…which is still in use in many cars and tends to go haywire.

The newer maintenance manuals no longer refer to the old VDO sensor.
That's why I've written these little instructions here.
It should be noted that there is no longer an original Rotax spare part available.
The new piezo sensor would have to be installed here and consequently also a new display.

The first thing you should do is give the removed oil pressure sensor a good shake, as the installed mechanics can be shaken by the engine vibrations and you will hear a rattling noise. This is the quickest method….

Then the ohmmeter is used.
The oil pressure sensor is pressurized and the resistance is measured.
Here are the standard values:

and the diagram for this:

If the values differ, it is clear why the display cannot be correct and a new one must be found.
IMPORTANT: If the brass ring is still fitted to the old oil pressure sensor, this must be fitted to the new oil pressure sensor. To do this, the brass ring is removed, the old adhesive removed, cleaned and glued to the new one with Sicaflex.

The background is that by increasing the mass of the oil pressure sensor, it is no longer as susceptible to vibrations.