Volvo S60, T4, 2011 / 205k km’s /

I need a suggestion about the direction to look for the resolution of the following fault:

Drove the car for 150km after the change of the exhaust manifold gasket….then suddenly the engine started with “hick-ups”….then after a few seconds it indicated the DSCT fault, RPM indicator dropped to zero and the engine dropped to reduced engine performance mode. Then I could drive and got to the workshop.
Then, if I turn it on it started with problems …..rev-up-down-up-down-off, then after few times it would show DSTC error and again “reduced…”.

On the computer engine check the error was “crankshaft position sensor data fault”.

Now after the engine cooled down completely it would not even reach the “reduced mode”. It turns off after 3-4 seconds of start-up procedure.

Could anyone point me to possible faults / checks / already experienced procedures for checking the parts?!
How often it the “crankshaft position sensor” faulty?…or DSTC system that can cause such problems?


Thanks!