Oil Pressure, Sensor/Switch Checking

Oil pressure, oil pressure switch and oil pressure sensor, checking

(Optical and acoustic oil pressure indication)

Test requirements

Oil level OK
Oil pressure warning light -K3- lights when ignition turned on
Auto-Check system indicates OK
Engine oil temperature approx. 80°C (176°F) and radiator fan must have switched on at least once

Checking oil pressure switch and oil pressure sensor electrical functions

- Disconnect harness connectors from oil pressure switch and oil pressure sensor.






- Remove oil pressure sensor or oil pressure switch and install into oil pressure tester VAG 1342.
- Connect cable -2- (brown) to Ground (GND).
- Connect cable -1- (blue) to oil pressure switch or oil pressure sensor.
- Connect VAG 1527B voltage tester to cable -1- and battery positive (B+).
- Start engine and check sensors and switches at the relevant engine speed.









Checking 0-3 bar oil pressure sensor with 0.3 bar oil pressure switch (0-3/0.3 bar sensor)






Checking 5 bar oil pressure sensor (with 0.3 bar oil pressure switch)

- If the cables to the oil pressure sensor are installed incorrectly, the Auto-Check-System will display the engine oil pressure warning symbol (oil can).


Checking oil pressure on engines with oil pressure switch. oil pressure sensor on cylinder head

Engine oil temperature at least 80°C (176°F)






- Remove oil pressure sensor and install into VAG 1342 oil pressure tester.
- Install oil pressure switch into tester.
- Start engine.

Oil pressure at idle: 1.0-2.5 bar (14-37psi)
Oil pressure at 3000 RPM: 2.7-2.9 bar (39-42 psi)

Note: With the pressure relief valve in each cylinder head a lower oil pressure is registered in the cylinder head than is actually controlled by the oil pressure control valve.
Oil pressure sensor/switch: 0-3/0.3 bar
Oil pressure indication: 0-5 bar

Checking oil pressure on engines with oil pressure sensor in upper oil pan

Engine oil temperature at least 80°C (176°F)






- Remove oil pressure sensor and install into VAG ~342 oil pressure tester.
- Install oil pressure switch into tester.
- Start engine.

Oil pressure at idle: 1.0-2.5 bar (14-36 psi)
Oil pressure at 3000 RPM: 3.0-5.0 bar (44-73 psi)

Note: If oil pressure is excessive (oil pressure relief valve jamming or incorrectly installed), the hydraulic valve lifters will be subjected to excessive pressure. The engine will cut out shortly after starting and, when attempting to restart, the starter motor will rotate the engine noticeably faster due to lack of compression.
Oil pressure sensor/switch: 0-5/O.3 bar
Oil pressure indication 0-5 bar