Electrical Equipment & Instructions -- Basic Knowledge -- 203 Chassis: Maintenance Mercedes-Benz C-class W204/S204

Coolant/washer fluid level voltage coding, function - GF54.30-P-4001PM

MODEL 203.0 /2 /7 as of 24.4.04 up to 31.5.05

Diagram for low washer fluid level

Scheme 18

The coolant level indicator switch (S41) and windshield washer fluid level indicator switch (S42) are connected in series and are read in by the front SAM control unit with fuse and relay module (N10/1).

Voltage coding

The switch (s 1 ) and the switch (s 2 ) are switched in parallel for voltage coding of resistor (r 1 ) and resistor (r 2 ), the values of resistor (r 1 ) and resistor (r 1 ) must be different. When the switches (s 1 , s 2 ) are open, these resistors (r 1 , r 2 ), together with resistor (r 3 ) of the front SAM control unit with fuse and relay module (N10/1), form a voltage divider, which is supplied with the constant voltage (u). The voltage (u e ) at the input of the front SAM control unit with fuse and relay module (N10/1) is thus dependent on the positions of switch (s 1 ) and switch (s 2 ) and the values of the resistors (r 1 r 2 , r 3 ). Each switch combination (s 1 , s 2 ) gives a different voltage value (u e ) at the input of the front SAM control unit with fuse and relay module (N10/1).

Evaluation

The voltage (u e ) is applied to the input of the analog/digital converter (ADC) of the front SAM control unit with fuse and relay module (N10/1). The analog-to-digital converter (ADC) converts the analog voltage into a digital value. The processor compares the digitalized values with the threshold values stored in a memory and if necessary places the corresponding message "CHECK COOLANT LEVEL" and/or "CHECK WASHER FLUID LEVEL" on the Controller Area Network bus class B (interior) (CAN-B). The instrument cluster (A1) reads these messages and actuates the multifunction display (A1p13) accordingly.

The warning messages can be acknowledged by pressing the trip odometer reset button (A1s3) on the instrument cluster (A1)

Switch status and messages

In total, the coolant level indicator switch (S41) and the windshield washer fluid level indicator switch (S42) provide the following 4 possible switch combinations, resulting in the following warning messages in the multifunction display (A1p13)

1. If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is open, no warning message appears in the multifunction display (A1p13).
2. If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is closed, the warning message "CHECK WASHER FLUID LEVEL!" appears in the multifunction display (A1p13).
3. If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is open, the warning message "CHECK COOLANT LEVEL!" appears in the multifunction display (A1p13).
4. If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is closed, the warning message "CHECK COOLANT LEVEL!" appears in the multifunction display (A1p13). The warning message "CHECK WASHER FLUID LEVEL!" has a lower priority and is therefore not displayed directly.

Coolant/washer fluid level voltage coding, function - GF54.30-P-4001PO

MODEL 203.0 /2 /7 as of 1.6.05

Diagram for low washer fluid level

Scheme 19

The coolant level indicator switch (S41) and windshield washer fluid level indicator switch (S42) are connected in series and are read in by the front SAM control unit with fuse and relay module (N10/1).

Voltage coding

The switch (s 1 ) and the switch (s 2 ) are switched in parallel for voltage coding of resistor (r 1 ) and resistor (r 2 ), the values of resistor (r 1 ) and resistor (r 2 ) must be different. When the switches (s 1 , s 2 ) are open, these resistors (r 1 , r 2 ), together with resistor (r 3 ) of the front SAM control unit with fuse and relay module (N10/1), form a voltage divider, which is supplied with the constant voltage (u). The voltage (u e ) at the input of the front SAM control unit with fuse and relay module (N10/1) is thus dependent on the positions of switch (s 1 ) and switch (s 2 ) and the values of the resistors (r 1 r 2 , r 3 ). Each switch combination (s 1 , s 2 ) gives a different voltage value (u e ) at the input of the front SAM control unit with fuse and relay module (N10/1).

Evaluation

The voltage (u e ) is applied to the input of the analog/digital converter (ADC) of the front SAM control unit with fuse and relay module (N10/1). The analog-to-digital converter (ADC) converts the analog voltage into a digital value. The processor compares the digitalized values with the threshold values stored in a memory and if necessary places the corresponding message "CHECK COOLANT LEVEL" and/or "CHECK WASHER FLUID LEVEL" on the Controller Area Network bus class B (interior) (CAN-B). The instrument cluster (A1) reads these messages and actuates the multifunction display (A1p13) accordingly.

