Instrument Cluster

INSTRUMENT CLUSTER

The base and optional instrument clusters both contain gauges, indicator lamps, and warning lamps that are designed to provide the driver with system status and to alert the driver that certain conditions exist in the vehicle. The optional instrument cluster contains the message center and is located in the center of the cluster between the tachometer and the speedometer. Gauges provide information to the driver indicating the status of systems. The systems that use gauges include vehicle speed, fuel level, engine coolant temperature, and engine rpm. Indicator lamps provide information to the driver of conditions that exist in the vehicle. The indicator lamps include the turn signal, low washer fluid level, traction control, and speed control. Warning indicator lamps provide information to the driver of conditions that could potentially alter vehicle performance. Examples of the warning indicators include the ABS, BRAKE, safety belt, air bag, and low oil pressure.

PRINCIPLES OF OPERATION

NOTE: The instrument cluster and the smart junction box (SJB) must be reconfigured upon replacement.

The instrument cluster is a hybrid electronic instrument cluster (HEC). The instrument cluster and the smart junction box use a combination of hardwired circuitry and the standard corporate protocol (SCP) communication network to transmit and receive information. It is very important to understand:
- where the input originates from.
- all the information necessary in order for a feature to operate.
- which module(s) receive(s) the input or command message.
- whether the module which received the input controls the output of the feature, or whether it outputs a message over the SCP communication network to another module.
- which module controls the output of the feature.

Warning Indicators
Each time the key is turned from OFF to ON, the charging system indicator, the low oil pressure indicator and the malfunction indicator lamp (MIL) will prove out and remain on until the engine is started. The safety belt indicator will prove out for 60 seconds. The air bag indicator will prove out for approximately 6-8 seconds while the following instrument cluster indicators and warning indicators will prove out for approximately 3 seconds:
- anti-lock brake system (ABS)
- check tire
- failsafe cooling (base cluster only)
- lamp out (base cluster only)
- charging system
- door ajar (base cluster only)
- low fuel
- BRAKE system
- TRAC OFF (if equipped)
- TRAC ACTIVE (if equipped)(base cluster only)
- check fuel cap
- transmission malfunction
- low washer fluid level (base cluster only)

The Low Tire Warning Indicator
The low tire pressure monitoring system detects a significant loss of inflation in a single wheel by utilizing the anti-lock brake system (ABS) to monitor the wheel speed sensors for small changes in wheel speed, indicating a low tire. Upon initialization, the low tire pressure monitoring system records the relative wheel speeds of the vehicle for future reference. During operation, the system compares the current vehicle wheel speeds to the recorded wheel speeds. If a tire loses air pressure with respect to the other tires, the ABS module will send a signal via the standard corporate protocol (SCP) network to the instrument cluster and illuminate the low tire warning indicator.

Following the correction of a low tire, the system must be re-initialized. Place the ignition switch in the ON position, press the odometer/trip odometer button 2 times until the display reads "TIRE RESET" or "CHECK TIRES AND RESET". Press and hold the odometer/trip odometer button for approximately 3 seconds until the low tire warning indicator flashes 3 times, indicating the system is initializing.

The Check Fuel Cap Indicator
The check fuel cap indicator is used to indicate significant leaks in the fuel tank evaporative system due to a loose fuel cap. Fuel tank pressure is monitored by the PCM. If a leak is detected, it signals a fault to the instrument cluster via the SCP network. Once the PCM has detected a loose fuel cap and the check fuel cap indicator is illuminated, the check fuel cap indicator will remain illuminated until the fuel cap is secured and the vehicle has been running for several minutes.

The TRAC ACTIVE Indicator (if equipped)
The TRAC ACTIVE indicator illuminates during a traction control event if the vehicle is equipped with anti-lock brake system/traction control (ABS/TC) and the instrument cluster is configured for traction control.

The TRAC OFF Indicator (if equipped)
The TRAC OFF indicator illuminates if the traction/control switch is in the OFF position and the traction control had been disabled.

Gauges

Fuel Gauge
The fuel level sensor, part of the fuel pump module, is hardwired to the smart junction box (SJB). The SJB provides the fuel level status to the instrument cluster over the SCP communication network. When the fuel level is empty (E), the fuel pump module resistance is approximately 16 ohms ± 2 ohms and when the fuel level is full (F), the fuel pump module resistance is approximately 160 ohms ± 4 ohms.

Speedometer Gauge
The instrument cluster receives the vehicle speed signal from the anti-lock brake system (ABS) module over the SCP communication network and commands the speedometer with an appropriate pointer placement based upon the data received.

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

Temperature Gauge
The 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 via the SCP communication network. The instrument cluster monitors the engine coolant temperature data received from the PCM and commands the engine coolant temperature gauge indication with a corresponding movement of the pointer.

Warning Indicator Lamps

Air Bag Warning Indication
The supplemental restraint system is monitored and controlled by the restraint control module (RCM). The status of the supplemental system is sent from the RCM to the instrument cluster through hardwired circuitry. The air bag warning indicator is illuminated if the RCM sends a ground signal to the instrument cluster.

