Check the oil level, if necessary, add oil to the minimum mark.
Warm up the engine while driving, the oil temperature must be at least 80°C. Under normal conditions, this temperature is reached after a run of 15 kilometers.
Disconnect the wire from the oil pressure switch and unscrew the switch. The installation position of the oil pressure switch, see fig. K-1006 in clause 1.4.
Instead of a switch, screw in a pressure gauge with a corresponding flange.
Start the engine and let it idle. Take the oil pressure reading on the gauge. At idle, the pressure should be about 0.8 bar.
Install and tighten the oil pressure switch. Apply sealant to 2-H5 threads first, e.g. Loctite 242.