System Operation
System Diagram
Network Message Chart
Module Network Input Messages -- IPC
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist status | PAM | Input used to display the active park assist function messages. |
| Adaptive cruise control/collision avoidance sensor blocked | C-CM | Input used to display the radar sensor blocked warning message for adaptive cruise control and forward collision warning messages. |
| Adaptive cruise control monitor error | BCM | Input used to display the adaptive cruise control system fault message. |
| Adaptive cruise control request denied | C-CM | Input used to control the adaptive cruise control message center indicator and the adaptive cruise control message center message displays. |
| Adaptive cruise control service required | C-CM | Input used to provide the adaptive cruise control system malfunction warning message. |
| Adaptive cruise control message display | C-CM | Used for adaptive cruise control messages. |
| Adaptive headlamp failure message | HCM | Input used to control the check adaptive headlamps message display. |
| AWD lock status | PCM | Input used for the AWD message display. Input used for the AWD control of the powertrain malfunction (wrench) indicator. |
| AWD message display request | PCM | Input used for the AWD message display. |
| Brake fluid level low | BCM | Brake fluid level status for displaying the low brake fluid level warning message. |
| Brake pedal applied | PCM | Input used for the not in park message display. |
| Brake warning indicator request | BCM | Input used for parking brake applied message. |
| Charging system status | PCM | Provides the charging system indication request to control the charging system message center warning indicator and the load shed message display. |
| Collision mitigation by braking monitor error | BCM | Input used to display the forward collision system fault message. |
| Compass display data (touchscreen audio) | APIM | Provides compass heading data for the compass display. |
| Cross traffic information | SOD-L and SOD-R | Input used to provide cross traffic warning messages. |
| Cruise control set speed | PCM | Input used for adaptive cruise control message center indicator and displays. |
| Cruise control status | PCM | Input used for adaptive cruise control message center indicator and message displays. |
| Cruise control override | PCM | Input used for adaptive cruise control message center indicator and message displays. |
| Driver alert warning | IPM-A | Input used to control the level of alertness message center displays. |
| Drivers door ajar status | BCM | Provides the door ajar request to display the driver door ajar message, illuminate the door ajar message center warning indicator and display the not in park message on vehicles with IA. |
| Electronic Power Assist Steering (EPAS) failure | PSCM | Input required for the service power steering message. |
| Engine overheat failsafe mode | PCM | Engine temperature data used for the engine over-temperature message center warning indicator. |
| Engine coolant temperature fault reporting | PCM | Input used to determine the quality of the engine temperature data input for the engine over-temperature message center warning indicator. |
| Engine oil life percent | PCM | Used for the oil life display. |
| Engine rpm | PCM | Input used for the low oil pressure message center warning indicator. Input used to control the DTE display. |
| Engine service required | PCM | Input used for the ETC component of the powertrain malfunction (wrench) indicator. |
| Engine status | PCM | Input used to display the engine on warning message and the Average Fuel Economy (AFE)/DTE display. |
| Forward collision warning system malfunction | C-CM | Input used to display the forward collision system not available message resulting from a system malfunction. |
| Forward collision warning system message display | C-CM | Input used to display the forward collision system warning message. |
| Front camera status | IPM-A | Input used to control the front camera fault message display. |
| Fuel/alcohol percent | PCM | Input used to calculate the DTE display. |
| Fuel fill inlet | PCM | Input required for the display of the fuel fill inlet message. |
| Fuel flow | PCM | Used for average fuel flow, DTE and trip fuel displays. |
| GPS compass direction (without touchscreen audio) | GPSM | Provides compass heading data (converted from MS-CAN to HS-CAN in the BCM) for the compass display. |
| Hands off warning | IPM-A | Input used to control the lane keeping aid (hands off) warning message and lane departure warning system unavailable message. |
| Ignition status | BCM | Ignition RUN, START and accessory states required for the IPC operating modes and fault reporting. |
| Immobilize indicator | BCM | Input used to provide the starting system fault message for the PATS. |
