50]

And today no fault codes, I'm lost

[DaffyV50]

Thanks for the help.
It was probably getting mostly supermarket fuel but was getting the occasional ultimate/v-power