Repair manual

Oil Circulation System
24
Oil Pressure Monitoring
On engines with a self-regulating oil pump, oil pressure is
monitored by two oil pressure switches. This is necessary
because two different oil pressures are used.
Signals Generated by the Oil Pressure
Switches
Both oil pressure switches are evaluated by the ECM.
Earlier versions used a single-stage oil pump and the oil
pressure switch was read and evaluated by Instrument
Cluster Control Module J285.
Oil Pressure Switch F22 of the 2009 Audi A4 is read
by Onboard Power Supply Control Module J519 and
made available to Engine Control Module J623 via the
powertrain CAN data bus. The oil pressure switches are
normally-open contacts, connecting to ground as soon as
the required oil pressure is developed.
Functions and Signals of the Oil
Pressure Switch
The two oil pressure switches serve to monitor the oil
pressure. Reduced Oil Pressure Switch F378, which is
connected directly to the ECM, checks for the presence of
oil pressure.
Oil Pressure Switch F22 monitors the high-pressure
level of the self-regulating oil pump, provided that it is
operating in the high pressure setting.
Legend
1 Warning bit “red oil can”
2 2 text bits
3 Change-over bit = 1
4 Switch bit
5 Signal from Oil Pressure Switch F22
6 Signal from Reduced Oil Pressure Switch F378
F22 Oil Pressure Switch
F378 Reduced Oil Pressure Switch
J285 Instrument Cluster Control Module
J519 Vehicle Electrical System Control Module
J533 Data Bus On-Board Diagnostic Interface
J623 Engine Control Module (ECM)
Powertrain CAN
Instrument Cluster CAN
Convenience CAN