| Intelligent access system status | BCM | Input used to control the warning messages displayed for IA. |
| Lane departure switch status | IPM-A | Input used to control the on/off status of the lane departure warning system display. |
| Lane departure warning status | IPM-A | Input used to control the lane departure warning system display. |
| Left rear door ajar status | BCM | Provides the door ajar request to display the left rear door ajar message and illuminate the door ajar message center warning indicator. |
| Liftgate/luggage compartment lid ajar status | BCM | Provides the door ajar request to display the luggage compartment lid ajar message and illuminate the luggage compartment lid ajar message center warning indicator. |
| MyKey® key display | BCM | Input used to provide the MyKey® key information for display messages related to MyKey® key programming and setup. |
| Odometer count | PCM | Rolling count data used for the odometer and trip odometer. Input used to control the DTE display. |
| OCS object entrapped message request | OCSM | Input used to display the remove objects near the passenger seat warning message. |
| Oil pressure warning | PCM | Provides the oil pressure switch status to control the low oil pressure message center warning indicator. |
| Outside air temperature | BCM | Combined messages for outside air temperature status and outside air temperature data fault reporting for the outside air temperature display. |
| Park brake chime request | BCM | Input used to control the parking brake warning message. |
| Passenger door ajar status | BCM | Provides the door ajar request to display the passenger door ajar message and illuminate the door ajar message center warning indicator. |
| Passenger rear door ajar status | BCM | Provides the door ajar request to display the right rear door ajar message and illuminate the door ajar message center warning indicator. |
| Passive entry/passive start system status | BCM | Input required for the display of the IA messages. |
| Police auxiliary switch display | GFM | Input used to control the auxiliary switch display (police package only). |
| Powertrain cooling warning request | PCM | Input used to display the powertrain cooling message display. |
| Stability-traction control warning request | ABS module | Input used to control the service AdvanceTrac® and traction control off warning displays. |
| Steering wheel switch multimedia data (cursor and OK button) | SCCM | Message center switch input from the LH steering wheel switch. |
| Tire pressure status | BCM | Inputs used to provide system fault and low tire warning messages. |
| Trailer sway event in progress | ABS module | Provides trailer sway status request for display of the trailer sway warning message. |
| Transmission display mode actual | PCM | Input used for the not in park message display. |
| Transmission service required | PCM | Input used for the transmission component of the powertrain malfunction (wrench) indicator. |
| Transport mode | BCM | Input used to indicate whether the vehicle is set in factory mode or transport mode to display the appropriate message and power down items such as the PRNDL at key off to conserve the battery. Input used to control the DTE display. |
| Vehicle speed | PCM | Input used for the digital speedometer and the not in park message display. Input used to control the DTE display. |
| Vehicle speed fault reporting | PCM | Input used to determines the quality of the vehicle speed data input for the not in park message display. |
Average Fuel Economy Display
Average Fuel Economy (AFE) is calculated using the following messaged inputs:
- Fuel flow volume display
- Odometer count
- Vehicle speed
- Engine rpm data
- Engine status
All messaged inputs are sent to the IPC by the PCM.
Compass Display (Except Police And Without Touchscreen Audio)
The vehicle heading is displayed in the message center as a 1 or 2 character display that indicates the current direction of the vehicle (N, NE, E, SE, S, SW, W, or NW). On vehicles equipped with the optional dual screen IPC, the compass can be displayed as a virtual compass along with the 1 or 2 character display. The compass signal originates with the GPSM. The GPSM sends the GPS compass direction message to the IPC through (gateway) the BCM to the IPC. No calibration or zone adjustment is available, as the compass heading is based on the GPS signal. Refer to the appropriate Information and Entertainment System article for the procedure.
Compass Display (With Touchscreen Audio)
The vehicle heading is displayed in the message center as a 1 or 2 character display that indicates the current direction of the vehicle (N, NE, E, SE, S, SW, W, or NW). On vehicles equipped with the optional dual screen IPC, the compass can be displayed as a virtual compass along with the 1 or 2 character display. The compass signal originates with the APIM and is transmitted to the IPC through the I-CAN.
