The indicators are illuminated by one of the following components:
| • | The instrument panel cluster (IPC) microprocessor by discrete inputs to the IPC. |
| • | The other modules via the class 2 serial data line. |
Messages may be displayed on the driver message center when some indicators are illuminated. Some IPC indicators may be illuminated by several different conditions.
AIR BAG (Red)
The AIR BAG indicator is illuminated by the IPC whenever the inflatable restraint sensing and diagnostic module (SDM) sends a class 2 message requesting information, via the class 2 serial data line. The IPC flashes the indicator 7 times during the bulb check, and illuminates the indicator until a class 2 message is received from the SDM. The AIR BAG indicator is illuminated by the IPC whenever the IPC detects a loss of communications with the SDM.
ANTI-LOCK (Yellow)
The ANTI-LOCK indicator has 3 different methods of illumination:
| • | The indicator is illuminated whenever the IPC detects a loss of communication with the electronic brake and traction control module (EBTCM) and the state of CKT 852 (WHT) is high (EBTCM disconnected). |
| • | The indicator is illuminated by the IPC whenever the EBTCM sends a class 2 message requesting illumination, via the class 2 serial data line. |
| • | The indicator is illuminated by the IPC during bulb check. |
Battery (ISO Symbol) (Red)
The battery indicator is illuminated by the IPC when the IPC detects an alternator L-terminal malfunction on CKT 225 (RED) (DTC B1911). The IPC illuminates the indicator during bulb check.
BRAKE (Red)
The BRAKE indicator is illuminated by the IPC for one of the following reasons:
| • | When the IPC detects a low (ground) on CKT 849 (PNK), the brake fluid level switch is closed (low fluid condition). |
| • | When the EBTCM sends a class 2 message requesting illumination via the class 2 serial data line, the IPC displays the CHECK BRAKE FLUID message on the driver message center. |
| • | When the IPC detects that CKT 849 (PNK) is above the normal 4 V level, an open exists in CKT 849. The IPC displays the SERVICE BRAKE FLUID SWITCH message on the driver message center. |
| • | The BRAKE indicator illuminates during bulb check. |
Engine Coolant Temperature (ISO Symbol) (Red)
The engine coolant temperature indicator is illuminated by the IPC based on the coolant temperature information from the powertrain control module (PCM), or when the PCM sends a class 2 message requesting illumination via the class 2 serial data line. The IPC displays one of the following messages on the driver message center:
| • | ENGINE COOLANT HOT, IDLE ENGINE |
| • | STOP ENGINE, ENGINE OVERHEATED |
The IPC illuminates the indicator during bulb check.
Engine Oil Pressure (ISO Symbol) (Red)
The engine oil pressure indicator is illuminated by the IPC whenever the PCM sends a class 2 message requesting illumination, via the class 2 serial data line. The IPC illuminates the indicator during bulb check.
Fasten Safety Belt (Red)
The fasten safety belt indicator is illuminated by the IPC whenever the Body Control Module (PZM) sends a class 2 message requesting illumination, via the class 2 serial data line. The IPC illuminates the indicator during bulb check.
Hazard (Red)
The hazard indicator is illuminated by the IPC when the IPC simultaneously detects a high (voltage) on CKT 14 (LT BLU) and CKT 15 (DK BLU). When the hazard switch is closed, CKT 14 (LT BLU) and CKT 15 (DK BLU) are supplied voltage from the HAZARD fuse through the hazard flasher. The IPC illuminates the indicator during bulb check.
High Beam (Blue)
The high beam indicator is illuminated by the IPC when the PZM sends a class 2 message indicating that the high beams are activated. The IPC illuminates the indicator during the segment check in the vehicle diagnostic mode.
Left Turn (Green)
The left turn indicator is illuminated by the IPC when the IPC detects a high (voltage) on CKT 14 (LT BLU). When the left turn switch is closed, CKT 14 (LT BLU) is supplied voltage from the TURN fuse through the turn flasher module. The IPC illuminates the indicator during the segment check in the vehicle diagnostic mode.
PARK BRAKE (Red)
The PARK BRAKE indicator is illuminated by the IPC when the IPC detects a low (ground) on CKT 1134 (LT BLU). The park brake switch is closed. The IPC illuminates the indicator during bulb check.
Right Turn (Green)
The right turn indicator is illuminated by the IPC whenever the IPC detects a high (voltage) on CKT 15 (DK BLU). When the right turn switch is closed, CKT 15 (DK BLU) is supplied voltage from the TURN fuse through the turn flasher module. The IPC illuminates the indicator during the segment check in the vehicle diagnostic mode.
