Electrical System Equipment & Instructions - Basic Knowledge - 210 Chassis: Maintenance Mercedes-Benz E-class W210/S210

Maintenance display, operating instructions - GF54.30-P-0007-02A

Display of remaining mileage at driver's request

The remaining mileage can be displayed at the request of the driver. For this purpose it is necessary to press the left button on the instrument cluster twice within one second.

The tool symbol then appears for 10 sec. together with the current remaining mileage.

Acknowledging the maintenance indicator

The display of the remaining mileage as well as the remaining time can be acknowledged and canceled by pressing the left button on the instrument cluster for at least one second. It makes no difference what caused the information to be displayed.

Resetting the maintenance indicator

The maintenance indicator can be reset to the total mileage or total time in three ways

1. Automatically when the odometer is reset to 0 within the first 250 km. (The maintenance indicator is reset to the values set at the factory).
2. Manually by driver: Hold left knob depressed and simultaneously move starter switch to position 2. Continue to hold knob down for 10 sec. After the peep tone 15,000 km appears on the display (or 7,500 miles): The remaining mileage is displayed again.
3. With the HHT.

Voltage coding of engine coolant/windshield washer fluid level, function - GF54.30-P-3006A

MODEL 129, 140 as of 1.6.96, 170, 202 as of 1.8.96, 208 up to 31.7.99, 210 as of 1.6.96 up to 30.6.99

General

The switch shown in the figure is used to determine the level of engine coolant and windshield washer fluid. The coolant level switch (S41) and windshield washer fluid level switch (S42) are connected in series. The information from both is transmitted via a single line to the instrument cluster (A1) and is voltage-encoded.

Voltage coding

Switches S 1 and S 2 are connected in parallel to resistors r 2 and r 3 to allow for voltage encoding. (The values of r 2 and r 3 must be different). When the switches are open, these resistors, together with r 1 of the instrument cluster, form a voltage divider which is supplied with a constant voltage u const .

The voltage at point p therefore depends on the position of the switches and the values of the resistors.

Scheme 6

When the switches are open the voltage at point p is given by

u p = U const * (r 2 + r 3 )/(r 1 +r 2 + r 3 )

Using the following values

r 1 =357 ohms, r 2 =110 ohms, r 3 =174 ohms, u const = 8V

u p can take on the following values according to the position of the p switches

1. Both coolant and washer fluid levels not OK: In other words, both switches are closed; r 2 and r 3 are therefore short circuited (r 2 = r 3 = 0 ohms) Thus, the voltage at point p is about 0 Volt.
2. Both coolant and washer fluid levels OK: In other words, both switches are open, all resistors are effective. Thus, the voltage at point p is about 3.5 V.
3. Only coolant level OK: In other words, s 2 is closed, s 1 is open and therefore only r 2 is effective. Thus, the voltage at point p is about 1.9 V.
4. Only washer fluid level OK: In other words, s 1 is closed, s 2 is open and therefore only r 3 is effective. Thus, the voltage at point p is about 2.6 V.
5. Interruption: If the outer circuit is interrupted, the voltage at point p is the same as uconst, in this case 8 V.
6. Other fault in system: If the voltage is outside the tolerance zones of the aforementioned values, there is a fault in the system.

The previous examples looked at the ideal case scenario. In reality, however, the values may deviate from the calculated values due to resistance tolerances and the influence of dirt on the circuit not taken into account here.

Evaluation

The voltage at point p reaches the input of the analog-to-digital converter a. The analog-to-digital converter (ADC) converts the analog voltage into a digital value between 0 and 255 (8-bit converter). This is necessary since the computer can only work with digital values. The computer compares these values with the threshold values stored in a memory chip (EEPROM) and then activates the corresponding indicator lamp(s) (A1e11) or (A1e13) accordingly. The digital value can be determined using the following formula

ADW = 255. u p / 5 V

As a precautionary measure, values which cannot be assigned to an ambiguous state (due to a fault in the system) are taken to indicate low coolant level and the low ECL indicator lamp (A1211) is actuated. A warning appears if this state is detected for at least 60 seconds.