Digital Speedometer
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 analog speedometer. On non-police vehicles, the IPC utilizes software that modifies the display to account for differences between the speedometer gauge indication and the digital display resulting from built in biasing of the indication and tolerances in speedometer stepper motor/needle movement. On police vehicles, the digital speedometer uses the unfiltered and unbiased vehicle speed input from the PCM to display the digital speed.
DTE Display
The DTE is calculated in the IPC using the Running Average Fuel Economy (RAFE), which is the fuel economy over approximately the last 480 km (300 miles), and the fuel level input from the fuel sender(s) to determine how many miles the vehicle can be driven based on the remaining fuel in the fuel tank. If the fuel economy is relatively constant, the DTE can be off over a 50 mile range by -24% to +38%. The DTE display and the fuel gauge both use the fuel level input from the fuel tank to provide their respective functions. If the fuel gauge doesn't function correctly, both the fuel gauge and the DTE display are affected.
The DTE defaults to around 21 mpg when the battery is initially connected and changes based on driving habits and conditions. Generally, the driver should be getting somewhere between 13-27 mpg.
Since the DTE is calculated and averaged over a longer period of time (480 km [300 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 (partial refueling)
- To better illustrate the affects of how driving conditions can affect DTE, refer to the 2 following examples. The first example below illustrates how the following observations are normal and expected since the low fuel reminder is triggered from a fixed distance to empty.
- If while driving, the low fuel reminder (low fuel indicator and low fuel warning message) displays when the DTE equals 80 km (50 miles) and the fuel level is 1/8th of a tank and the driver adds 11 L (3 gallons) of fuel, the new DTE may become 125 km (98 miles). After continued highway driving, the low fuel reminder may now display when the fuel level is less than 1/8 tank.
- The second example (below) illustrates what occurs when idling on an incline. In this example, the customer should be made aware of how the condition will correct after a few minutes of idling on a level surface.
- If the customer stops and parks the vehicle on an incline in a driveway, then in the morning remote starts the vehicle, allowing the engine to idle for 10 minutes, the DTE may now equal 105 km (55 miles). As the customer drives, the low fuel reminder displays when the DTE equals 80 km (50 miles). Finally, after 5 more minutes of driving, the DTE is back to 80 km (96 miles) and the low fuel reminder extinguishes.
The IPC uses the following network messages to control the DTE /Average Fuel Economy (AFE).
- Engine rpm data
- Fuel alcohol percent
- Fuel flow volume display
- Odometer count
- Transport mode
- Vehicle speed
The IPC receives the engine rpm data, fuel alcohol percent, fuel flow volume display, odometer count and vehicle speed messages from the PCM. The IPC receives the transport mode message from the BCM.
Keypad Factory Code Display
The message center can display the original keypad factory code when requested. Refer to Handles, Locks, Latches and Entry Systems - Without Intelligent Access or Handles, Locks, Latches and Entry Systems - With Intelligent Access Description and Operation (D) for the procedure to display the keypad factory code.
Oil Change Minder
The message center provides an oil change minder to inform the driver that an oil change is required. The duration of the interval between oil changes is calculated in the PCM and varies due to driving conditions. The PCM assumes a base mileage of 16, 090 km (10, 000 mi) or 1 year for normal driving. However, this number is adjusted down for conditions such as high engine temperature, high engine rpm, use of flex fuel and possibly low oil level. The PCM calculates and provides the engine oil life percent message to the IPC.
When the remaining oil life is between 1%-5%, the message center displays the change oil soon message. When the remaining oil life is at 0%, the message center displays the oil change required message.
Outside Air Temperature Display
The AAT sensor is hardwired to the PCM through separate input and return circuits. The PCM provides a reference voltage to the AAT sensor and monitors the change in voltage resulting from changes in resistance as determined by outside air temperature. The PCM messages the outside air temperature data to the HVAC module through the BCM. The HVAC module filters the temperature data and sends the updated temperature status back to the BCM. The BCM in turn messages the outside air temperature in degrees Celsius (metric) to the IPC. When the Fahrenheit (English) display is selected by the driver, the IPC converts the Celsius to Fahrenheit and displays the temperature in the message center.
