Instrument Cluster

INSTRUMENT CLUSTER

The instrument cluster contains 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. Gauges provide information to the driver indicating the status of systems. The gauges include vehicle speed, oil pressure, battery voltage gauge, 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, door ajar, electronic throttle control, high beam, 4x4 HIGH/LOW, AWD LOCK (if equipped), traction control, speed control and overdrive off. Warning indicator lamps provide information to the driver of conditions that could potentially alter vehicle performance. The warning indicators include the ABS, BRAKE, safety belt, air bag, CHECK GAUGE (if equipped), CHECK FUEL CAP (if equipped), low tire warning (if equipped), and low oil pressure.

PRINCIPLES OF OPERATION

The instrument cluster is a configurable, hybrid electronic cluster (HEC) that contains a microprocessor, gauges, indicator lamps, and internal circuitry. The instrument cluster is non-repairable with the exception of the instrument cluster lens. The instrument cluster utilizes hardwired circuitry, the controller area network (CAN), and universal asynchronous receiver transmitter (UART)-based protocol (UBP) communication networks. Communication using the CAN circuits transmits and receives data between the instrument cluster, the powertrain control module (PCM), the electronic automatic temperature control (EATC), the tire pressure monitoring system module, and the anti-lock brake system/traction control/integrated vehicle dynamics (ABS/TC/IVD) module. Communication using the UBP network utilizes data transmitted and received by the instrument cluster and the 4x4 control module, parking aid module, vehicle security module, and the driver seat module. The restraint control module (RCM) is hard wired to the instrument cluster on circuits 608 (BK/YE) and 1390 (DB).

Instrument Cluster Replacement

CAUTION: When installing a new instrument cluster, the instrument cluster must be re-configured.

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 CAN or UBP circuits to another module.
- which module controls the output of the feature.

The instrument cluster carries out a display prove-out to verify that the warning/indicator lamps and monitored systems are operating correctly. When the key is turned to the ON position with the engine off, the following indicators illuminate:
- 4x4 low indicator (3-second prove-out)
- 4x4 high indicator (3-second prove-out)
- check gauge warning indicator (3-second prove-out)
- ABS warning indicator (3-second prove-out)
- air bag warning indicator (6-second prove-out)
- BRAKE warning indicator (3-second prove-out)
- electronic throttle control indicator (3-second prove-out)
- tire pressure monitoring system indicator (3-second prove-out)
- traction control indicator (3-second prove-out)
- safety belt warning indicator (60-second prove-out)
- HI TEMP LOW OIL warning indicator (3-second prove-out)
- SERVICE ENGINE SOON warning indicator (3-second prove-out)
- charging system warning indicator (3-second prove-out)

Integrated Circuit Display
The integrated circuit display is a vacuum fluorescent tube display that contains the odometer, trip odometer, outside air temperature and compass display on base clusters and the message center display on message center clusters. The compass module and outside air temperature sensor are hardwired to the instrument cluster. The odometer information is transmitted from the PCM through the CAN circuits to the instrument cluster. The instrument cluster displays the appropriate message(s) upon receipt of the outside air temperature, compass heading and odometer data received.

Gauges

Speedometer
The instrument cluster receives the vehicle speed sensor (VSS) signal from the powertrain control module (PCM) through the CAN circuits. The instrument cluster monitors the VSS input from the PCM and commands the speedometer with a corresponding movement of the pointer.

Fuel Gauge
The fuel gauge receives its signal from the fuel level sensor, part of the fuel pump module. The fuel level sensor measures variable resistance in the fuel tank depending on the current fuel level. When the fuel level is low, resistance in the unit is low (15 ohms ± 1 ohm). When the fuel level is high, the resistance is high (160 ohms ± 2 ohms). If equipped with flex-fuel, the basic fuel level indication is the same except that the flex-fuel vehicles incorporate the use of a flex-fuel module. The flex-fuel module is a DC-AC-DC interface, used to prevent reactions created by the interaction of DC current with the fuel. The flex-fuel module is part of the fuel pump module and is installed as an assembly.

Engine Coolant 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 through the CAN circuits. The instrument cluster monitors the engine coolant temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer. If the instrument cluster receives no signal the temperature gauge defaults to the cold position.

Oil Pressure Gauge
The instrument cluster is hardwired to the engine oil pressure switch. The engine oil pressure switch consists of a diaphragm and contact points, which are normally open. When there is low or no oil pressure, the engine oil pressure switch remains open and removes the ground to the instrument cluster and when sufficient oil pressure exists, the engine oil pressure switch closes providing a ground signal to the instrument cluster. The instrument cluster monitors the oil pressure and commands the oil pressure gauge indication with a corresponding pointer movement.

Voltage Gauge
The voltage gauge displays the system battery voltage as measured at the instrument cluster run input.

Tachometer
The tachometer is electrically operated and indicates engine speed in revolutions per minute (rpm). The tachometer range is 0 to 7,000 rpm. The tachometer receives the signal through the CAN circuits from the PCM. If the rpm information sent to the instrument cluster is invalid or missing, the instrument cluster defaults the tachometer to 0 rpm.

