I don't think so, the fuel rail seems to have the conventional supply/return and fuel pressure regulator set up.

There is a lot of electronics in this box!

Lots of chips, so it is more than a simple "relay" (And in any case, there is already a conventional PCM controlled relay)

There is a supply, earth, and (I guess) duplex can line.

There is also a supply/earth output feeding the pump.

The car seems to work just fine with the box removed and the relevant power feeds/earths bridged.

Even Volvo do not really seem to know exactly what its purpose is.

(My local Volvo dealer has always been very helpful with technical enquires, as are the other main dealerships that I deal with. So thank you if you are looking )

So I am still wondering.

Regards,

Paul