2005 MERCEDES-BENZ SPRINTER buttons

ule (ECM) over the Controller Area Network (CAN)
data bus. The low oil level indicator Light Emitting
Diode (LED) is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster detects that the ignition switch is in the On
position. Therefore, the LED will always be off when
the ignition switch is in any position except On. The
LED only illuminates when it is provided a path to
ground by the instrument cluster transistor. The
instrument cluster will turn on the low oil level indi-
cator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the low oil level indicator
is illuminated for about two seconds as a bulb test.
²Engine Oil Level Low Message- Once the
engine has been started, each time the cluster
receives a message from the ECM indicating that the
engine oil level is at or near the ªMinimumº mark on
the dipstick, the low oil level indicator is illuminated.
The indicator remains illuminated briefly at first, but
will remain illuminated for longer periods as subse-
quent messages indicate that the oil level has
dropped further. Eventually, the indicator will
remain illuminated solid until the engine oil level is
corrected, or until the ignition switch is turned to the
Off position, whichever occurs first.
The instrument cluster also supplements the oil level
indicator by displaying an engine oil icon along with
alpha-numeric messages in the multi-function indicator
Liquid Crystal Display (LCD) advising the vehicle oper-
ator how much oil is required to correct the engine oil
level, and when the ªMaximumº engine oil level has
been exceeded. See the owner's manual in the vehicle
glove box for more information on this feature.
The ECM continually monitors the engine oil level
and temperature sensor to determine the engine oil
level. The ECM then sends the proper engine oil
level messages to the instrument cluster. If the
instrument cluster turns on the indicator after the
bulb test, even after the engine oil level is sufficient,
it may indicate that the engine or the engine oiling
system requires service. For proper diagnosis of the
engine oil level and temperature sensor, the ECM,
the CAN data bus, or the electronic message inputs
to the instrument cluster that control the low oil
level indicator, a DRBIIItscan tool is required. Refer
to the appropriate diagnostic information.
MAINTENANCE INDICATOR
DESCRIPTION
An Active Service SYSTem (ASSYST) engine oil main-
tenance indicator is optional equipment on all instru-
ment clusters. In vehicles so equipped, a second,dedicated ASSYST microprocessor is integral to the
cluster electronic circuit board. The ASSYST indications
are displayed and can be toggled with the clock indica-
tion on the right side of the multi-function indicator
Liquid Crystal Display (LCD) located near the lower
edge of the instrument cluster, directly below the speed-
ometer. The ASSYST displays include numeric values
combined with several icons to indicate actual engine oil
level, and reminders in time (days) or distance (miles or
kilometers) until the next required engine oil mainte-
nance is anticipated. ASSYST also provides several
audible indications using the electronic tone generator
on the instrument cluster circuit board to supplement
these visual displays.
The indications of the ASSYST engine oil mainte-
nance indicator are not visible when the LCD is not illu-
minated. When illuminated, the ASSYST indications
appear as dark characters and icons silhouetted against
an amber field. When the exterior lighting is turned Off,
the display is illuminated at maximum brightness.
When the exterior lighting is turned On, the display
illumination level can be adjusted in concert with the
cluster general illumination lighting using the ª+º (plus)
and ª2º (minus) multi-function indicator push buttons.
The ASSYST engine oil maintenance indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The ASSYST engine oil maintenance indicator micro-
processor uses numerous criteria besides time and mile-
age to evaluate vehicle maintenance requirements. Time
data is taken from the electronic digital clock integral to
the instrument cluster. Vehicle distance data is obtained
from the Controller Antilock Brake (CAB) over the Con-
troller Area Network (CAN) data bus. Coolant tempera-
ture, engine oil temperature, engine oil level, engine oil
quality, engine speed, and engine load data are obtained
from the Engine Control Module (ECM) over the CAN
data bus. Using all of the available data and internal
programming, the ASSYST microprocessor then calcu-
lates the estimated time and distance to the next
required engine oil maintenance interval. The ASSYST
uses the multi-function indicator LCD to display that
data and, when necessary, issues audible alerts to the
vehicle operator through the electronic tone generator
on the cluster circuit board.
