Got this error which is either the map sensor or the pressure exchange solenoid (NOT the boost control solenoid).

Well, I've replaced the map sensor tonight and the O2 sensor and the problem is still there.
I'm not sure how to test the pressure exchange solenoid to see if it's working but I started the engine and with the car idling there was basically no voltage coming through to the solenoid at its plug.
The pipe going between the map sensor and the solenoid seems to be 'shut off'with the engine off and with it idling. I'm not really sure how this is meant to work but I suspect the map sensor should be getting atmospheric pressure at idle and manifold pressure under load? Is this right?
If that's the case then presumably removing the pipe actually at the map sensor and blowing down it should blow straight through to fresh air with ease?
Or am I talking a load of old crap?

Also, if I switch the ignition on with the test mode connectors on, will the pressure exchange solenoid switch in & out repeatedly like the boost solenoid does? At least if it's meant to I'd be able to tell if it's knackered or not.
Finally, I don't suppose it has a fuse running to it somewhere that might have gone?

Cheers!

 

http://bbs.scoobynet.co.uk/showthrea...highlight=code
see this