Low pressure of oil can testify from need of repair of the engine. The control lamp of pressure of oil serves for the alarm system that pressure of oil the dangerously low. Even the manometer on a combination of devices shows only relative pressure. Pressure of oil is necessary for checking certificated mechanical (not electric) a manometer.
The sensor of pressure of oil is established in an end face of a head of the block of cylinders from opposite to a drive of the gas-distributing mechanism. Turn out the sensor and instead of it screw a tip of a hose of a manometer.
Connect to the engine a tachometer according to the maintenance instruction enclosed to it.
Start up the engine and warm up it to working temperature. Check pressure of oil on frequency of rotation of idling and at 3000 mines-1. If pressure is lower demanded, possibly, the gap in bearings of a cranked shaft is increased or the oil pump is faulty.