Security (Yellow)
The security indicator is illuminated by the IPC whenever the Body Control Module (PZM) sends a class 2 message requesting illumination via the class 2 serial data line. The IPC illuminates the indicator during bulb check.
SERVICE ENGINE SOON (MIL) (Yellow)
The SERVICE ENGINE SOON (MIL) indicator is illuminated by the PCM. The PCM provides a ground for the indicator illumination via CKT 419 from the IPC connector C2 terminal A3 to the PCM connector C2 terminal 26. The PCM illuminates the indicator during bulb check.
Traction Control (Yellow)
The TRACTION CONTROL indicator is illuminated by the IPC whenever the EBTCM sends a class 2 message requesting illumination via the class 2 serial data line. The IPC illuminates the indicator if a loss of communications is detected with the EBTCM. The IPC illuminates the indicator during bulb check.
Dynamic Parameters
The IPC blanks the data portion of the following parameter displays prior to the receipt of valid data:
| • | The instantaneous fuel economy |
| • | The average fuel economy |
| • | The fuel level |
| • | The outside air temperature |
| • | The coolant temperature |
| • | The oil life index |
| • | The range |
The digital IPC displays all dashes (except the vehicle speed and the odometers) if the serial data line communications of all vehicle modules are determined to be lost. Selective dashing of the displays is indicative of an inability to communicate with only certain vehicle modules on the class 2 serial data line.
The analog IPC dashes all of the parameters. The analog IPC does not control the fuel level and the coolant temperature gauge if the serial data line communication of all microprocessors is determined to be lost. Selective dashing or inoperative gauges may indicate an inability to communicate with only certain microprocessors on the class 2 serial data line.
Fuel Data Center (Digital)
The fuel data center provides a numeric readout of the following data:
| • | Range |
| • | Instant fuel economy |
| • | Average fuel economy |
Calculations are made by the IPC using the odometer information and the fuel information sent via the class 2 serial data line.
The INST and AVG buttons are used in order to toggle between the average and the instant fuel economy displays.
Range
The range displayed is an estimate of the expected remaining driving distance with the current fuel level. The vehicle driving range is based on the fuel remaining in the tank and the fuel economy over the last 40 km (25 mi). Since the calculated range parameter is an estimated value, the displayed value and the actual vehicle range may vary. When the calculated range parameter falls below 65 km (40 mi), the range displayed is LO. The range parameter is calculated by the IPC using the following formula:
(Estimated Range) = (Distance Traveled) / (Fuel Used) x (Scale Factor) x (Filtered Fuel in Tank)
This calculation may not be reset by the driver. The data used in order to calculate the range parameter is lost if a battery disconnect occurs. The range display contains dashes if the IPC is unable to communicate with the PCM or PZM via the class 2 serial data line.
Instant Fuel Economy
The instant fuel economy display is based on the previous few seconds of vehicle operation. The instantaneous fuel economy (IFE) parameter is calculated by the IPC using the following formula:
(IFE) = (Distance) / (Fuel Used) x (Scale Factor)
The distance is determined from the discrete vehicle speed input to the IPC and the fuel data is received from the PCM.
This calculation may not be reset by the driver. The data used in order to calculate the IFE parameter is lost if a battery disconnect occurs. The message contains dashes if the IPC is unable to communicate with the PCM or PZM via the class 2 serial data line.
Average Fuel Economy
The AVG display is in liters per 100 kilometers (L/100 km) or miles per gallons (MPG) obtained since the last parameter reset. The average fuel economy parameter is calculated by the IPC using the following formula:
(Average Fuel Economy) = (Trip Distance) / (Trip Fuel Used) x (Scale Factor)
In order to reset the display, press the AVG (digital) button, then press the RESET (digital) button.
The AVG display contains dashes if the IPC is unable to communicate with the PCM via the class 2 serial data line.
Dashes Displayed in Fuel Data Center
If a malfunction occurs in the serial data communications from the IPC to the PCM, dashes are displayed in the fuel data center display. Diagnose this symptom by retrieving and diagnosing the PCM or IPC serial data communication DTCs.