The warning message "CHECK COOLANT LEVEL" can be acknowledged by pressing the trip odometer reset button (A1s3) on the instrument cluster (A1)

The "Check washer fluid level!" warning message is displayed after every trip cycle, it cannot be acknowledged. It is automatically acknowledged after a certain period of time.

Switch status and messages

In total, the coolant level indicator switch (S41) and the windshield washer fluid level indicator switch (S42) provide the following 4 possible switch combinations, resulting in the following warning messages in the multifunction display (A1p13)

1. If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is open, no warning message appears in the multifunction display (A1p13).
2. If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is closed, the warning message "CHECK WASHER FLUID LEVEL!" appears in the multifunction display (A1p13).
3. If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is open, the warning message "CHECK COOLANT LEVEL!" appears in the multifunction display (A1p13).
4. If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is closed, the warning message "CHECK COOLANT LEVEL!" appears in the multifunction display (A1p13). The warning message "CHECK WASHER FLUID LEVEL!" has a lower priority and is therefore not displayed directly.

The warning message "CHECK COOLANT LEVEL" can be acknowledged by pressing the trip odometer reset button (A1s3) on the instrument cluster (A1)

The "Check washer fluid level!" warning message is displayed after every trip cycle, it cannot be acknowledged. It is automatically acknowledged after a certain period of time.

Coolant/washer fluid level voltage coding, function - GF54.30-P-4001PP

MODEL 203.0 /2 /7 up to 23.4.04

Diagram for low washer fluid level

Diagram For Low Washer Fluid Level - Model 203.0 /2 /7 Up To 23.4.04. Scheme 20

The coolant level indicator switch (S41) and windshield washer fluid level indicator switch (S42) are connected in series and are read in by the front SAM control unit with fuse and relay module (N10/1).

Voltage coding

Switch (s 1 ) and switch (s 2 ) are connected in parallel for voltage coding of resistor (r 1 ) and resistor (r 2 ); the values of resistor (r 1 ) and resistor (r 2 ) must be different. When the switches (s 1 , s 2 ) are open, these resistors (r 1 , r 2 ), together with resistor (r 3 ) of the front SAM control unit with fuse and relay module (N10/1), form a voltage divider, which is supplied with the constant voltage (u). The voltage (u e ) at the input of the front SAM control unit with fuse and relay module (N10/1) is thus dependent on the positions of switch (s 1 ) and switch (s 2 ) and the values of the resistors (r 1 r 2 , r 3 ). Each switch combination (s 1 , s 2 ) gives a different voltage value (u e ) at the input of the front SAM control unit with fuse and relay module (N10/1).

Evaluation

The voltage (u e ) is applied at the input of the analog-to-digital converter (ADC) of the front SAM control unit with fuse and relay module (N10/1). The analog-to-digital converter (ADC) converts the analog voltage into a digital value. The processor compares the digitized values to the threshold values stored in memory and, if necessary, passes an appropriate message "CHECK COOLANT LEVEL" and/or "CHECK WASHER FLUID LEVEL" on the class B (passenger compartments) controller area network bus (CAN-B). The instrument cluster (A1) reads in this information and controls the multifunction display (A1p13) accordingly.

The messages can be acknowledged by pressing the trip odometer reset button (A1s3) on the instrument cluster (A1)

Switch status and messages

With the coolant level indicator switch (S41) and the windshield washer fluid level indicator switch (S42) there are 4 possible switch combinations which result in the following displays on the multifunction display (A1p13)

1. If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is open, a message does not appear on the multifunction display (A1p13).
2. If the coolant level indicator switch (S41) is open and the windshield washer fluid level indicator switch (S42) is closed, the message "CHECK WASHER FLUID LEVEL" appears on the multifunction display (A1p13).
3. If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is open, the message "CHECK COOLANT LEVEL" appears on the multifunction display (A1p13).
4. If the coolant level indicator switch (S41) is closed and the windshield washer fluid level indicator switch (S42) is closed, the message "CHECK COOLANT LEVEL" appears on the multifunction display (A1p13). The message "CHECK WASHER FLUID LEVEL" has a lower priority and is therefore not displayed straight away.

