Principles of Operation

PRINCIPLES OF OPERATION

When installing a new instrument cluster, it is necessary to upload the module configuration information to the diagnostic tool. Following installation of the instrument cluster, download the module configuration information from the diagnostic tool into the new instrument cluster. The following items are configurable:
- AWD
- compass
- anti-lock brake system/traction control/intervehicle dynamics (ABS/TC/IVD)
- overspeed warning chime
- low coolant warning indicator
- climate control type
- oil life threshold
- powertrain control module (PCM) oil life used
- default language

The instrument cluster contains an analog speedometer, tachometer, fuel gauge, and engine coolant temperature gauge. The instrument cluster receives the information over the controller area network (CAN) circuits. The instrument cluster carries out a display prove-out to verify that the warning/indicator lamps and monitored systems are operating correctly. When the ignition switch is turned to the ON position, the charging system, low oil pressure, and the malfunction indicator lamp (MIL) illuminate until the engine is started and operating normally.

Each time the ignition switch is turned from OFF to ON, the following instrument cluster warning indicators will prove out:
- air bag (6 seconds)
- ABS (3 seconds)
- BRAKE (3 seconds)
- low coolant level (3 seconds)
- low fuel (3 seconds)
- low washer fluid (3 seconds)
- safety belt (60 seconds or until the safety belt is buckled)
- traction control (3 seconds)
- anti-theft (3 seconds)
- electronic throttle control (ETC) (3 seconds)
- check fuel cap (3 seconds)

Instrument Cluster Gauges

Engine Coolant Temperature Gauge
The powertrain control module (PCM) receives the engine coolant temperature status through hardwired circuitry to the engine coolant temperature (ECT) sensor. The instrument cluster receives the engine coolant temperature data from the PCM over the communication network. The instrument cluster monitors the engine coolant temperature data received from the PCM and commands the engine coolant temperature gauge pointer.

Fuel Gauge
The fuel level gauge informs the driver of the amount of fuel remaining in the tank. The fuel tank is a saddle tank design with variable resistance senders, driven by floats, that provide resistances related to fuel height, in each side, to the cluster via hardwired inputs. The fuel level is read from each fuel sender via a 2 wire input. The fuel sender shall provide variable resistance between 15 ohms (empty tank) and 160 ohms (full tank) ± 1% for a forward sender. If the fuel level is low, the resistance in the fuel level sensor will be low, causing the gauge to indicate empty (E). When the fuel level is high, the resistance in the fuel level sensor is high, and the gauge indicates full (F).

Speedometer
The instrument cluster receives the vehicle speed sensor (VSS) signal from the anti-lock brake system (ABS) module over the communication network, and monitors the VSS input and commands the speedometer pointer.

Tachometer
The instrument cluster receives the tachometer data from the PCM over the communication network and commands the tachometer pointer between 0 and 7,000 rpm, according to the data.

Indicators

Air Bag
The air bag warning indicator is used to provide a status of the supplemental restraint system. The instrument cluster receives a message from the restraint control module (RCM) over the communication network. If an air bag system concern is detected, a DTC is logged and the RCM sends a message to the instrument cluster to turn on the air bag warning indicator.

Anti-Lock Brake System (ABS)
The ABS warning indicator informs the driver of a malfunction in the ABS system. Inputs are provided by the ABS module over the communication network.

Brake System
The brake warning indicator alerts the driver if any of the following brake system conditions are present: the parking brake is set, the brake fluid level is low, the ABS module has detected a base brake system failure, there has been a loss of communication between the instrument cluster and the smart junction box (SJB), and there has been a loss of communication between the instrument cluster and the ABS module.

Charging System
The powertrain control module (PCM) constantly monitors the generator regulator output. When the PCM detects a continuous high or low output signal, or when the ignition switch is ON and the engine is OFF, the PCM sends a message over the communication network to the instrument cluster to illuminate the charging system warning indicator. When the ignition switch is in the ON position, with the engine running, and the PCM determines that the set point for the regulator has been met, the PCM sends a message to the instrument cluster to turn off the charging system warning indicator.

