Audi A4

since 1994 release

Repair and operation of the car

Control bulb of level of brake fluid

Oil pressure in the Audi A4 engine is controlled by the oil pressure sensor in combination with the electronic logic unit in the combined device. In this regard the signal is already given not on the basis of only pressure of oil, and in combination with data on temperature of cooling liquid and number of turns of the engine. Criteria for inclusion of an alarm bulb:

• The engine does not work, the sensor of pressure of oil is closed.
• Temperature of cooling liquid is above 60 °C, the number of turns of the engine exceeds 1500 rpm and the sensor of pressure of oil is open.
• Temperature of cooling liquid is below 60 °C, the number of turns are higher than 300 rpm and the sensor of pressure of oil is open.
• At engine turns higher than 5000 rpm the activated signal of pressure of oil is not switched off (irrespective of position of the switch of pressure of oil).
• If during the operation of the engine on turns higher than 1500/mines sensor of pressure of oil remains open more than 0,5 with, this information remains in the computer. If this state arises three times in a row, the warning signal becomes more active and is not switched off even if the number of turns falls. From the following inclusion of ignition counting is started anew.

Oil pressure switch

In four - and six-cylinder engines different sensors of pressure of oil which isolated details for difference have different color are installed:

• Black color at the oil pressure switch from 1,4 bars in four-cylinder engines.
• White color at the oil pressure switch from 1,8 bars in six-cylinder engines.

Troubleshooting

• If the alarm bulb (sometimes with a sound signal) burns at the working engine, you have to stop at once!
• At once switch off the engine, check oil level. If everything is all right:
• Tow off the car to prevent more serious damages because of a lack of greasing.
• As the following measure check oil pressure.
• If oil pressure as it should be, you can change the oil pressure sensor (in a workshop).
• If, despite it, the lamp does not die away, the reason in the device.

Replacement of the sensor of pressure of oil