Reset, function - GF54.50-P-2010P

MODEL 203.0 /2 /7 as of 1.7.02 up to 23.4.04

Manually resetting the long-distance memory "Since reset"

1. Turn the transmitter key (A8/1) to position 2 (circuit 15 ON).
2. Select the "Since reset" display using the system selection button (S110s3) and the scroll forward/back button (S110s1) on the multifunction steering wheel.
3. Press and hold down the instrument illumination rheostat (A1r1) for 1 second.
4. The display is reset.

Manually resetting the short-distance memory "Since start"

1. Turn the transmitter key (A8/1) to position 2 (circuit 15 ON).
2. Select the "Since start" display (short-distance memory) using the system selection button (S110s3) and the scroll forward/back button (S110s1) of the multifunction steering wheel.
3. Press and hold down the instrument illumination rheostat (A1r1) for 1 second.
4. The display is reset.

Automatically resetting the short-distance memory ("Since start")

As the "Since start" display (short-distance memory) is considered for the data of one driving cycle, the contents of the "Since start" display (short-distance memory) are normally reset automatically.

If the transmitter key (A8/1) is turned to position 0 (circuit 15C), all values of the short-distance memory are reset after 4 hours. If during this time the transmitter key (A8/1) is turned to position 1 (circuit 15R ON) or to position 2 (circuit 15 ON), the erasing rate window (4 hours) is restarted

Transferring data from preceding driving cycles into short-distance memory

In many cases it can be meaningful to transfer the data from the previous driving cycles to the short-distance memory because the data for one tank of fuel should also to be recorded in the event of any interruption to the trip. The data for the entire trip can then be stored in the long-distance memory ("Since reset"). The procedure for this is as follows

1. Select the "Since start" display (short-distance memory) using the system selection button (S110s3) and the scroll forward/back button (S110s1) of the multifunction steering wheel.
2. Start the engine.
3. The "Since start" display (short-distance memory) flashes on and off for up to 2 km or miles or 2 minutes after the engine has been started.
4. While the display is flashing on and off, press and hold down the instrument illumination rheostat (A1r1) for 1 second.
5. The values of the previous driving cycle are incorporated in the long-distance memory.

If the display exceeds the maximum travel time or mileage that can be displayed, the travel time and mileage of the relevant memory are reset automatically. This preserves the relationship between travel time and mileage

After resetting, it can take up to 3 km or miles or 2 minutes until the trip computer (TRIP) has sufficient data to display correct consumption figures. During this time and depending on the adjustment (miles or kilometers) and coding of the national version of the instrument cluster (A1), 5.8 MPG, 40 l/100 km or 2.5 km/l are displayed

Reset, function - GF54.50-P-2010PM

MODEL 203.0 /2 /7 as of 24.4.04 Since start

The contents of the "Since start" trip computer (TRIP) screen (short-distance memory) can be reset manually using the instrument illumination rheostat (A1r1) of the instrument cluster (A1). The display appears from position 2 (circuit 15 ON) of the transmitter key (A8/1).

The "Since start" display is reset manually as follows

1. Activate the trip computer using the system selection button (S110s3). "Since start" is displayed on the multifunction display (A1p13) of the instrument cluster (A1) using the scroll forward/back button (S110s1) of the multifunction steering wheel.
2. Press the instrument illumination rheostat (A1r1) for t > 3 s.
3. The "Since start" display is reset.

If the transmitter key (A8/1) is in position 0 (circuit 15C) or if the transmitter key (A8/1) was removed, all values for the short-distance memory are reset after 4 hours. If during this time the transmitter key (A8/1) is turned to position 1 (circuit 15R ON) or to position 2 (circuit 15 ON), the erasing rate window (4 hours) is restarted

Once the short-distance memory has been reset there is not sufficient data available to calculate the fuel consumption correctly. As a transitional solution for this period, the display shows a calculated figure based on the individual vehicle's fuel consumption; this display varies according to the unit setting (miles or kilometers) and the national version code entered in the instrument cluster (A1). The display limit lies at 40 l/100 km

Reset, function - GF54.50-P-2010PN

MODEL 203.0 /2 /7 as of 24.4.04 Since reset

The contents of the "Since reset" trip computer (TRIP) screen (long-distance memory) can be reset manually using the instrument illumination rheostat (A1r1) of the instrument cluster (A1). The display appears from position 2 (circuit 15 ON) of the transmitter key (A8/1).