IPC Functions
Exterior Lighting
The exterior lighting performs the following functions:
| • | For the low beam operation, when the headlamp switch is enabled, the IPC connector C3 terminal D6 is grounded through the headlamp switch. In response to this input, the IPC sends a request via the class 2 serial data line to the PZM in order to activate the low beam headlamps. The PZM sends the appropriate commands in order to activate the low beams. Refer to Headlamps Schematics in Lighting Systems. |
| • | For the high beam operation, when the multifunction lever is pulled inward, the headlamp dimmer switch closes. This action sends an input to the IPC connector C2 terminal B8. In response to this input, the IPC sends a request via the class 2 serial data line to the PZM in order to activate the high beam headlamps. The PZM performs the appropriate commands in order to activate the high beams. Refer to Headlamps Schematics in Lighting Systems. |
| • | For the twilight sentinel, when the twilight sentinel is enabled, the IPC connector C3 terminal D8 is not grounded through the headlamp switch. When the ignition switch is in the RUN position, the twilight photocell indicates darkness, and the twilight switch is enabled, the IPC sends a request via the class 2 serial data line to the PZM in order to activate the low beam headlamps. The PZM sends the appropriate commands in order to activate the low beams. Refer to Body Control Module Schematics in Body Control Systems. |
| • | For the twilight delay, the IPC monitors the twilight delay input at IPC connector C3 terminal D12. As the twilight delay switch is moved from MIN to MAX, the voltage at the terminal D12 increases. The IPC adjusts the twilight delay in 10 second intervals from 3-180 seconds in response to the voltage level at the twilight delay input. If the twilight sentinel switch is turned OFF during the delay period, the headlamps and the park lamps turn OFF immediately. The PZM sends the appropriate commands in order to deactivate the exterior beams. Refer to Body Control Module Schematics in Body Control Systems. |
Fuel Door Release
When the fuel door release is pressed, the IPC connector C3 terminal C3 (CKT 136 (TAN)) is connected to ground. The IPC detects this low (ground) input and sends a message to the PZM via the class 2 serial data line. The PZM sends the appropriate commands in order to activate the fuel door release solenoid. Refer to Fuel Door Release Schematics in Body Rear End.
Wiper Activated Headlamps
The wiper activated headlamps function allows the headlamps and the park lamps to be activated by the windshield wiper switch. When the ignition switch is in the RUN position, the twilight sentinel is enabled, and the IPC determines that the windshield wiper switch has been activated for approximately 20 seconds, the headlamps turn ON. The IPC sends a message to the PZM in order to activate the headlamps and the park lamps via the class 2 serial data line. The wiper activated headlamps function overrides the daytimes running lamps if active.
Steering Wheel Controls
The IPC monitors the steering wheel control buttons at the IPC connector C2 terminal B11. The IPC interprets the button commands and issues the appropriate class 2 messages.
PASSKey® II
The IPC contains the software for controlling the PASSKey® II system. The IPC monitors the key-in-ignition (CKT 80 (LT GRN)) and the ignition key resistor (CKT 1073 (WHT/BLK)) inputs in order to determine how to control the starter enable (CKT 625 (YEL/BLK)) output. The IPC also sends a fuel enable message to the PCM via the class 2 serial data line.
Rear Compartment Lid Release
When the rear compartment lid release switch is pressed, the IPC connector C3 terminal D5 (CKT 1576 (TAN)) is connected to ground. The IPC detects this low (ground) input and sends a message to the PZM via the class 2 serial data line. The PZM sends the appropriate commands to activate the rear compartment lid release solenoid. Refer to Rear Compartment Lid Release Schematics in Body Rear End.
Starter Enable/Inhibit
The starter enable function allows the IPC to energize the starter enable relay when the correct ignition key is inserted into the ignition switch.
The starter inhibit function is designed in order to prevent the starter from being operated while the engine is running. When the engine is running, the PCM sends a message to the IPC via the class 2 serial data line. The IPC responds to this message by disabling the starter enable relay. The IPC performs this action by removing the ground from the starter relay output circuit.
Vehicle Interior Lamps: Dimming
The IPC controls all of the interior dimming functions. The IPC monitors the following components in order to determine when to activate the interior dimming functions:
| • | The ignition switch |
| • | The headlamp switch |
| • | The fog lamp switch |
| • | The twilight sentinel switch |
| • | The ambient light sensor |
The IPC controls all of the VF displays via class 2 messages. The IPC controls the incandescent lighting through the INC DIM 1 and the INC DIM 2 outputs. If the ambient light sensor is inoperative, the IPC defaults to a darkness condition. The IPC indicators may not be dimmed.