See the owner's manual in the vehicle glove box for
more information on the features, use, operation and
resetting procedures for the ASSYST maintenance
computer. Proper diagnosis and testing of the
ASSYST engine oil maintenance computer, the CAN
data bus and the electronic data bus message inputs
to the EMIC that are used by the ASSYST computer
for its calculations requires the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
VAINSTRUMENT CLUSTER 8J - 19
LOW OIL LEVEL INDICATOR (Continued)

MALFUNCTION INDICATOR
LAMP (MIL)
DESCRIPTION
A Malfunction Indicator Lamp (MIL) is standard
equipment on all instrument clusters. The MIL is
located near the lower edge of the instrument cluster, to
the right of the multi-function indicator display. The
MIL consists of the International Control and Display
Symbol icon for ªEngineº imprinted within a rectangu-
lar cutout in the opaque layer of the instrument cluster
overlay. The dark outer layer of the overlay prevents
the indicator from being clearly visible when it is not
illuminated. An amber Light Emitting Diode (LED)
behind the cutout in the opaque layer of the overlay
causes the icon to appear silhouetted against an amber
field through the translucent outer layer of the overlay
when the indicator is illuminated from behind by the
LED, which is soldered onto the instrument cluster elec-
tronic circuit board. The MIL is serviced as a unit with
the instrument cluster.
OPERATION
The Malfunction Indicator Lamp (MIL) gives an indi-
cation to the vehicle operator when the Engine Control
Module (ECM) has recorded a Diagnostic Trouble Code
(DTC) for an On-Board Diagnostics II (OBDII) emissions-
related circuit or component malfunction. The MIL is
controlled by a transistor on the instrument cluster cir-
cuit board based upon cluster programming and elec-
tronic messages received by the cluster from the ECM
over the Controller Area Network (CAN) data bus. The
MIL Light Emitting Diode (LED) is completely controlled
by the instrument cluster logic circuit, and that logic will
only allow this indicator to operate when the instrument
cluster detects that the ignition switch is in the On posi-
tion. Therefore, the LED will always be off when the
ignition switch is in any position except On. The LED
only illuminates when it is provided a path to ground by
the instrument cluster transistor. The instrument cluster
will turn on the MIL for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the MIL is illuminated as a
bulb test. The indicator will remain illuminated until
the engine is started, or until the ignition switch is
turned to the Off position, whichever occurs first.
²MIL Lamp-On Message- Each time the clus-
ter receives a MIL lamp-on message from the ECM,
the indicator will be illuminated. The indicator will
remain illuminated until the detected fault is
repaired, or until the ignition switch is turned to the
Off position, whichever occurs first. For more infor-
mation on the ECM and the DTC set and reset
parameters, (Refer to 25 - EMISSIONS CONTROL -
OPERATION).²Communication Error- If the cluster receives
no lamp-on or lamp-off message from the ECM, the
MIL is illuminated by the instrument cluster. The
indicator remains controlled and illuminated by the
cluster until a valid lamp-on or lamp-off message is
received from the ECM.
The ECM continually monitors the fuel and emis-
sions system circuits and sensors to decide whether
the system is in good operating condition. The ECM
then sends the proper lamp-on or lamp-off messages
to the instrument cluster. If the instrument cluster
turns on the MIL after the bulb test, it may indicate
that a malfunction has occurred and that the fuel
and emissions systems may require service. For
proper diagnosis of the fuel and emissions systems,
the ECM, the CAN data bus, or the electronic mes-
sage inputs to the instrument cluster that control the
MIL, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
MULTI-FUNCTION INDICATOR
DESCRIPTION
A multi-function indicator is standard equipment on
all instrument clusters. The multi-function indicator is
located near the lower edge of the instrument cluster,
directly below the speedometer. The multi-function indi-
cator consists of a Liquid Crystal Display (LCD) unit
and four push button-controlled switches that are sol-
dered onto the instrument cluster electronic circuit
board. The LCD is visible through a large rectangular
cutout in the instrument cluster overlay, while the four
switch push buttons extend through a black plastic
switch bezel located on the cluster lens directly below
the LCD. The four multi-function indicator push buttons
allow the vehicle operator to configure and adjust sev-
eral of the display features. The buttons are labeled
from left to right: ªmiº (miles) or ªkmº (kilometers), an
icon depicting an analog clock face (clock), ª2º (minus),
and ª+º (plus).
