1997 MERCEDES-BENZ ML500 service interval

GF00.20-P-2009A
Engine oil monitor function
24.10.96

MODEL
129 with ENGINE 112, 113

MODEL
163 with ENGINE 112, 113, 612

MODEL
168 with ENGINE 166, 668

MODEL
202 with ENGINE 112, 611

MODEL
208 up to 31.7.99 with ENGINE 112, 113

MODEL
210 up to 30.6.99 with ENGINE 112, 113, 611

General

The oil level is constantly monitored by the oil sensor, and the

appropriate data transmitted to the processor by the ASSYST.

Oil replenishments are detected automatically and result in a bonus,

which extends the service interval accordingly.

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:
D
at driver request

Display of warnings: D
automatically, at the earliest 60 s after engine start and oil

temperature greater than 60°C:

D
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 displaly, "HI" appears flashing.)

D
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.)

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D

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.)

D
automatically 13 s after ignition ON:

D
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")

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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

D
up to 20°C
30 minutes

D
from 60°C
1 minute

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

temperatures.

Possible readouts are (text in parenthesis relates to models not fitted

with multifunction display.):
D
"OIL LEVEL OKAY" ("o.k."),

D
1.0L, 1.5L, 2L,

D
"Overfilling" ("HI"),

D
"OBSERVE WAITING TIME" (clock symbol flashing and oil can

symbol),

D
"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)).

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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:

D
current kilometer reading rounded off to 100,

D
total oil replenishments in the last interval,

D
remaining distance,

D
remaining time,

D
product of the quality factors,

D
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
D
With the
HHT
it is possible to retrieve the last 10 oil

replenishments and the corresponding kilometer readings of

the current interval.

D
In the normal case, detection of an oil replenishment is

displayed by the remaining distance in the instrument cluster

being extended

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d by Modification services.
Page 1

Oil replenishments are always only detected once the following

conditions are met:

D
the replenished quantity is
at least 1 l

D
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.
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.

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.

P00.20-0201-06

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.

P00.20-0204-06

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.

Copyright DaimlerChrysler AG 05.06.2006 CD-Ausgabe G/10/04 . This WIS print-out will not be recorde
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Page 2

P00.20-0202-06

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.

If oil is now topped up after 5 000 km (a), the

remaining distance displayed is not extended

as the curve is within the shaded area. The

bonus B1 is nevertheless added internally

and results in an extension of the service

interval to slightly more than

15 000 km - provided the driving conditions

remain the same or are more favorable.

(The service interval of 15 000 km is always

reached, however, even if the internal value

were less.)

P00.20-0203-06

Example 4:

Oil has been topped up after 5 000 km under

unfavorable driving conditions (a) and the oil

replenishment (bonus B1) detected internally.

We now have two cases to consider:

D
If the car continues to be driven under

the same conditions (unbroken line), the

remaining distance displayed is not

extended as the curve is within the

shaded area.

The service interval in this case is

nevertheless 15 000 km although the

internal value is less. (The remaining

distance displayed can always only be

within the light area.)

D
If the car continues to be operated

under more favorable conditions

(broken line), the value of the internal

remaining distance slowly moves into

the light area. Consequently, the service

interval may be greater than

15 000 km.


Active service system survey of display

facilities

GF00.20-P-0003-04A


Active service system technology/ influencing

variables

GF00.20-P-0003-05A


Active service system survey

model/engine/sensor/instrument cluster

GF00.20-P-0003-06A


Active service system (ASSYST) operating

instructions, resetting

GF00.20-P-0003-01A

Oil sensor position/task/function
Oil sensor position, task, function

GF18.40-P-4111A

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d by Modification services.
Page 3

