1. Remove the collector cover.
2. Disconnect the ground cable from battery.
3. Remove the oil pressure switch. 
4. Connect the oil pressure gauge to cylinder block.
5. Connect the ground cable to the battery.
6. Start the engine, and measure the oil pressure.
Oil pressure:
Standard
98 kPa (1.0 kgf/cm2, 14 psi) or more (at 600 rpm)
294 kPa (3.0 kgf/cm2, 43 psi) or more (at 5,000 rpm)
• If the oil pressure is out of specification, check oil pump, oil filter and lubrication line.
• If the oil pressure warning light is ON and oil pressure is within specification, check the oil pressure switch.
NOTE:
Standard value is based on an engine oil temperature of 80°C (176°F).
7. After measuring the oil pressure, install the oil pressure switch.