x5 e70 40d fault code 4530

[320d]

As per heading. having some issues with this code. first car felt like the smaller turbo was not boosting,then after a week was pulling like a train. now fault remains and low to sluggish boost below 2500rpm. no smoke no noise. so busy with fault finding on vacuum hoses/actuators etc. any one ever heard or seen of actuall small turbo failures on these?
so far i have replaced all the vacuum lines and one of the turbo diverter valves which acted suspect but no joy.

 

[Teezoh]

Maybe check the Vacuum Control Solenoid or the small turbo actuator rod, toppie had the rod sticking randomly on his when it gave intermittent power and it was simply soot on it that required a nice clean.

Also worth cleaning the MAP sensor if you have not done so yet.

 

[320d]

Maybe check the Vacuum Control Solenoid or the small turbo actuator rod, toppie had the rod sticking randomly on his when it gave intermittent power and it was simply soot on it that required a nice clean.

Also worth cleaning the MAP sensor if you have not done so yet.

thanx Teezoh. so vacuum test will be next on the list as well as the electronic actuator for the small turbo. when pushing it down mannually seems to move freely, but will need to try and do testing via obd scanner to confirm.
map sensor i clean with every 10k service but will also check voltage to make sure all is in order.
thanx.