I vaguely recall the throttle body loom goes bad on these - i'm sure there was a dealer note about changing the throttle body AND loom together....i'll see if i can dig out the note somewhere.

Meanwhile, here is the WDS technical info on the throttle valve:

"Throttle valve (DK)
A throttle valve is necessary for all diesel engines equipped with a particle filter system. The throttle valve chokes the intake air to ensure that the necessary increased exhaust-gas temperatures required for regeneration of the particulate filter are reached.

The throttle valve is closed while the engine is being shut down; this reduces shaking of the engine during the shutdown.
After stopping the engine, the throttle valve is opened again"