Repair manual

Oil Circulation System
25
Oil Pressure Monitoring
In the ECM, oil pressure switches are monitored at engine
ON and validated at engine OFF.
Validation at Engine OFF
There should NOT be a signal from a closed oil pressure
switch when the engine is switched OFF. If there is, an
electrical fault has occurred. At terminal 15 ON, a warning
is indicated in the Driver Information System display (“red
oil can” together with the fault text “Shut off engine and
check oil level”).
Warning at Engine ON
Oil pressure switches are monitored above a defined
engine speed threshold, dependent on oil temperature.
The oil pressure switches are generally monitored
when the engine is cold (up to 140°F [60°C]) and when
the engine is idling. When the engine is at operating
temperature, oil pressure switches are only monitored
at high engine speeds. If a switch is not closed, the
warning “red oil can” is indicated together with the fault
text “Shut off engine and check oil level” in the Driver
Information System display.
Oil Pressure Switch F22 is monitored as soon as the self-
regulating oil pump is operating in the high pressure
setting and engine speed exceeds a value computed from
the characteristic map (dependent on oil temperature).
If the switch is identified as being “not closed,” Engine
Electronics Indicator Lamp K149 is activated. Engine
speed is limited as well. Engine speed is indicated in the
instrument cluster as text and a yellow engine speed
symbol.
Fault Analysis Options
A diagnosis is made in the ECM by the oil pressure
monitoring function.
The status of Oil Pressure Switch F22 can be viewed
under Address Word 09, MVB 28 using a VAS Scan Tool.
Note
Text messages are only displayed for
“Validation at engine OFF” and “Warning
at engine ON” in vehicles with a Highline
instrument cluster.