Instrument Panel Cluster (IPC) - System Operation and Component Description: Gauges
System Diagram - Gauges
Gas
Hybrid
Network Message Chart - Gauges, Gas
Module Network Input Messages - IPC
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| AWD wheel lock display | AWD module | Input used for the AWD gauge. |
| Engine coolant temperature data | PCM | Input used for the analog and virtual temperature gauge indication. |
| Engine overheat indication request | PCM | Input used to send the analog and virtual temperature gauge pointer to full hot. |
| Engine rpm data | PCM | Input used for analog and virtual tachometer indication. |
| Fuel level display | PCM | Input used to send the fuel level gauge pointer to the appropriate calculated fuel level. |
| Ignition status | BCM | Ignition RUN, START and accessory states required for the IPC operating modes and fault reporting. |
| Vehicle speed | PCM | Vehicle speed data used for the speedometer indication. |
Module Network Input Messages - PCM
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Fuel level data | IPC | Fuel level data obtained from the fuel pump and sender unit (hardwired to the IPC) and sent to the PCM to calculate the actual fuel level. |
Network Message Chart - Gauges, Hybrid
Module Network Input Messages - IPC
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| AWD wheel lock display | AWD module | Input used for the AWD gauge. |
| Battery state of charge data (except China) | BECM | Input used to display the remaining available high voltage battery charge. |
| Engine coolant temperature data | PCM | Input used for the analog and virtual temperature gauge indication. |
| Engine overheat indication request | PCM | Input used to send the analog and virtual temperature gauge pointer to full hot. |
| Engine rpm data | PCM | Input used for analog and virtual tachometer indication. |
| Fuel level display | PCM | Input used to send the fuel level gauge pointer to the appropriate calculated fuel level. |
| Heater core temperature | PCM | Input used for the analog and virtual temperature gauge. |
| Ignition status | BCM | Ignition RUN, START and accessory states required for the IPC operating modes and fault reporting. |
| Vehicle speed | PCM | Vehicle speed data used for the speedometer indication. |
Module Network Input Messages - PCM
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Fuel level data | IPC | Fuel level data obtained from the fuel pump and sender unit (hardwired to the IPC) and sent to the PCM to calculate the actual fuel level. |
AWD Gauge
The AWD gauge displays the level of power applied to each wheel independently. The AWD system is almost always active and is transferring torque whenever the vehicle is accelerating, boosting output when wheels are slipping and shutting off on the highway to conserve fuel. The IPC receives the AWD wheel lock display message from the GWM over the HS-CAN3. The GWM receives the AWD wheel lock display message from the AWD module over the HS-CAN1
As power is applied to the wheels, the area directly in front (front wheels) or rear (rear wheels) of each displayed wheel begins to fill in. The lowest power displayed is the closest to the wheel. As the amount of power sent to the wheels increases, the area fills in either forward (front wheels) or rearward (rear wheels) of the wheels.
Fuel Gauge
The IPC sends a reference voltage to the fuel level sender. As the fuel level changes, a float actuates the variable resistor fuel level sender, raising or lowering the fuel level signal voltage. The IPC monitors the changes in voltage from the fuel level sender and sends a fuel level data message to the PCM through the GWM to calculate the fuel level.
The PCM calculates the fuel level based on current fuel in the fuel tank and the tank size. The PCM sends the fuel level display message to the IPC through the GWM to activate the needle in the fuel gauge.
After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) can range from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.
The IPC uses 4 different operating modes to calculate the fuel level:
- Anti-slosh (default mode).
- Key OFF fueling.
- Key ON fueling.
- Recovery.
The default fuel gauge mode is called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sensor readings caused by fuel moving around in the tank), the fuel gauge takes approximately 40 minutes to go from empty (E) to full (F).
The key off fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions to be met:
- The ignition must be in the OFF mode when refueling the vehicle.
- At least 10% of the vehicle's fuel capacity must be added to the fuel tank.
- The IPC must receive a valid ignition ON fuel sensor reading within one second of the ignition being put into the RUN mode. The key ON sample readings are considered valid if the fuel sensor reading is between 10 ohms ± 2 ohms and 180 ohms ± 4 ohms.
If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.
The key ON fueling mode (approximately 60 seconds to read empty [E] to full [F]) requires the following conditions be met:
- The transmission is in P or N.
- The ignition is in the RUN mode.
- At least 10% of the vehicle's fuel capacity must be added to the fuel tank.
In key ON fueling mode, a 30-second timer activates after the transmission is put into the P or N position. When the 30-second time has elapsed and at least 9% of the vehicle's fuel capacity has been added, the fuel gauge response time is 60 seconds to read from empty (E) to full (F). When the transmission is shifted out of P or N, the fuel gauge strategy reverts to the anti-slosh mode. The key ON fueling mode prevents slow to read full events from happening if the customer refuels the vehicle with the ignition in the RUN mode.
Speedometer
The IPC receives the vehicle speed data from the GWM over the HS-CAN3. The GWM receives the vehicle speed message from the PCM over the HS-CAN1.
The PCM uses tire size stored in the vehicle configuration file along with wheel speed inputs to generate a vehicle speed signal. The PCM receives the wheel speed data from the ABS module.
The IPC provides a tolerance that allows the speed indication to display between 3% below and 7% above the actual vehicle speed. This means that with an actual vehicle speed of 97 km/h (60 mph), the speedometer can indicate between 94-103 km/h (58-64 mph). Incorrect tire size or tire size configuration could potentially affect the speedometer accuracy.
Tachometer
The IPC receives the engine rpm data message from the GWM over the HS-CAN3. The GWM receives the engine rpm data message from the PCM over the HS-CAN1.
Temperature Gauge
The IPC uses 2 messages to control the temperature gauge. The first is the engine coolant temperature data, which provides the current coolant temperature input to the PCM. The second message is the engine overheat indication request, which is sent by the PCM to the IPC when an overheating condition exists. When the IPC receives the engine overheat indication request message, the IPC sends the temperature gauge to full hot and turns on the over-temperature warning indicator.
The IPC receives both temperature gauge input messages from the GWM over the HS-CAN3. The GWM receives the engine coolant temperature data and the engine overheat indication request messages from the PCM over the HS-CAN1.