System Operation: Displays

Adaptive Cruise Control

The message center provides a display showing the ACC gap setting, set speed and a graphical image of a vehicle from behind.

Compass

The compass direction is displayed as a 1 or 2 character display in the message center that indicates the current direction of the vehicle (N, NE, E, SE, S, SW, W, or NW).

Digital Speedometer

NOTE: The digital speed displayed can differ slightly from the analog speedometer due to stepper motor-pointer movement and indication tolerances.

The IPC provides a redundant digital speedometer display in the message center. The digital speedometer display operates using the same vehicle speed inputs used to control the speedometer gauge. See Speedometer. Refer to: Instrument Panel Cluster (IPC) - System Operation and Component Description .

DTE/Average Fuel Economy

The DTE is calculated in the PCM using the Running Average Fuel Economy (RAFE), which is the fuel economy up to 400 km (250 miles), and the fuel level input from the fuel sender to determine how many kilometers (miles) the vehicle can be driven based on the remaining fuel in the tank. The DTE displayed value can increase, or decrease, or stay the same value depending on customer driving patterns.

The Running Average Fuel Economy (RAFE) is not transmitted over the CAN, however the IPC will show an invalid Running Average Fuel Economy (RAFE) value in Engineering Test Mode. The DTE can vary in the short term by up to 80 km (50 miles), but is usually within 16 km (10 miles). Even if the fuel economy is relatively constant, the DTE can be off over a 80 km (50 mile) range by -24% to +38%.

The DTE display and the fuel gauge both use the fuel level input from the fuel tank and engine fuel consumption to provide their respective functions. If the fuel gauge doesn't function correctly, both the fuel gauge and the DTE display are affected.

If the DTE does not function correctly and the fuel gauge is correct, then Running Average Fuel Economy (RAFE), odometer or vehicle speed related input can be invalid.

The PCM defaults to a preset baseline L/100km (mpg) when the keep alive memory is reset or PCM is flashed and changes afterward based on driving habits and conditions.

NOTE: The customer calculated DTE can be higher or lower than the DTE displayed in the message center due to changes in driving conditions. It is important to understand how the DTE is calculated and the factors that impact the DTE display when determining how to address any DTE concerns.

Since the DTE is calculated and averaged over a longer period of time (400 km [250 miles]), varying driving conditions can have a significant impact on the current or short term DTE as opposed to the displayed DTE. This difference often leads to customer complaints of incorrect or invalid DTE. The following list provides some (not all) of the driving conditions that may lead to an incorrect or fluctuating DTE concern:

Changing between towing/not towing.
Changing driving between city and highway.
Allowing the vehicle to idle for long periods of time.
Using the remote start feature frequently to allow the vehicle to warm up, particularly when parked on a grade.
Parking or driving on grades.
Inconsistent use of gasoline or E85 fuels.
Over-fueling or not filling the tank completely (trickle filling at above full, partial filling with less than 10% of tank capacity).

The PCM uses the following network messages to control the DTE.

Fuel alcohol percent
Fuel flow volume display
Fuel level display
Odometer count
Transport mode
Fuel level input from the IPC

Drive Mode

The message center provides a drive mode selection display when the driver selects a drive mode with the drive mode [G.O.A.T.] control switch. When the switch is rotated in either direction (left or right), the selected mode is displayed at the top center of the graphic display.

Forward Collision Alert

The message center provides a forward collision alert display when a possible forward collision is detected due to a short following distance to the vehicle in front and little or no driver intervention is detected.

Lane Keeping System

The lane keeping system provides the driver with a lane keeping alert when unintentional drifting outside of the lane is detected. The IPC provides a lane keeping display of the vehicle in the middle of a lane with right and left lane markers to indicate the vehicle position with relation to the lane markings as well as overlay or pop-up messages to alert the driver when they are drifting out of the lane. The lane markers change color to indicate the condition associated with a specific condition and action or warning as controlled by the lane keeping system. The IPC also provides a lane keeping system message center off indicator to inform the driver that the lane keeping system is turned off. When the lane keeping system is turned off, the IPC turns on the lane keeping system RTT indicator and turns off the lane keeping system display.

Odometer

The IPC monitors the odometer count input from the PCM and commands the odometer with a digital display in the message center.

Outside Air Temperature

The Outside Air Temperature (OAT) sensor is located in the driver side mirror, and hardwired to the PCM through separate input and return circuits. The PCM provides a reference voltage to the Outside Air Temperature (OAT) sensor and monitors the change in voltage resulting from changes in resistance as determined by outside air temperature.

The PCM sends the ambient air temperature data to the HVAC module where the temperature data is filtered. The HVAC module sends the filtered outside air temperature data to the IPC to display the outside air temperature.

The HVAC module is programmed to update the messaged outside temperature data at different rates depending on several criteria to prevent false temperature displays due to a condition known as heat soaking. Heat soaking is where the outside air temperature is hotter in the location of the Outside Air Temperature (OAT) sensor than the actual outside air temperature.

The outside air temperature display update strategy requires a starting temperature to update from. This starting temperature is controlled based on the length of time the engine is off and the engine temperature. When the engine has been off for longer than 4 hours, the update strategy begins with the unfiltered ambient air temperature input to the PCM. If the engine has been off for less than 4 hours, and the engine coolant temperature is less than 30°C (86°F), the update strategy begins with the filtered ambient air temperature equal to the unfiltered ambient air temperature. If the engine has been off for less than 4 hours, and the engine coolant temperature is greater than 30°C (86°F), the update strategy begins at the stored previous outside air temperature value.

When the sensed outside temperature rises and the vehicle speed is above 32 km/h (21 mph), the outside air temperature display updates after approximately 90 seconds. As the vehicle speed increases, the outside air temperature display updates at a faster rate that is proportional to the increase in vehicle speed. Once the vehicle speed exceeds 80 km/h (50 mph), the display updates without any delay. If the vehicle speed drops below 32 km/h (21 mph), the update delays reset. When the sensed outside temperature drops, the display updates more quickly following the drop experienced by the Outside Air Temperature (OAT) sensor.