Trip computer, function - GF54.30-P-3044GM

MODEL 164.1 as of model year 2009

MODEL 164.8, 251.0/1 as of model year 2009

Function requirements, general

Terminal 15 ON

The EZS control unit (N73) sends the circuit 15 status over the interior CAN (CAN B) to the instrument cluster (A1).

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 in the multifunction display (A1p13) in the instrument cluster.

The displayed information relates to the time of the last short-distance memory or long-distance memory reset.

The following content can be shown on the trip computer:

Selected display screen "After start" or "After reset"
Travel distance driven "After start" or "After reset"
Average transportation speed
Time passed "After start" or "After reset"
Average fuel/present consumption

The corresponding display screen can be selected using the left multifunction steering wheel button group (S110).

The steering wheel electronics (N135) read in the control signals of the left multifunction steering wheel button group directly and send them over the steering LIN (LIN E1), steering column tube module (N80) and engine compartment-CAN (CAN C) to the instrument cluster. The TRIP function encompasses 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 on the basis of the wheel speeds. The ESP control unit (N47-5) (except model 164.195) or the regenerative braking system control unit (N30/6) (for model 164.195) sends information on the wheel speeds over the engine compartment CAN to the instrument cluster. The instrument cluster calculates the traveled distance from the wheel speeds.

The travel distance "After start" display is shown in a range of 0 to 9999 kilometer or miles. The display is reset automatically when this threshold is exceeded.

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.

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 kilometers or miles.

The display is reset automatically when this travel distance threshold is exceeded. The "After start" or "After reset" travel distance is counted in parallel with the trip odometer or the main odometer reading. Depending on the setting and coding of the national version of the instrument cluster, the travel distance is displayed in kilometers or miles.

If a change is made 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 way as the "After start" time (here, however, the display ranges from 0 to 9999 h and 59 min). If this range is exceeded, the display is automatically reset to 0.

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 sent (from CDI control unit (N3/9) (for diesel engine) or from ME-SFI [ME] control unit (N3/10) (for gasoline engine) over the engine compartment CAN to the instrument cluster)
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)

Bargraph display of present consumption (as of 1.7.09) (shown as an example using "Kilometer" setting)

Fig 1: Identifying Bargraph Display And Multifunction Display

Courtesy of MERCEDES-BENZ USA

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.
The maximum present consumption is shown at vehicle standstill v = 0 km/h and with the engine running.

The CDI control unit (with diesel engine) or the ME-SFI [ME] control unit (with gasoline engine) sends the "Engine running" signal to the instrument cluster over the engine compartment CAN.

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 fuel tank fill level is monitored 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 gathered from the short-distance memory or long-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.

Electrical function schematic, instrument cluster trip computer	MODEL 164.1 (except 164.195) as of model year 2009 MODEL 164.8 as of model year 2009	PE54.30-P-2057-97MAA
	MODEL 164.195 as of model year 2009	PE54.30-P-2057-97MAB
	MODEL 251.0/1 as of model year 2009	PE54.30-P-2057-97RAA
Overview of system components, instrument cluster (IC) component description		GF54.30-P-9996GM