Engine: D5244: Check engine message

[boombox]

So my 2004 V70 has on a few occasions shown a "Engine service required" message. While the message is shown, the car is in limp mode. If I turn the ignition off and on (for example if waiting at lights) the message disappears and full power is restored.

The message seems to come up if/when the engine reaches higher revs but it's not particularly consistent. I've made a couple of journeys recently where I've needed to get up to the speed of traffic and the message has not appeared.

I've had the codes read and they are:-

P0087 - fuel rail/system pressure too low
P0088 - fuel rail/system pressure too high
P0244 - turbocharger wastegate regulating valve A range/performance problem
P0571 - cruise control/brake switch A - circuit malfunction.

I don't think the last code has anything to do with the engine message I've been getting but it would certainly explain why 1 time out of 10, the cruise control system won't turn on!

Anyone any ideas where I go from here? I don't want to start throwing money at this problem if I can at all avoid it!

many thanks