Fig. 318: Identifying Active Service System (ASSYST) Display
ACTIVE SERVICE SYSTEM (ASSYST) INFLUENCING PARAMETERS - GF00.20-P-0003-05A
The values of various influencing parameters are required by ASSYST for calculating the demand-based service
interval, and these are included in the calculation of the service interval as weighting factors . There are two
versions within ASSYST, the difference being in the oil level sensors fitted:
The familiar oil level indicator switch (S43) is fitted to engines (104, 111, 119, 120, 602.982, 604, 605,
606). In view of the fact that this is a switch, it is only possible to detect if the oil level drops below the
minimum level.
The oil sensor (oil level/temperature/quality, B40) is used on more recent engines (e.g. 112, 113, 166,
611, 668). This sensor consists of 2 capacitor systems with the engine oil as an insulator. If the water
content of the oil or the oil level changes, there is a change in the capacitance of the "capacitor".
The capacitance is thus a measure for the oil level.
In addition, the oil sensor (oil level/temperature/quality, B40) contains a temperature sensor which
detects the temperature of the engine oil.
All the signals are processed in the electronics integrated in the sensor to form a PWM (pulse width
modulated) signal, and passed to the engine control module (N3).
In addition to the weighting factors, which depend on reallife driving conditions, quality factors are also used
for calculating the demand-based service interval (remaining distance and remaining time).
Survey of ASSYST influencing parameters
Weighting factors (dependant on reallife driving conditions):
Load torque
Engine speed
Oil level
Engine oil temperature
Oil correction factor (is used as comparative value for determining oil level)
Coolant temperature
These data are supplied by the injection system control module (N3) to the service microprocessor over
the CAN.
The data relating to oil level, engine oil temperature and oil correction factor are supplied by the oil
sensor (oil level/temperature/quality, B40) through the injection system control module (N3), and are
therefore only available on engines fitted with this sensor.
Quality factors (these are factory-set to base values and can be changed with the HHT, if operating
conditions of the vehicle so necessitate; they influence the start distance):

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ACTIVE SERVICE SYSTEM (ASSY ST) FUNCTION - GF00.20-P-0003A
MODEL 129 with ENGINE 112, 113
MODEL 163 with ENGINE 112, 113, 612
MODEL 168 with ENGINE 166, 668
MODEL 202 with ENGINE 112, 113, 611
MODEL 208 with ENGINE 112, 113
MODEL 210 with ENGINE 112, 113, 611, 612, 613
General
The "Active service system (ASSYST)" draws the attent ion of the driver to a service which is due.
ASSYST is a demand-activated engine oil service system. In other words, in addition to the pure time and
distance criterion, various factors are taken into account for calculating the demand-oriented service intervals.
These are on the one hand quality factors which are c oded with the HHT, and on the other hand weighting
factors which take into account driving conditions and thus actual wear and tear.
Fig. 319: Identifying Text Panel And Tool Symbol
engines 602, 606 for
in addition engine 605 LA

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1998-2005 GENINFO Overall vehicle - 163 Chassis
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REMAINING DISTANCE FUNCTION - GF00.20-P-2007A
MODEL 129 as of 1.6.97
MODEL 140 as of 1.6.97
MODEL 163
MODEL 168
MODEL 170 as of 1.6.97
MODEL 202 as of 1.6.97
MODEL 208 up to 31.7.99
MODEL 210 as of 1.3.97 up to 30.6.99
The service intervals which are possible with ASSYST range
on engines with oil sensor (e.g. 112, 113, 166, 611) between 15 000 and 30 000 km,
for the new direct injection diesel engine 668 between 20 000 and 40 000 km,
for engines with oil level switch between 15 000 and 22 500 km (for engine 602.982 between 20 000 and
30 000 km).
The service interval achieved depends on the start distance and the driving conditions (cf. remaining
distance).
Start distance and remaining distance
Start distance refers to the service interval in km/miles which is the minimum distance which may be driven
until the next service. On engines with oil sensor (e.g. 112, 113, 166, 611, 668) this applies only, however, if the
specified quantity of oil has been added during the oil change.
The start distance is dependent on:
the set quality factors
(The quality factors are factory-set to a basic setting. They can be altered with the HHT, if operating
conditions so necessitate.)
The start distance is not dependent on the driving conditions (weighting of the distance driven) and on any oil
replenishments .
The standard value is normall
y 15 000 km, for the new direct injection diesel engine 668 20 000 km.

