Displays Test
Certain instrument panel cluster (IPC) features are tested when the ignition is turned on in order to verify that the features are working properly. The following indicators illuminate briefly at key up, unless otherwise noted:
| • | Air bag--Flashes 7 times |
| • | Charge indicator--Stays ON |
| • | Fasten safety belt--Flashes |
| • | Low oil pressure indicator |
| • | Malfunction indicator lamp (MIL)--Stays ON |
Indicators and Warning Messages
Refer to
Indicator/Warning Message Description and Operation
.
Clock
The radio sends current time to the instrument panel cluster (IPC) via class 2. The IPC receives a class 2 message from the radio indicating the time. The IPC analog clock, if equipped, zeroes itself to 12:00 during key up and then resets
to the current time via the class 2 message received from the radio.
Engine Coolant Temperature Gage
The engine control module (ECM) sends the coolant temperature to the body control module (BCM) via class 2. The instrument panel cluster (IPC) displays the engine coolant temperature, as determined by the BCM. The IPC receives a class 2 message
from the BCM indicating the engine coolant temperature. The engine coolant temperature gage, if equipped, defaults to 75°C (160°F) or below if:
| • | The ECM detects a malfunction in the engine coolant temperature sensor circuit. |
| • | The IPC detects a loss of class 2 communications with the BCM. |
| • | The BCM detects a loss of class 2 communications with the ECM. |
Refer to
Cooling System Description and Operation
in Engine Cooling for more information.
Odometer
The instrument panel cluster (IPC) displays the vehicle and trip mileage, as determined by the engine control module (ECM). The IPC calculates the vehicle mileage based on the speed pulses from the vehicle speed sensor (VSS) signal and calculating the
mileage for odometer displays. The odometer will display 'error' if an internal IPC memory failure is detected and DTC B1009 is set.
Speedometer
The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The ECM sends a 4,000 pulses per mile signal to the cluster discretely. The IPC calculates the vehicle speed using the time
difference between consecutive pulses. The speedometer will default to zero if the time duration since the last speed pulse is greater than or equal to 1 second.
Tachometer
The instrument panel cluster (IPC) receives a discrete input from the engine control module (ECM) indicating vehicle speed. Each engine revolution is represents 2 input pulses to the ECM. The instantaneous engine speed is calculated by the ECM using
the time difference between the 2 input pulses. The tachometer will default to 0 RPM if:
| • | The ignition is in OFF, ACCESSORY, or CRANK. |
| • | The time duration since the last pulse is greater than or equal to 1 second. |
