Welcome! :’
I haven’t any hands on experience with the modern diesels, but the hot start problem in a petrol Saab is almost always the crankshaft position sensor.. The only check that you can do on a CPS is to check the resistance. On the Diesel engine is should be 860 ohms, but this varies a bit with temperature.
On the petrol the allowable resistance is 770 - 950 ohms. So it must be similar to the petrol one. There are 3 pins in the connector. Onli two should show a resistance across them. The third pin is a connection to the screen in the cable.
Unfortunately, since the resistance varies with temperature and the engine can get quite hot, it’s not always possible to do the check with 100% certainty, but if it’s quite high, it could be a sign of failure as they seem to fail with the resistance increasing.
The other pointer to the CPS being at fault is that the engine management will not wake up and store failure codes if it gets no signal from the CPS. So tha fact you have no codes, could point to the CPS as well.
The only certain check is to replace the CPS and try it.
