Should OM603 engine overload protection switchover valve be shorted
 

I just noticed that my engine overload protection switchover valve is shorted. The top vacuum connection is capped, the other two vacuum connections are connected together by a 10cm piece of tubing. The electrical connection at the bottom is still in place.

Is it worth reconnecting it in the way that is shown on the 07.1.10.111 - 500/2 page of the vacuum wiring diagram?

Right now, it is not connected to any vacuum circuit.

Does it matter?

Yes, it should be connected, as the turbo can provide enough boost to blow the engine apart if the waste gate fails at speed.

Most likely it is bad and leaking, so the PO bypassed it to get boost. Check it for function -- if you connect a hose to each nipple, you should be able to blow through it and it must not vent out the top with no voltage applied to the solenoid. I fit is plugged or leaks, replace it. Also, verify that the pressure switch isn't shorted, too -- it's on the intake next to the boost signal line. Should be open at low pressure, closed at 15-17 psi, I think (hard to test, just make sure it is open with the engine off).

Peter