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 air temperature in the location of the AAT sensor is hotter than the actual outside air temperature.
When the sensed outside temperature rises, the display updates slowly at varying rates based on vehicle speed. When the sensed outside temperature drops, the display updates more quickly following the drop experienced by the AAT sensor.
Auxiliary Switch Menu Display -- Police Package
The IPC receives the auxiliary switch status from the GFM. When an auxiliary switch is turned on, the GFM sends the police auxiliary switch display message to the IPC, which displays a switch image in the message center, changing the display from gray to blue to indicate the status.
Cruise Control Message Center Indicator
The IPC receives the cruise control status message from the PCM. When the cruise control switch is placed in the ON position, the PCM sends the IPC a standby mode request through the cruise control status message and the IPC illuminates the cruise control indicator in gray. When the cruise control is engaged, the PCM sends a cruise control on request through the cruise control status message to the IPC and the IPC changes the cruise control indicator illumination from gray to green.
Charging System Message Center Indicator
The charging system message center warning indicator is controlled by the IPC based upon data received from the BCM. The BCM receives the charging system status from the PCM. When a fault is detected in the charging system, the BCM sends the IPC a charging system status message to illuminate the charging system message center warning indicator. Refer to Charging System .
Door/Luggage Compartment Lid Ajar Message Center Indicator
The IPC receives the door ajar status for the LF, RF, LR, and luggage compartment lid ajar switches from the BCM. When the IPC receives a driver door, passenger door, left rear door, right rear door or luggage compartment lid ajar status message from the BCM that one or more doors or the luggage compartment lid are open or ajar, the IPC illuminates the appropriate door/luggage compartment lid ajar message center warning indicator.
Engine Over-Temperature Message Center Warning Indicator
The PCM uses the CHT sensor to measure the engine temperature. The IPC receives the engine coolant temperature data message from the PCM. The IPC requires 2 basic messaged inputs to control the engine over-temperature message center warning indicator. The first is the engine overheat failsafe mode message. The second is an engine coolant temperature fault reporting message. When the engine temperature reaches 121 deg. C (250 deg. F) and when the PCM sends the engine overheat failsafe mode message and does not receive the engine coolant temperature fault reporting message, the IPC illuminates the engine over-temperature message center warning indicator.
Grade Assist Message Center Indicator
The IPC receives the grade assist on/off status from the PCM. When the grade assist function is selected off, the PCM sends the transmission shift mode message to the IPC to illuminate the grade assist message center indicator.
Low Fuel Message Center Indicator
The IPC uses the average fuel level to determine when to turn on the low fuel message center indicator. On single sender L-shaped fuel tank configurations, the IPC uses the input from the fuel pump assembly. On dual sender saddle-type fuel tank configurations, the IPC uses an average of the combined fuel level inputs.
When an administrator key is in use, the low fuel message center indicator turns on when the fuel level is approximately 1/8 tank. When a MyKey® programmed key is in use, the low fuel message center indicator is turned on when the fuel level is approximately 3/16 tank.
Low Oil Pressure Message Center Warning Indicator
The engine oil pressure switch is hardwired to the PCM. The PCM provides the oil pressure warning message and engine rpm message to the IPC over the HS-CAN communication bus. The IPC requires engine rpm above 500 rpm before the message center displays the low oil pressure message center indicator.
The PCM provides a reference voltage to the engine oil pressure switch when the ignition is in RUN. With the engine running and low or no oil pressure, the engine oil pressure switch remains open. The PCM detects no change in the reference voltage and provides the IPC a request to illuminate the low oil pressure warning indicator. With the engine running and sufficient oil pressure, the engine oil pressure switch closes, pulling the reference voltage low. The PCM detects the low reference voltage and provides the IPC the oil pressure warning message to turn off the low oil pressure warning indicator.
The engine oil pressure switch is hardwired to the PCM. The IPC receives the oil pressure warning message and the engine rpm message from the PCM. With the KOEO, the IPC does not display the low oil pressure message center warning indicator until the engine is started and it receives the engine rpm message.