Low Fuel
The low fuel warning indicator is controlled by the instrument cluster and warns the driver when the fuel level is 1/8 of a tank or lower.

Low Oil Pressure
The oil pressure switch is hardwired to the smart junction box (SJB). When there is low or no oil pressure, the SJB sends a message over the communication network to the instrument cluster to illuminate the low oil pressure warning indicator according to engine oil pressure.

Safety Belt
The safety belt warning indicator informs the driver that their safety belt and/or the front passenger's safety belt is unbuckled. The first 65 seconds after the ignition switch transitions from Off or ACC to Run or Start, the safety belt warning indicator and the associated chime are used as a reminder to the driver that the front row safety belts have not been buckled. In this first 65 seconds the indicator illuminates when the driver and/or front passenger safety belt is unbuckled (with a person in the seat) and turns off whenever the safety belt(s) in the occupied front row seat(s) are buckled. The indicator re-illuminates if a safety belt is unbuckled after both have been buckled and the 65 seconds has not yet expired. After 65 seconds, the indicator turns off regardless of the front row safety belts status.

Check Fuel Cap
The PCM monitors pressure in the fuel evaporative system and detects massive or critical losses of pressure. When a critical loss of pressure in the fuel evaporative system is detected, the PCM provides a message over the communication network and the instrument cluster illuminates the check fuel cap warning indicator.

Traction Control
The traction control indicator flashes when the vehicle traction control is in active mode or is being controlled by the anti-lock brake system (ABS) module. The instrument cluster receives the traction control signal from the ABS module through the communication network. The instrument cluster monitors the traction control signal, and when the ABS module detects a traction control concern, the instrument cluster illuminates the traction control indicator.

Malfunction Indicator Lamp (MIL)
The MIL is illuminated when a DTC is detected by the PCM. The instrument cluster receives the MIL data from the PCM through the communication network.

Anti-Theft
The anti-theft indicator provides an indication in the ignition switch OFF position that there is an anti-theft system in the vehicle. When the ignition switch is in the ON position, the anti-theft indicator indicates whether or not a problem has been detected with the anti-theft system, and indicates what the problem is by illuminating the indicator for 60 seconds (solid or flashing) and then flashing a fault code 10 times. The indicator is controlled by the PCM via hardwired circuits.

Door Ajar
The door ajar indicator informs the driver that one or more doors, the decklid, or the liftgate is open while the ignition switch is in RUN position. When a door, decklid, or the liftgate is ajar, the SJB sends a message to the instrument cluster to turn the door ajar indicator on.

Low Coolant Level
The low coolant warning indicator, located in the degas bottle, illuminates when a low coolant level has been detected. The SJB receives the information from the low coolant level switch and sends the instrument cluster a message over the communication network to turn on the low coolant warning indicator.

Low Washer Fluid
The low washer fluid indicator, located in the windshield washer fluid reservoir, illuminates when a low washer fluid level has been detected. The SJB receives the information from the low washer fluid level switch and sends the instrument cluster a message over the communication network to turn on the low washer fluid indicator.

Electronic Throttle Control (ETC)
The PCM and the transmission control module (TCM) monitor the ETC system and provide the instrument cluster with the ETC status over the communication network. When a system concern is detected, the PCM or the TCM provide the instrument cluster with a signal commanding the instrument cluster to turn the ETC indicator on.

Speed Control
The instrument cluster receives the speed control data from the PCM through the communication network. When the speed control is engaged, the PCM provides a signal to the instrument cluster to turn the speed control indicator on.

High Beam
When the high beams are turned on, the SJB sends a signal to the instrument cluster through the communication network to illuminate the high beam indicator.

Turn Signal
The SJB sends a message to the instrument cluster over the communication network when the multifunction switch is in the RH and LH turn position. When the multifunction switch is in the RH or LH turn position, the instrument cluster flashes the RH or LH turn indicators.