1. Disconnect the ground cable from battery.
2. Remove the collector cover.
3. Remove the oil pressure switch. 
4. Connect the oil pressure gauge hose to the engine oil cooler.
5. Connect the ground cable to battery.
6. Start the engine, and measure the oil pressure.
Oil pressure:
Standard
98 kPa (1.0 kgf/cm2, 14.2 psi) or more (at 700 rpm)
294 kPa (3.0 kgf/cm2, 42.6 psi) or more (at 2,000 rpm)
490 kPa (5.0 kgf/cm2, 71.0 psi) or more (at 4,000 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.