The multi-function indicator LCD displays both
alpha-numeric characters and numerous icons to pro-
vide information to the vehicle operator. The indications
of the multi-function indicator are not visible when the
LCD is not illuminated. When illuminated the indica-
tions appear as dark characters and icons silhouetted
against an amber field. When the exterior lighting is
turned Off, the display is illuminated at maximum
brightness. When the exterior lighting is turned On the
display illumination level can be adjusted in concert
with the cluster general illumination lighting using the
ª+º (plus) and ª2º (minus) multi-function indicator push
buttons. The multi-function indicator LCD unit and
push button switches are serviced as a unit with the
instrument cluster.
8J - 20 INSTRUMENT CLUSTERVA

OPERATION
The multi-function indicator has several display
capabilities including odometer, trip odometer, clock,
engine oil level data, gear selector indicator
(PRNDL), certain diagnostic information and, on
vehicles so equipped, an optional Active Service SYS-
Tem (ASSYST) engine oil maintenance indicator and
an optional outside ambient temperature indicator.
The multi-function indicator is completely controlled
by the instrument cluster logic circuit, and that logic
will allow this indication to be viewed whenever the
multi-function indicator Liquid Crystal Display
(LCD) is activated. Therefore, the indicator remains
functional regardless of the ignition switch position.
With the ignition switch in the Off or Accessory posi-
tions and the key removed from the ignition lock cyl-
inder, the display is activated when the park lamps
are turned On or, for about thirty seconds after any
one of the multi-function indicator switch push but-
tons is depressed. Otherwise, the display unit is
active for about thirty seconds after the key is
inserted into the ignition lock cylinder, and inactive
about thirty seconds after the key is removed from
the ignition lock cylinder.
The multi-function indicator ªmiº (miles) or
ªkmº(kilometers) switch push button is used to con-
trol the odometer/trip odometer display modes. The
multi-function indicator clock switch push button is
used to control the clock/outside temperature display
modes. The multi-function indicator ª+º (plus) and
ª2º (minus) switch push buttons are used to adjust
the cluster general illumination dimming level, the
clock, and other cluster settings. See the owner's
manual in the vehicle glove box for more information
on the features, use, operation and setting proce-
dures for the various standard and optional multi-
function indicator displays.
Proper testing of the multi-function indicator LCD
unit, the CAN data bus and the electronic data bus
message inputs to the instrument cluster that control
some of the multi-function indicator functions
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information. Additional details
for the odometer/trip odometer, the clock, the gear
selector indicator, the ambient temperature indicator
and the ASSYST warning and reminder functions of
the multi-function indicator may be found elsewhere
in this service information.
ODOMETER
DESCRIPTION
An odometer and trip odometer are standard
equipment in all instrument clusters. The odometer
and trip odometer values are displayed on the leftside of the multi-function indicator Liquid Crystal
Display (LCD). The LCD is soldered onto the cluster
electronic circuit board and is visible through a win-
dow with a clear lens located near the lower edge of
the instrument cluster, directly below the speedome-
ter. However, the odometer and trip odometer infor-
mation are not displayed simultaneously. The ªmiº
(miles) or ªkmº (kilometers) switch on the instrument
cluster circuit board toggles the display between
odometer and trip odometer modes by depressing the
switch push button that extends through the lower
edge of the cluster lens, directly below the multi-
function indicator LCD.
