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Mercedes-Benz ML320. Service manual - part 556

An excess oil level or insufficient oil level appears in the display together with the oil can symbol.

Display of low oil level at maximum:



at driver request

Display of warnings:



automatically, at the earliest 60s after engine start and oil temperature greater than 60°C:



if oil level too high: the oil can symbol appears together with the readout "OIL LEVEL ABOVE
MAX". In addition, a brief warning signal sounds. (On models not fitted with multifunction
display, "HI" appears flashing.)



if oil level too low: the oil can symbol appears together with the readout "OIL LEVEL BELOW
MIN". In addition, a brief warning signal sounds. (On models not fitted with multifunction display,
the oil level warning lamp (A1e12) comes on and the readout "-2L" appears flashing.)



if oil at minimum: the oil can symbol appears together with the readout "OIL LEVEL MINIMUM".
In addition, a brief warning signal sounds. (On models not fitted with multifunction display, the oil
level warning lamp (A1e12) comes on.)



automatically 13 s after ignition ON:



if no oil is in engine: the oil can symbol appears together with the readout "OIL LEVEL BELOW
MIN". In addition, a warning signal sounds. (On models not fitted with multifunction display, the
oil level warning lamp (A1e12) comes on and the readout "-2L" appears flashing. In addition a
brief warning signal sounds.)

The missing oil quantity displayed no longer changes during the display. In other words, any change in oil level
cannot be observed directly at the display. The new oil level is only displayed once the conditions described
below exist.

Display of oil quantity at driver request

The text "DISPLAY OIL LEVEL?" appears 10 s after the start switch has been turned into position "2" (on
models not fitted with multifunction display, the oil can and the clock symbol are displayed).

If the reset button of the trip counter is pressed twice within one sec. during this readout, for example, "add 1.0L
oil" (or "-1.0L")

appears in the display if oil level too low. The readout appears only after the elapse of a waiting time after
engine OFF. The waiting time depends on the engine oil temperature.

It is



up to 20°C 30 minutes



from 60°C 1 minute



The waiting time is between these two limits at other engine oil temperatures.

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

Possible readouts are (text in parenthesis relates to models not fitted with multifunction display.):



"OIL LEVEL OKAY" ("o.k."),



1.0L, 1.5L, 2L,



"Overfilling" ("HI"),



"OBSERVE WAITING TIME" (clock symbol flashing and oil can symbol),



"DISPLAY OIL LEVEL" (clock and oil can symbols.)

If there is a fault at the oil sensor (oil level/temperature/quality, B40) the oil can symbol and the text "OIL
LEVEL SENSOR FAULTY" appears only 30 s after the fault has occurred.

(On models not fitted with multifunction display, the oil level warning lamp (A1e12) comes on accordingly.)

For diagnosis, read also the injection system control module (N3) with the HHT. (The instrument cluster (A1)
receives the sensor data through the CAN from the injection system control module (N3)).

Oil change

The ASSYST has to be reset each time the oil is changed. Resetting ASSYST also resets the remaining time and
the remaining distance. Resetting can be performed at the instrument cluster or using the HHT. The following
data are stored when the system is reset:



current kilometer reading rounded off to 100,



total oil replenishments in the last interval,



remaining distance,



remaining time,



product of the quality factors,



the data of the last 5 resettings in 5 data sets

These data can only be read with the HHT!

If the specified quantity of oil is not replenished when the oil is changed, the (internal) start distance is
reduced.

Detecting oil replenishments



With the HHT it is possible to retrieve the last 10 oil replenishments and the corresponding kilometer
readings of the current interval.



In the normal case, detection of an oil replenishment is displayed by the remaining distance in the
instrument cluster being extended

Oil replenishments are always only detected once the following conditions are met:

the replenished quantity is at least

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

In the charts overleaf, a number of examples of this are presented. The horizontal (x) axis represents the service
interval and the vertical (y) axis is the remaining distance in each case in km.

conditions are met:



the replenished quantity is at least 1 l



after replenishing the oil, the car must be driven a distance of at least 5 km under normal driving
conditions at an oil temperature of at least 60°C

There are instances, however, in which the readout of the remaining distance nevertheless appears implausible
after replenishing oil; according to the display, no bonus or only a small bonus has been issued. This is caused
by the fact that the remaining distance is always only displayed within a range from 15 000 km up to 30 000 km
(or 20 000 km up to 40 000 km in the case of engine 668), but internally the system calculates with the actual
values which may also be beyond this range. These internal values can only be displayed with the HHT.

horizontal (x) axis represents the service interval and the vertical (y) axis is the remaining distance in each case
in km.

The readout of ASSYST in the instrument cluster always moves within the light range.

The remaining distance calculated internally may also, however, be within the two dark ranges. These internal
values can only be displayed with the HHT.

All examples relate to gasoline engines fitted with an oil sensor.

Example 1 :

Sufficient oil was added during the oil change. This means that the starting distance is 15 000 km.

After 10 000 km oil is topped up under normal driving conditions (a). The bonus (B1) is issued and displayed.
What this means is that when the remaining distance is retrieved, a greater remaining distance is displayed.
(Provided the aforementioned conditions for detecting the oil replenishment are met.)

Oil is topped up again after a further 5 000 km (b). In this case also a bonus (B2) is issued and displayed.

If, after this, no further oil is topped up and the car continues to be driven in the same manner, a service interval
of about 24 000 km is thus achieved.

In this example, the curve moves at all points within the light range of the chart; consequently, all the oil
replenishments are displayed by increasing the remaining distance.

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

Fig. 322: Engine Oil Monitor Function - (1 Of 4)

Example 2:

The specified quantity of oil was added when the oil was changed.

The car is driven under very favorable conditions and oil is topped up after 10 000 km (a). Internally, the bonus
B1 is issued, the service interval is extended accordingly by enlarging the remaining distance. However, as the
curve is sometimes within the shaded area, only the part of B1 which is within the light area, is at first displayed
as an extension of the remaining distance. (Provided the aforementioned conditions for detecting oil
replenishment are met.)

Oil is topped up once again at 18 000 km (b). In view of the fact that the maximum service interval of 30 000
km was exceeded, the bonus B2 is not initially displayed as an extension. The entire service interval in this case
is 30 000 km.

If, from point b, the car continues to be driven under less favorable conditions, it may still also be possible now
to achieve the maximum service interval of 30 000 km because of the internal bonus B2.

Fig. 323: Engine Oil Monitor Function - (2 Of 4)

Example 3:

When the oil was changed, the quantity added was less than the specified quantity. Consequently, the start
distance is less than 15 000 km.

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

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