For vehicles with electric suction-type fan (engine/AAC) (M4/3) only, e.g. M111 engine

The low ECL indicator lamp (A1e11) also comes on if a fault occurs with the electric suction-type fan (engine/AAC) (M4/3) . In this case, the lamp is actuated via the CAN data bus and the engine control module.

Diagnosis with HHT

If diagnosis is carried out using a HHT, the digital value (from 0 - 255) is displayed. In addition, the HHT also indicates the possible error by means of value tables.

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

MODEL 208 as of 1.8.99, 210 as of 1.7.99

General

The circuit in the figure is used to determine the coolant and windshield washer fluid level. The coolant level switch (S41) and windshield washer fluid level switch (S42) are connected in series. The information on both levels reaches the instrument cluster (A1) voltage coded via only one cable.

Voltage coding

The resistances r 1 and r 2 are connected in parallel with the switches s 1 and s 2 for voltage coding. (The values of r 1 and r 2 must differ).

When the switches are open, these resistances, together with r 3 of the instrument cluster form a voltage divider, which is supplied with a constant voltage u const .

The input voltage U e therefore depends on the positions of the switches and the values of the resistances.

Scheme 7

When the switches are open, the following applies to the voltage U e

U e =U const * (r 1 + r 2 )/(r 1 +r 2 + r 3 )

If the following values are inserted

r 1 = 110 ohms, r 2 =174 ohms, r 3 =357 ohms, u const =8V

U 2 can assume the following values depending on the switch positions

1. Both levels not in order: i.e.: Both switches are closed and therefore r 1 and r 2 are bridged (r 1 =r 2 =0ohms) The input voltage U e is therefore approx. 0 volts.
2. Both levels in order: i.e.: Both switches are open, all resistances are effective. The input voltage U e is therefore approx. 3.5 V.
3. Only coolant level in order: i.e.: s 2 is closed, s 1 is open and therefore only r 1 is effective. The input voltage U e is therefore approx. 1.9 V.
4. Only windshield washer fluid level in order: i.e.: s 1 is closed, s 2 is open and therefore only r 2 is effective. The input voltage U e is therefore approx. 2.6 V.
5. Open-circuit: If there is an open-circuit at a point in the outer circuit, the input voltage U e is equal to u const , 8 V in this example.
6. Other defect in system: If the voltages are outside the tolerance ranges of the above values, there is a defect in the system.

The ideal case has been considered in these calculation examples. In reality values may deviate from the calculated values due to resistance tolerances and dirt resistances which have not been taken into account.

Evaluation

The input voltage U e reaches the input of the analog-to-digital converter (ADC). The analog/digital converter converts the analog voltage value into a digital value of 0-255 (8 bit converter). This is necessary as the computer can only work with digital values. The computer compares the values supplied with those threshold values stored in a memory module and outputs the appropriate message to the multifunction display (A1p13).

The digital value of the analog/digital converter can be determined with the following formula

ADW = 255. U e / 5 V

A warning always appears only when the condition exists for at least 60 seconds

There is no message in the multifunction display (Alp13) in the event of a cable open-circuit or broken sensor. However a fault is stored in the fault memory

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 8

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

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-271979-S16492189232007111500000) Travel time, function «GF54.50-P-2004R»(ref-271979-S18053056582007111500000) Fuel consumption, function «GF54.50-P-2007R»(ref-271979-S21304080622007111500000) Distance, function «GF54.50-P-2008R»(ref-271979-S24218930302007111500000) Average speed, function «GF54.50-P-2009R»(ref-271979-S36237541262007111500000) Instrument cluster (IC), operating information Model 203.0/2 GF54.30-P-0002-05PP Model 203.7 GF54.30-P-0002-05PC Models 208, 210 «GF54.30-P-0002-05B»(ref-271979-S16602667452007111500000) Model 215, 220 GF54.30-P-0002-05S Instrument cluster (IC), networking of components Model 203 GF54.30-P-0002-06PP