ABS Warning Indication
The ABS is monitored by the ABS, or the ABS/TC/stability assist module, which sends the status signal to the instrument cluster over the SCP communication network. The instrument cluster uses this input to determine whether or not there is a fault with the ABS, or the ABS/TC/stability assist system and turns on the ABS warning indicator according to the input.

Brake Warning Indication
The brake warning indicator supports 3 separate functions: base brake system failure, low brake fluid level, and engagement of the parking brake. These functions are controlled by the parking brake control switch, the brake fluid level switch and the brake system itself. The brake fluid level switch and the parking brake control switch are hardwired directly to the SJB. The status of both the brake fluid level and parking brake switches are sent from the SJB to the instrument cluster over circuits 1309 (RD/YE) and 1305 (DB). The base brake system status is monitored by the ABS/TC module and sent to the instrument cluster over the SCP communication network.

Charging System Warning Indicator
The charging system controls are accomplished through the PCM, which monitors the output of the generator through hardwired circuitry. The status of the charging system is then relayed from the PCM to the instrument cluster over the SCP communication network.

Door Ajar Warning Indication (Base Cluster Only)

Malfunction Indicator Lamp (MIL)
The malfunction indicator lamp (MIL) is illuminated when a diagnostic trouble code (DTC) is detected by the PCM. The instrument cluster receives the MIL data from the PCM via the SCP network.

Low Fuel Level Indication
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.

Safety Belt Warning Indicator
The instrument cluster receives the safety belt warning status from the RCM over circuits 1083 (LB/BK) and 608 (BK/YE). The safety belt switch is hardwired to the RCM. When the safety belt is fastened, the safety belt switch opens and removes the ground to the RCM and when the safety belt is unfastened, the safety belt switch closes and grounds the circuit to the RCM.

Indicator Lamps

TRAC ACTIVE
The status of the advance traction control system is communicated to the instrument cluster from the ABS/TC/stability assist module. When the advance traction control system is switched OFF, the instrument cluster illuminates the advance traction indicator and sends a message to the ABS module.

CHECK FUEL CAP
The check fuel cap indicator is used to indicate significant leaks in the fuel tank evaporative system due to a loose fuel cap. Fuel tank pressure is monitored by the PCM and if a leak is detected it signals a fault to the instrument cluster over the SCP network. Once the PCM has detected a loose fuel cap and the indicator is illuminated, the indicator will remain illuminated until the fuel cap is secured and the ignition switch has been cycled one time.

Speed Control Indicator
The speed control indicator is used to inform the driver that the speed control has been set or activated. When the speed control has been set, the speed control module will send a command to the instrument cluster over the SCP communication network to turn on the indicator.

High Beam Indication
The instrument cluster provides a ground for the high beam indicator. When the high beams are turned on, the multifunction switch provides a power signal to the instrument cluster through hardwired circuitry and illuminates the high beam indicator.

Lamp Out Indication (Base Cluster Only)
The lamp out information is delivered from the smart junction box (SJB) to the instrument cluster over the SCP network. The purpose of this indicator is to inform the driver that 1 or more of the exterior lamps are inoperative.

Low Washer Fluid Warning Indication (Base Cluster Only)
The instrument cluster is hardwired to the low washer fluid switch. The low washer fluid switch closes and provides a ground to the instrument cluster when the washer fluid is low, turning on the low washer fluid indicator. When the washer fluid is above the low level, the low washer fluid switch opens and removes the ground to the instrument cluster and the low washer fluid indicator turns off.

Low Oil Pressure Indication
The instrument cluster is hardwired to the oil pressure switch. The oil pressure switch unit consists of a diaphragm and contact points, which are normally open. When there is low (under 41 kPa [6 psi]) or no oil pressure, the oil pressure switch remains open, removing the ground to the instrument cluster. When sufficient oil pressure exists, the oil pressure switch closes, providing a ground signal to the instrument cluster. The instrument cluster monitors the oil pressure ground signal and commands the low oil pressure warning indicator on or off according to engine oil pressure.

Malfunction Indicator Lamp (MIL)
After the engine is started, the MIL proves out for a duration of 3 seconds. If the instrument cluster does not receive a message from the PCM within 5 seconds, it sends 2 messages to the PCM and attempt to reestablish communication. If the instrument cluster is unable to reestablish communication, the instrument cluster illuminates the MIL and logs a diagnostic trouble code (DTC).

Speed Control Indication
The speed control status is monitored by the PCM and then relayed to the instrument cluster via the SCP communication network. The speed control indicator illuminates when the speed control is set.

Traction Control Indication
The status of the traction control is communicated to the instrument cluster from the ABS/TC/stability assist module via the SCP communication network. When the traction control system is active, the ABS/TC/stability assist module sends a command to the instrument cluster to illuminate the traction control indicator.

Transmission Malfunction Indicator Lamp
When the transmission is malfunctioning the PCM sends the instrument cluster a message over the SCP communication network. The instrument cluster then turns on this indicator.

Turn Signal Indication
The instrument cluster provides a ground for the RH and LH turn indicators. When the multifunction switch is in the RH or LH turn position, power is supplied to the instrument cluster through hardwired circuitry and the RH or LH turn indicators flash on and off.