The odometer and trip odometer information is
stored in the instrument cluster memory. This infor-
mation can be increased when the proper inputs are
provided to the instrument cluster, but the informa-
tion cannot be decreased. The odometer can display
values up to 999,999 kilometers (999,999 miles). The
odometer latches at these values, and will not roll
over to zero. The trip odometer can display values up
to 999.9 kilometers (999.9 miles) before it rolls over
to zero. The odometer display does not have a deci-
mal point and will not show values less than a full
unit (kilometer or mile), while the trip odometer dis-
play does have a decimal point and will show tenths
of a unit (kilometer or mile). The unit of measure
(kilometers or miles) for the odometer and trip odom-
eter display is imprinted on the cluster overlay below
the left end of the LCD. The unit of measure for the
instrument cluster odometer/trip odometer is selected
at the time that it is manufactured, and cannot be
changed.
The indications of the odometer/trip odometer are
not visible when the LCD is not illuminated. When
illuminated the indications appear as dark charac-
ters silhouetted against an amber field. When the
exterior lighting is turned Off, the display is illumi-
nated at maximum brightness. When the exterior
lighting is turned On the display illumination level
can be adjusted in concert with the cluster general
illumination lighting using the plus and minus multi-
function indicator push buttons. The odometer has a
ªRental Carº mode, which will activate the multi-
function indicator LCD and illuminate the odometer
information for about thirty seconds after one of the
multi-function indicator push buttons is momentarily
depressed, or after the key is inserted into the igni-
tion switch lock cylinder with the ignition switch in
the Off position.
The odometer/trip odometer and the miles/kilome-
ters switch, and the miles/kilometers switch push
button are serviced as a unit with the instrument
cluster.
VAINSTRUMENT CLUSTER 8J - 21
MULTI-FUNCTION INDICATOR (Continued)

TRANSPONDER KEY
DESCRIPTION
The Sentry Key Immobilizer System (SKIS) which
communicates with the Sentry Key Remote Entry
Module (SKREEM), uses a transponder chip that is
integral to each key fob (Fig. 6). Ignition keys are
supplied with the vehicle when it is shipped from the
factory. The transponder chip is located within the
Remote Keyless Entry (RKE) fob.
OPERATION
Each Sentry Key has a unique transponder identi-
fication code permanently programmed into it by themanufacturer. Likewise, the Sentry Key Remote
Entry Module (SKREEM) has a unique9Secret Key9
code programmed into it by the manufacturer as
well. When a Sentry Key is programmed into the
memory of the SKREEM, the SKREEM stores the
transponder identification code from the Sentry Key,
and the Sentry Key learns the9Secret Key9code from
the SKREEM. Once the Sentry Key learns the
9Secret Key9code of the SKREEM, it is also perma-
nently programmed into the transponder's memory.
The Sentry Key's transponder is within the range
of the SKREEM's transponder ring when it is
inserted into the ignition lock cylinder. When the
ignition switch is turned to the ON position, the
SKREEM communicates with the Sentry Key via a
radio frequency (RF) signal. The SKREEM deter-
mines if a valid key is present based on the informa-
tion it receives from the Sentry Key. If a valid key is
detected, that fact is communicated to the Engine
Control Module (ECM) via the Controller Area Net-
work (CAN) data bus and the vehicle is allowed to
continue running. If an invalid key is received by the
ECM or no status at all is communicated, the vehicle
will stall after two (2) seconds of running. The indi-
cator light will be flashing at this point. The Sentry
Key's transponder can not be repaired. If it is faulty
or damaged, it must be replaced.
Common communication problems:
²Two transponder keys too close together.
²Speed Pass too close to transponder key.
Solid indicator that there is a system failure.
²Loss of ECM communication.
²Failed transponder ring circuit.
Fig. 6 TRANSPONDER KEY
1 - TRANSPONDER KEY FOB
2 - RKE BUTTONS
3 - INDICATOR LIGHT
4 - KEY BLADE RELEASE BUTTON
5 - KEY BLADE
VAVEHICLE THEFT SECURITY 8Q - 5