Principles of Operation (How Does It Work)
Speedometer GaugeThe Hybrid Electronic Instrument Cluster (HEC) receives the vehicle speed signal from the Powertrain Control Module (PCM) over the Standard Corporate Protocol (SCP) network and displays it on the speedometer gauge. If the instrument cluster receives no vehicle speed signal after one second, the speedometer defaults to 0.0 km/h (0.0 mph).
Fuel Gauge
The instrument cluster receives the fuel level information directly from the fuel sender. When the instrument cluster fails to receive the fuel level signal for more than 33 seconds, then the fuel level gauge will move below E (empty). If the fuel level signal then operates correctly for more than 33 seconds, the fuel gauge will return to the correct position.
Fuel fills of less than 22.7 liters (6 gallons) require at least 5 to 20 minutes to update the fuel gauge indication.
Engine Coolant Temperature Gauge
Engine coolant temperature information is received by the instrument cluster from the PCM over the SCP network. Temperatures over 121°C (275°F) will display hot (H). If the engine coolant temperature data is missing or invalid for five seconds, the instrument cluster will move the engine coolant temperature gauge below the cold (C) position.
Odometer
The instrument cluster receives odometer rolling count status from the PCM and stores the mileage in Non-Volatile Memory (NVM). When the instrument cluster fails to receive the odometer rolling count status for more than two seconds, the odometer display will show dashes.
Air Suspension Indicator
The CK SUSP indicator will be illuminated if the instrument cluster receives a ground signal from the air suspension control module. The air suspension indicator will prove out when the ignition switch is placed in the START position and then in the RUN position.
Low Oil Pressure Indicator and Gauge
The low oil pressure indicator on the instrument cluster receives the oil pressure status directly from the oil pressure switch. The two-position oil pressure gauge will display either normal or no oil pressure. The low oil pressure indicator will prove out when the ignition switch is placed in the START position and then in the RUN position.
Brake Warning Indicator
The BRAKE indicator will prove out when the ignition switch is placed in the START and then in the RUN position. The BRAKE indicator will also be illuminated when the instrument cluster receives a ground signal from the parking brake switch or the brake fluid level switch.
Safety Belt Indicator
The seat belt switch is hardwired to the Generic Electronic Module (GEM). The safety belt warning indicator will be illuminated when the GEM sends a ground signal to the instrument cluster. The safety belt indicator will prove out when the ignition switch is placed in the START position and then in the RUN position.
Yellow ABS Warning Indicator
The ABS indicator will be illuminated when the anti-lock brake control module sends an open signal to the instrument cluster. The prove out of the ABS indicator is controlled by the anti-lock brake control module.
Service Engine Soon Indicator
After the engine is started, the SERVICE ENGINE SOON indicator will prove out for a duration of three seconds. If the instrument cluster does not receive a message from the PCM within five seconds, the instrument cluster will send two messages to the PCM and attempt to reestablish communication. If the instrument cluster is unable to establish communication, the instrument cluster will illuminate the SERVICE ENGINE SOON indicator and log a Diagnostic Trouble Code (DTC).
High Beam Indicator
The high beam indicator will illuminate when the multifunction switch is in the high beam position and sends a battery signal to the instrument cluster.
Right and Left Turn Indicator
The right and left turn indicators will illuminate when the multifunction switch is in either turn signal position or hazard lamps position and sends a battery signal to the instrument cluster.
Air Bag Indicator
The air bag indicator will be illuminated when the Restraint Control Module (RCM) sends a ground signal to the instrument cluster. The prove out of the air bag indicator is controlled by the RCM.
Anti-Theft Indicator
The THEFT indicator provides Passive Anti-Theft System (PATS) prove out. The THEFT indicator will prove out for three seconds following the ignition switch cycle and will flash following the ignition OFF to indicate that PATS is active.
Charging System Indicator
The charging system indicator will be illuminated when the generator sends a ground signal to the instrument cluster.
4X4 High Indicator
The 4X4 high indicator will be illuminated when the vehicle is in 4X4 high mode and the GEM sends a ground signal to the instrument cluster. The 4X4 high indicator will prove out when the ignition switch is placed in the START position and then in the RUN position.
Low Range Indicator
The LOW RANGE indicator will be illuminated when the vehicle is in 4X4 low and the PCM sends a message to the instrument cluster via the SCP network. The low range indicator will prove out when the ignition switch is placed in the START position and then in the RUN position.
Low Washer Indicator
The low washer indicator will prove out when the ignition switch is placed in the START position and then in the RUN position. The low washer indicator will be illuminated when the GEM provides a ground signal to the instrument cluster.
Door Ajar Indicator
The door ajar indicator will prove out when the ignition switch is placed in the START position and then in the RUN position. The door ajar indicator will be illuminated when the GEM provides a ground signal to the instrument cluster.
Low Fuel Indicator
The low fuel indicator will prove out when the ignition switch is placed in the START position and then in the RUN position. The low fuel indicator will illuminate when the fuel level gets low. The instrument cluster receives the fuel level information directly from the fuel sender.
Cruise Indicator
The CRUISE indicator will illuminate when the cruise control ON switch is depressed, the vehicle speed is above 48 km/h (30 mph) and the SET/ACCEL switch is depressed.