GF54.30-P-3044GM Trip Computer, Function

GF54.30-P-3044GM Trip Computer, Function

General function requirements
^ Circuit 15 On

The circuit status of circuit 15 is provided by the EIS [EZS] control unit (N73) on the interior CAN (CAN-B).

Trip computer, 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 multifunction display (A1p13) of the instrument cluster (A1) and refers to the point in time for the last reset of the short-distance memory ("AFTER START") or the long-distance memory ("AFTER RESET").

The display screen is selected by scrolling with the scroll forward and back button (S110s1) and then selecting with the system selection button (S110s3).
The steering column tube module (N80) reads in the corresponding selection over the local interconnect network (LIN) and sends it over the interior CAN to the instrument cluster.

The trip computer function is made up 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 displaying average and present consumption
^ Function sequence for remaining distance display
^ Function sequence for reset display

Display of travel distance function sequence
The travel distance is calculated in the instrument cluster from the wheel speeds. The signals of left front rpm sensor (L6/1), the right front rpm sensor (L6/2), the left rear rpm sensor (L6/3) and the right rear rpm sensor (L6/4), which define the wheel speeds for all four wheels, are read in by the ESP control unit (N47-5) and sent to the instrument cluster over the engine compartment-CAN (CAN C).
The travel distance "After start" is displayed in a range of 0 to 9999 km.

The display is reset automatically when this threshold is exceeded. The travel distance "After reset" is calculated analog to calculating the travel distance "After start", though here the display takes place in a range from 0 to 99.999 km. The display is reset automatically when this threshold is exceeded.

If the time between circuit 15 Off and circuit 15 On is t ≥4 h, the "After start" odometer will automatically be reset to zero.

The travel distance "After start" and "After reset" is counted in parallel with the trip odometer or the main odometer reading. Depending on the setting in the instrument cluster and the coded national version, the travel distance is displayed in:
- Kilometers (e.g. ECE, Japan)
- Miles (e.g. USA, Australia)

If a change is made from kilometers to miles a changeover from liters to gallons takes place automatically.

Function sequence for the time display
For circuit 15 ON a time counter in the instrument cluster adds up the time "AFTER START" or "AFTER RESET".
The "AFTER START" time is displayed in a range of t = 0 to 999 h 59 min. The "AFTER RESET" time is displayed in a range of t = 0 to 9999 h 59 min.
If the corresponding threshold is exceeded the display is automatically reset to zero.

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 coded national version the average speed display is shown in:
- km/h (kilometers per hour)
- mph (miles per hour)

Function sequence for displaying average and present consumption
The trip computer calculates the fuel consumption from the following information:
- Consumption signal from CDI control unit (N3/9) (with diesel engine) or from ME-SFI [ME] control unit (N3/10) (with gasoline engine), sent through the engine compartment-CAN
- Travel distance covered "After start" or "After reset"

Depending on the setting (kilometers/miles) and coded national version the average fuel consumption is shown in:
- l/100 km (liters per 100 kilometers)
- km/l (kilometers per liter)
- mpg (miles per gallon)

Component Identification:

The following static displays are possible:
- At vehicle standstill v = 0 km/h and circuit 15 Off a present consumption of "0 l/100 km" is shown.
- At vehicle standstill v = 0 km/h and circuit 15 On a present consumption of "0 l/100 km" is shown.
- At vehicle standstill v = 0 km/h and circuit 61 On the maximum present consumption is shown.

Function sequence for range 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 sensor, left tank half (B4/1) and fuel level sensor, right tank half (B4/2). The rear SAM control unit (N10/8) reads in the fuel level indicator signals and forwards them over the interior CAN to the instrument cluster. The average fuel consumption is calculated from the data in the short distance memory.

Function sequence for reset display
The trip computer is reset by pressing the trip odometer reset button (A1s3) for t > 2 s.
Here, the reset is only carried out for the currently displayed information.