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1998-2005 GENINFO Overall vehicle - 163 Chassis
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The figure may differ from this, however, depending on quality factors.
The start distance is automatically reset to its initial value by the oil change reset each time the oil is changed.
The start distance is an internal computed quantity and cannot be displayed in the instrument cluster. It is
possible to display the start distance with the HHT.
What is normally displayed in the instrument cluster is the remaining distance .
The remaining distance is the same as the start distance immediately after the oil change. On engines with oil
sensor (e.g. 112, 113, 166, 611, 668) this applies only, however, if the specified quantity of oil has been added
during the oil change.
The remaining distance is the distance which remains from the current kilometer reading until the next
service. The possible length of the interval is at least as great as the remaining distance displayed
immediately after an oil change, and is at the most twice the start distance.
The remaining distance is dependent on
the start distance
the driving conditions (a weighting of the distance driven takes place)
any oil replenishments in the case of engines with oil sensor (e.g. 112, 113, 166, 611, 668)
Consequently, ASSYST also takes into account the driving conditions: In the case of a favorable weighting
(e.g. small number of cold starts, no high engine revs, small number of short-distance trips, minimum extent of
towing a trailer etc.) and oil replenishments, the driver is provided with a bonus which extends the remaining
distance and thus the service interval. Account is also taken of whether the vehicle is actually driven or whether
the engine runs at idle speed. ASSYST is constantly supplied with the data regarding the current operating
conditions of the vehicle for this purpose.
In the case of the best weighting , only 0.6 km are added for each kilometer driven.
In the case of the most unfavorable weighting of the distance (e.g. frequent short-distance trips, large number
of cold starts), the remaining distance and thus the service interval is smaller than in the case of the most
favorable weighting (assuming identical quality factors).
In the case of the most unfavorable weighting, up to 3 km are added for each kilometer driven.
The start distance and the remaining distance are once again presented in the form of a graph in the diagram
opposite, taking the example of gasoline engines
Each time the oil is changed, the start and remaining distances are set to the initial value. In this case, the
normal value of 15 000 km is entered as the start distance (top bar) (shaded + dark section). The start distance
may differ from 15 000 km (e.g. 14 000 km; shaded section) if the quality factors do not correspond to the basic
setting. In the case of engines fitted with oil sensor (e.g. 112, 113, 166) the start distance may also be less than
15 000 km if the specified oil quantity was not added during the oil change. The remaining distance (bottom
bar) is always 15 000 km, however, immediately after an oil change. In addition, the service interval is
always at least 15 000 km .

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The total remaining distance and thus the service interval may be increased to not more than twice the start
distance, 30 000 km in this case (white section) as a result of corresponding bonuses (favorable weighting of
distances driven) and in the case of engines fitted with oil sensor (e.g. 112, 113, 166).
Fig. 321: Start And Remaining Distance Graph

However, a start distance of less than 15 000 km results in a reduction in the maximum attainable service
interval.
Refer also to the diagrams in the document "Engine oil monitoring".
Warning threshold (km)
With the HHT it is possible to set a warning threshold between 250 km and 8000 km for the remaining distance.
This warning threshold is set differently for 3 different distances driven. The system adjusts to the correct
annual distance driven by calculating the daily distance driven (refer to table):
Display of remaining distance (The readout is shown in kilometers or miles depending on the national code.):
at driver request
automatically, after 5 s start switch in position 2 or driving if the warning threshold is reached :
The warning symbol and the readout: "SERVICE IN .... KM" appears for 10 s. (On models not fitted with
multifunction display, the service symbol appears together with the remaining distance in kilometers,
from mid July 97 "... km".)
automatically, after 5 s start switch in position 2 or driving if the remaining distance is exceeded :
In this case, the readout "KM .... EXCEEDED" appears together with the service symbol for 30 s (up to
mid July 97 for 10 s). (On models not fitted with multifunction display, the service symbol appears
together with the remaining distance with a negative sign in kilometers as a flashing display, as of mid
July 97 "... km".)
As of approx. 06.97 a brief warning signal sounds in addition.

2004 Mercedes-Benz ML350
1998-2005 GENINFO Overall vehicle - 163 Chassis
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Saturday, October 02, 2010 3:47:47 PMPage 205 © 2006 Mitchell Repair Information Company, LLC.