Trip computer, function - GF54.30-P-3044CE
MODEL 204.0/2 as of model year 2009
/YoM 08
MODEL 204.3
MODEL 204.9
Function requirements, general
- Circuit 15 ON
The circuit 15 status is sent by the electronic ignition lock control unit (N73) over the chassis CAN (CAN E) and interior CAN (CAN B).
Trip computer (TRIP) function, general
The trip computer provides data and information on average fuel consumption, trip time, average speed, travel distance and remaining range.
The trip computer provides the following display screens:
- "After start" (short-distance memory)
- "After reset" (long-distance memory)
The information is shown on the following displays in the instrument cluster (A1):
- Travel distance display (A1p7) (model 204.0/2/3/9 (except 204.077/277/375) without code (442) Comfort multifunction steering wheel)
- Multifunction display (A1p13) (with code (442) Comfort multifunction steering wheel, model 204.077/277/375)
The displayed information relates to the time of the last short-distance memory or long-distance memory reset.
The following trip computer content can be displayed:
- Selected "After start" or "After reset" display screen
- Travel distance driven "After start" or "After reset"
- Average transportation speed
- Time passed "After start" or "After reset"
- Average fuel consumption/current consumption
The corresponding display screen is selected by scrolling with the scroll forward and back button (S110s1) and then selected with the system selection button (S110s3).
The request is read in by the steering wheel electronics (N135) and sent over the steering LIN (LIN E1) to the steering column tube module control unit (N80). The steering column tube module control unit routes the request over the chassis CAN to the instrument cluster.
The trip computer is comprised of the following subfunctions:
- Display of travel distance function sequence
- Function sequence for the time display
- Function sequence for the average speed display
- Function sequence for display of present consumption (not on model 204.077/277) and composite mileage
- Function sequence for remaining distance display
- Function sequence, reset
Display of travel distance function sequence
The travel distance is calculated in the instrument cluster from the wheel speeds.
The Electronic Stability Program control unit (N30/4) reads in the signals of the left front axle RPM sensor (L6/1), right front axle RPM sensor (L6/2), left rear axle RPM sensor (L6/3) and the right rear axle RPM sensor (L6/4) directly and sends them over the chassis CAN to the instrument cluster. The instrument cluster receives the signals from the RPM sensors and calculates the travel distance.
The travel distance "After start" is displayed in a range of 0 to 9999 km. An automatic reset is performed following a travel distance "After start" overflow.
If a period of more than t = 4 h lies between the time when circuit 15 is switched off and then switched on again, then the "After start" odometer is automatically reset to 0.
If the odometer reading is between 6213.7 and 9999.9 and the distance unit is changed (e.g. from km to miles), the odometer will automatically be reset to 0. This reset cannot be revoked following a change of unit.
The travel distance "After reset" is calculated similar to calculating the travel distance "After start", although here the display is shown in a range from 0 to 99, 999 km. The display is reset automatically when this travel distance threshold is exceeded.
Depending on the setting in the instrument cluster and the national version code, the travel distance is displayed in:
- Kilometers (e.g. Europe, Japan)
- Miles (e.g. USA, Australia)
When changing over from kilometers to miles a changeover from liters to gallons takes place automatically.
Function sequence for the time display
With circuit 15 ON, the time after start is added up by means of a time counter. The display takes place over a range of 0 to 999 h and 59 min. The display is automatically reset to 0 when overflow occurs.
The "after reset" time is determined in the same manner as the "after start" time, although here the time is displayed in a range of 0 to 9999 h and 59 min. The display is automatically reset to 0 for any overflow.
Function sequence for the average speed display
The trip computer calculates the average speed from the ratio between the travel distance driven and the time passed (trip time) since the last reset of the short-distance memory or long-distance memory. Depending on the setting (kilometers/miles) and national version code, the average speed display is shown in:
- km/h (kilometers per hour)
- mph (miles per hour)
Function sequence for display of present consumption (not on model 204.077/277) and composite mileage
The trip computer calculates the fuel consumption using the following information:
- Consumption signal from CDI control unit (N3/9) (for diesel engine) or from ME-SFI [ME] control unit (N3/10) (for gasoline engine)
- Travel distance covered "After start" or "After reset"
Depending on the unit setting (kilometers/miles) and the national variant coding of the instrument cluster the fuel consumption is displayed in:
- l/100 km (liters per 100 kilometers) or
- mpg (miles per gallon) or
- km/l (kilometers per liter)
The relevant information is sent by the CDI control unit or the ME-SFI [ME] control unit via the chassis CAN to the instrument cluster.
The present consumption is shown together with the range. On model 204.044/006 the display takes the form of a bar display.
Function sequence for remaining distance display
The trip computer determines the expected range from the ratio between the current tank capacity and the average fuel consumption.
The current tank contents are recorded by the fuel level indicator sensor, left (B4/1) and fuel level indicator sensor, right (B4/2). The rear SAM control unit with fuse and relay module (N10/2) reads in the fuel level indicator sensor signals and forwards them over the interior CAN to the instrument cluster. The average fuel consumption is gathered from the short-distance memory or long-distance memory.
Function sequence, reset
The TRIP computer is reset in the "Resetting values" menu by pressing the OK n/(S110s6) in the left multifunction steering wheel button group (S110).
Here, the reset is only carried out for the currently displayed information. The corresponding selection is read in by the steering wheel electronics and transmitted via steering LIN to the steering column tube module control unit. The steering column tube module control unit routes the signals over the chassis CAN to the instrument cluster.
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