Audi Workshop Service and Repair Manuals

Note:

Function test and repair of optical and acoustic oil pressure display:

Visual and acoustic oil pressure indicator

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations

Test requirements

• ● Oil level OK
• ● Oil pressure warning lamp (K3) must light with ignition switched on.
• ● In vehicles with auto check system display OK must illuminate (call up symbol).
• ● Engine oil temperature approx. 80 °C (vent for radiator must have run once).

Checking oil pressure switch.

• ‒ Disconnect wire from oil pressure switch.

• ‒ → Unbolt oil pressure switch and screw in oil pressure testing device V.A.G 1342.
• ‒ Connect wire -2- (brown) to earth (-).
• ‒ Connect wire -1- (blue) to oil pressure switch.
• ‒ Attach diode test lamp V.A.G 1527 to line -1- and battery positive (+).
• ‒ Start engine and gradually raise rpm. At 1.6 ... 2.0 bar overpressure the LED lamp must be illuminated, otherwise replace 1.8 bar oil pressure switch.

Function of dynamic oil pressure warning system

Testing warning lamp

After ignition on (terminal 15 on) and engine not running the oil pressure warning lamp flashes (not in vehicles with auto checking system).

Warning criteria:

Engine not running; oil pressure switch closed.

Coolant temperature higher than 60°,engine speed higher than 1500 rpm and oil pressure switch opened.

Coolant temperature lower than 60°, engine speed higher than 300 rpm and oil pressure switch opened.

With engine speed higher than 5000 rpm an active oil warning does not go out, independent from condition of oil pressure switch.

If the voltage supply of the control unit is OK (terminal 15) and if oil pressure switch above 1500 rpm is opened for longer than 0.5 s during engine running this occurrence is stored. If this condition occurs three times during "terminal 15 on" the warning becomes or remains active even below 1300 rpm.

Check oil pressure

• ‒ → Unbolt oil pressure switch and screw in V.A.G 1342 (oil pressure sender is not installed in A4).
• ‒ Screw oil pressure switch intoV.A.G 1342.
• ‒ Start engine.
• ‒ Engine oil temperature at least 80 °C.
• ‒ Oil pressure at idling speed 1 to 2.5 bar
• ‒ Oil pressure at 3000 rpm 3 to 5 bar