L200 abs and traction control lights

[Designer 1965]

Having a recurring issue with 2009 2.5 L200 Diesel.
After driving for short period ABS and traction control lights come on and goes into limp mode.
Normally when going up hill. Can occur at 30 mph or more.
Fault code indicates over boost from map sensor.
I replaced EGR valve anyway because it had been playing up, old one badly coked up and sticking.
Mechanic suggested actuator for wastegate valve sticking on joint. Checked and moved freely.
Checked and replaced map sensor pipe as it had gone hard one end.
Before changing EGR valve the engine management light also came on. That's ok now. If ignition is switched off and on fault goes and car drives well.
Just before ABS and traction fault occurs there is a slight dip of engine power.

Any ideas would be welcomed.
Cheers

[Ken555]

SCV valve, common issue.

https://www.youtube.com/watch?v=kTl9AAbwC5Y

Did you notice any slight surging before hand ?

[Designer 1965]

Yes, slight dip in power before fault occurs. However, yesterday it came on at low speed and engine light came on as well and now none of the faults clear when engine turned off.
Do you still think it's suction control valve?
Thanks for info.