Low Washer Fluid Message Center Indicator
The low washer fluid level switch is hardwired to the IPC through a single signal circuit and is grounded through a separate ground circuit. The IPC provides a reference voltage to the washer fluid level switch. When the washer fluid is low, the washer fluid level switch closes to ground, pulling the reference voltage low. When the IPC detects the washer fluid input pulled low and illuminates the low washer fluid level message center warning indicator.
Powertrain Malfunction (Wrench) Message Center Indicator
The IPC receives the ETC, AWD and the transmission status from the PCM.
When a fault condition exists in the ETC system, the PCM provides the IPC with the engine service required message to illuminate the powertrain malfunction (wrench) message center warning indicator.
When a fault condition exists in the transmission, the PCM provides the IPC with the transmission service required message to illuminate the powertrain malfunction (wrench) message center warning indicator.
When a fault condition exists in the AWD system, the PCM provides the IPC with the AWD lock status message to illuminate the powertrain malfunction (wrench) message center warning indicator.
Adaptive Cruise Control Display
The IPC receives the adaptive cruise control display message request from the C-CM.
When a fault exists in the adaptive cruise control system or for a specific system status, the C-CM sends the IPC a message to display the appropriate message. When the driver has selected a specific speed or gap setting, the C-CM sends the IPC a message to display the driver selected setting. Refer to Cruise Control - Adaptive .
TPMS Message Display
The IPC receives the tire pressure status message from the BCM. When the tires are in training mode, a fault condition exists or a low tire pressure condition exists, the IPC displays a TPMS message to indicate the system status.
Check Fuel Fill Message Display
The PCM monitors the fuel tank evaporative emission system for significant leaks that occur following refueling of the vehicle. Once the PCM detects a fuel vapor leak, the PCM sends a fuel fill inlet message to the IPC to display the CHECK FUEL FILL INLET message. The PCM only sets a fault code following a successful cruise test, which is initiated when the vehicle is driven at a steady speed above 64 km/h (40 mph) for a duration of approximately 4-5 minutes. If the PCM is unable to successfully run the cruise test, the IPC does not receive the fuel fill inlet message and the CHECK FUEL FILL INLET message remains off.
Engine Idle Shut Down Message Display (Push Button Start)
The message center provides messages to indicate the status of the engine idle shut down. If there is no driver interaction with the vehicle for 30 minutes with the engine idling, the message center displays a warning that the engine is about to be shut down. The driver then can override the shut down for the current ignition cycle through the message center if desired. The IPC provides the engine idle system disable message and receives the engine idle shut down system status from the BCM.
Lane Departure Warning System Display
The departure warning system display is controlled by data sent to the IPC from the IPM-A. When the lane departure warning system is enabled, the IPC displays an overhead view of a vehicle inside of lane markers in the LH message center screen next to the fuel gauge.
The lane departure warning system displays right and left lane markers and arrows that change color to indicate the vehicle's position within the roadway lane markers. The lane departure warning system can be turned off by the driver. When the lane departure warning system is turned off, the lane departure warning system display is turned off in the LHIPC display screen. Refer to Lane Keeping System for a complete description of the lane departure warning system and the associated lane marker color changes/warnings.
Service AdvanceTrac® Message Display
The IPC receives the stability-traction control warning request from the ABS module. When a fault exists in the stabilty-traction control system, the ABS module sends the stability-traction control warning request to the IPC to display the service advancetrac message and sound the service advancetrac warning chime.
Shift To Park Message Display
The IPC uses inputs from the PCM and BCM to control the shift to park message display. The inputs from the PCM are the transmission display mode actual, the brake pedal applied, the vehicle speed and the vehicle speed fault reporting. The messages from the BCM are the driver's door ajar status and ignition status.
When the selector lever is out of the PARK (P) position with the vehicle stopped (no vehicle speed input) and the brake pedal not applied, the ignition is off and the driver door is ajar, the IPC displays the shift to park message in the message center.