The "Since reset" display is reset manually as follows

1. Activate the trip computer using the system selection button (S110s3). "Since reset" is displayed on the multifunction display (A1p13) of the instrument cluster (A1) using the scroll forward/ back button (S110s1) of the multifunction steering wheel.
2. Press the instrument illumination rheostat (A1r1) for t > 3 s.
3. The "Since reset" display is reset.

Once the long-distance memory has been reset there is not sufficient data available to calculate the fuel consumption correctly. As a transitional solution for this period, the display shows a calculated figure based on the individual vehicle's fuel consumption; this display varies according to the unit setting (miles or kilometers) and the national version code entered in the instrument cluster (A1). The display limit lies at 40 l/100 km

Reset, function - GF54.50-P-2010R

MODELS 203 up to 30.6.02, 208 as of 1.8.99, 210 as of 1.7.99, 215, 220 with CODE (494a) USA version

The contents of the long-distance memory and short distance memory can be reset with the reset button (right-hand button) of the instrument cluster (A1)

Resetting the long-distance memory ("SINCE RESET")

1. Circuit 15 ON
2. Using the system selection button (S110s3) and scroll forward/back button (S110s1) of the multifunction steering wheel, select the "SINCE RESET" display screen
3. Operate the reset button for 1 second
4. The display is reset (see figure)

The diagram shows the "SINCE RESET" display screen (long-distance memory) after a reset.

The display screen for "SINCE START" (transient memory) resets in the same way

Manually resetting the short-distance memory ("SINCE START")

Scheme 21

1. Terminal 15 ON
2. Using the system selection button (S110s3) and scroll forward/back button (S110s1) of P54.50-2027-01 the multifunction steering wheel, select the "SINCE START" display screen (short-distance memory)
3. Operate the reset button for 1 second
4. The display is reset see scheme 170: Resetting Long-Distance Memory Display Screen - Since Reset

Automatically resetting the short-distance memory ("SINCE START")

As the "SINCE START" display (short-distance memory) is considered for the data of one driving cycle, the contents of the "SINCE START" display (short-distance memory) are normally reset automatically.

1. On model 203 resetting takes place as soon as the instrument cluster (A1) has not been activated for 4 h.
2. In models 208, 210, 215 and 220, the reset occurs when the engine is started.

Incorporation of the data from the previous driving cycle in the short-distance memory (except model 203)

In many cases it can however be meaningful to incorporate the data from the previous driving cycle in the short-distance memory, because, for example, the data for filling the tank during a holiday trip should also be recorded during any interruptions to the trip. The data for the entire trip can then be stored in the long-distance memory ("since reset").

The procedure for this is as follows

1. Using the system selection button and scroll forward/back button, select the "SINCE START" display screen (short-distance memory)
2. Start engine
3. The "SINCE START" display (short-distance memory) flashes for up to 2 miles or 2 minutes after engine start
4. When the display flashes operate the reset button for 1 second
5. The values of the previous driving cycle are incorporated in the short-distance memory If the display of travel time or travel distance exceeds the maximum display value (99:59 h or 65.535 km (40.959 miles), the travel time and travel distance of the respective memory are automatically reset This preserves the relationship between travel time and mileage. After a reset it may take as much as 3 km or 2 min until the trip computer has enough data to display the fuel consumption figures correctly. During this time, depending on the unit setting (kilometers/miles) and the national variant coding of the instrument cluster (A1), the display shows 5.8 MPG, 40 L/100 km or 2.5 km/L. Range, function «GF54.50-P-2006R»(ref-273535-S38209185462007121000000) Travel time, function «GF54.50-P-2004R»(ref-273535-S38266408372007121000000) Fuel consumption, function «GF54.50-P-2007R»(ref-273535-S26741527882007121000000) Distance, function «GF54.50-P-2008R»(ref-273535-S01315805192007121000000) Average speed, function «GF54.50-P-2009R»(ref-273535-S25700232632007121000000) Instrument cluster (IC), operating information Model 203.0/2 «GF54.30-P-0002-05PP»(ref-273535-S14277111252007121000000) Model 203.7 «GF54.30-P-0002-05PC»(ref-273535-S21716091802007121000000) Models 208, 210 GF54.30-P-0002-05B Model 215, 220 GF54.30-P-0002-05S Instrument cluster (IC), networking of components Model 203 «GF54.30-P-0002-06PP»(ref-273535-S31718967502007121000000)