Manometric oil switch (Audi A4 B6)

One of the parts of the oil filter unit is the oil switch. When there is no pressure, the switch is open, and when the switch-on pressure is reached, it closes. The oil pressure alarm is activated 10 seconds after the ignition is turned on. The switch-on delay time is 3 seconds, the switch-off delay time is approximately 5 seconds.

After turning on the ignition with the engine off, the indicator on the instrument panel should light for 3 seconds and then go out. The warning in the form of a flashing light and buzzer occurs if the oil switch is closed with the ignition on and the engine off, or if it is open at a speed of more than 1500 rpm. At an engine speed of more than 5000 rpm, the indicator light continues to light even if the switch is closed. At a speed of less than 5000 rpm, the light goes out again.

If the oil switch opens for only 0.3-3.0 seconds at speeds above 1500 rpm, this information is stored in the combined processor of the instrument panel insert. If this condition occurs three times during engine operation, the oil pressure drop alarm is immediately triggered, the alarm does not turn off even at a speed of less than 1500 rpm. The alarm turns off if the oil switch is closed for more than 5 seconds at a speed of more than 1500 rpm, and also when the ignition is turned off.

The operation of the oil switch and the oil pressure can be checked using an oil pressure tester and an LED tester. To do this, remove the oil switch and screw it into the tester, and screw the tester into the cylinder head in place of the switch.