I have come across the first problem on my newly acquired Frontera. Its a 2003 2.2DTi Olympus and the turbo wasn't kicking in. Traced the fault to the actuator on the turbo not moving which led me to check for vacuum getting through the solenoid valves. I have found one stamped 24435269 that doesn't appear to operate, when I disconnect the inlet and outlet pipes and join them together the turbo actuator starts to work, although a bit slowly. I haven't checked for voltage at the connector...
Frontera B boost valve
Frontera B boost valve