Oil Pressure Switch (For Fuel Pump): Testing and Inspection

Oil Pressure and Oil Pressure Switch, Checking

Special tools, testers and auxiliary items required
^ Oil pressure gauge V.A.G 1342
^ Adapter V.A.G 1342/14
^ Voltage tester V.A.G 1527 B
^ Connector test set V.A.G 1594C

Note:
^ Function test and servicing the optical and acoustic oil pressure indicator.

Test Conditions
^ Engine oil level OK.
^ Engine oil temperature at least 80 degree C (radiator fan must start up once)
^ Selector lever must be in position "P" or "N".

Oil Pressure Switch
- Remove insulation pan.
- Unscrew sealing plug from oil filter housing.
- Seal test hole for oil pressure switch on oil pressure tester V.A.G 1342 using sealing plug for oil filter housing.
- Screw oil pressure tester V.A.G 1342 with adapter V.A.G 1342/14 into oil filter bracket in place of sealing plug.

Note:
^ Note installation position of adapter. The conical connecting neck of the adapter is screwed to the pressure hose of the tester.

- Connect brown wire of tester to ground (GND)(-).





- Connect diode test lamp V.A.G 1527 B to B+ and oil pressure switch (connection in engine compartment - arrow - ) using adapter cables from connector test kit V.A.G 1594C. LED must not light up.

If the LED lights up:

- Replace oil pressure switch F1

If the LED does not light up:

Note:
^ While starting engine, watch pressure tester and LED as switch point of oil pressure switch may already be exceeded during start.

- Start the engine and run at idle speed. AT 0.7 to 1.1 bar positive pressure, light diode must come on. Otherwise, replace oil pressure switch F1.

Oil Pressure
- Check oil pressure at different speeds:

^ 1500 RPM: at least 1.7 bar
^ 2000 RPM: 3.0 to 5.5 bar pressure
^ above 2000 RPM: maximum 7.0 bar

- If the specified values are not reached:
- First check control piston of oil pressure relief valve in oil pump for soiling.
- To do so, first unscrew sealing plug from cylinder block, then unscrew sealing plug from oil pump.

Note:
^ Control piston of oil pressure relief valve is spring-loaded. Therefore the highest care is required when screwing the sealing plug.
^ The locking bolt is tightened in oil pump to 35 Nm.

- Pull control piston out of oil pump and remove soiling if necessary.
- Then check strainer in oil intake connection for contamination.
- Also check oil pipe on cylinder block at bottom for leaks. Replace sealing rings if necessary.
- Correct mechanical damage, e.g. bearing damage.

At higher engine speeds oil pressure must not exceed 7.0 bar

If a malfunction is found despite insufficient oil pressure:

- Replace oil pump.

If the specification is exceeded:

- Check oil channels.
- Replace oil pump.