Integrated Circuit Display

Odometer
The odometer and trip odometer are viewed through the message center in the integrated circuit display on message center clusters or in the integrated circuit display on base clusters. The odometer is tamper-resistant and accumulates and registers up to one million miles in English mode or one million kilometers in metric mode, based upon rolling count data sent from the PCM via the CAN circuits. The trip odometer is resettable and accumulates and registers up to 1,608 kilometers (999 miles).

Warning Indicator Lamps

Air Bag Warning Indicator
The instrument cluster is hardwired to the restraint control module (RCM). If an air bag system concern is detected, a Diagnostic Trouble Code (DTC) is logged and the RCM provides a ground path to the instrument cluster turning on the air bag indicator.

Anti-Lock Brake System (ABS) Warning Indicator
The ABS warning indicator is used to indicate an ABS concern or deactivation of the ABS. The instrument cluster, upon receipt of the ABS message from the ABS module through the CAN circuits, turns on the ABS warning indicator.

BRAKE Warning Indicator
The parking brake switch is hardwired to the instrument cluster and the brake fluid level switch is hardwired to the ABS module. The instrument cluster BRAKE warning indicator utilizes two inputs. The first input is provided by the parking brake switch and when applied, provides a ground to the instrument cluster turning on the BRAKE warning indicator. The second input is controlled by the ABS module. The ABS module, upon receipt of a low brake fluid level signal or base brake system concern, provides a brake signal to the instrument cluster through the CAN circuits. The instrument cluster, upon receipt of the brake signal, turns on or off the BRAKE warning indicator according to the monitored data.

Charging System Warning Indicator
The instrument cluster receives the charge signal from the PCM through the CAN circuits. When the generator output is insufficient to maintain the battery state of charge the instrument cluster illuminates the charging system indicator.

Check Gauge Warning Indicator
The check gauge warning indicator illuminates when any of the following conditions exist: the engine oil pressure drops below approximately 42 kPa (6 psi), the engine temperature exceeds approximately 118°C (244°F), the fuel level drops below approximately 15 percent of fuel system capacity. This indicator also flashes when the vehicle is in a fail-safe cooling event (base cluster only).

Door Ajar Warning Indicator (Base Cluster)
The door ajar switches provide a ground signal to the vehicle security module. The vehicle security module, upon receipt of the door ajar ground data, supplies a door ajar status message to the instrument cluster through the UBP communication network. The instrument cluster monitors the door ajar status and commands the door ajar indicator on or off according to the door ajar status message.

Safety Belt Warning Indicator
The restraint control module (RCM) monitors the safety belt position through the safety belt switch (part of the buckle). When the safety belt is buckled, the RCM receives a ground signal and sends a signal via circuit 1390 (DB) to the instrument cluster to turn off the safety belt warning indicator. When the safety belt is unbuckled, the ground to the RCM is removed and the RCM sends a signal via circuit 1390 (DB) to the instrument cluster to turn on the indicator.

Low Tire Warning Indicator
The tire pressure monitoring system has the ability to monitor the air pressure of all five tires. The tire-mounted pressure sensors transmit signals to the tire pressure monitoring system module by using the valve stem as an antenna. These transmissions are sent approximately every 60 seconds when the vehicle speed exceeds 32 km/h (20 mph). The tire pressure monitoring system module compares each tire pressure sensor transmission against low and high pressure limits. If the tire pressure monitoring system module determines that the tire pressure has exceeded the limit, the tire pressure monitoring system module communicates on the CAN circuits to the vehicle message center, which then displays a warning message. The system is not affected by wheel and tire rotation.

Indicator Lamps

CHECK FUEL CAP Indicator (Base Cluster)
The check fuel cap indicator is used to indicate significant leaks in the fuel tank evaporative system due to a loose fuel cap or other fuel evaporative system concerns. Fuel tank pressure is monitored by the PCM and once a leak is detected, the PCM signals a fault to the instrument cluster through the CAN circuits. Once the PCM has detected a loose fuel cap and the check fuel cap indicator is illuminated, the check fuel cap indicator remains illuminated until the fuel cap is secured and the vehicle has been running for several minutes or the ignition has been cycled once.

High Beam Indicator
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.

O/D OFF Indicator
The instrument cluster receives the overdrive off signal from the PCM through the CAN circuits. The overdrive off switch is hardwired to the PCM. When the transmission overdrive is selected off, the overdrive off switch provides a ground signal to the PCM. The PCM, upon receipt of the overdrive off ground signal, provides a CAN overdrive off signal to the instrument cluster and the instrument cluster will turn on the O/D OFF indicator.

RH and LH Turn Indicators
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.

SERVICE ENGINE SOON Indicator
The malfunction indicator lamp (MIL) is illuminated when a DTC is detected by the PCM. The instrument cluster receives the MIL data from the PCM through the CAN circuits.

Speed Control Indicator
The instrument cluster receives the speed control signal from the PCM through the CAN circuits. When the speed control is engaged, the PCM provides a ground to the instrument cluster and turns on the speed control indicator.

Traction Control Indicator (Message Center Cluster)
The traction control indicator flashes when the vehicle traction control is in active mode or is being controlled by the ABS/TC/IVD module. The instrument cluster receives the traction control signal from the anti-lock brake system/traction control/integrated vehicle dynamics (ABS/TC/IVD) module through the UBP communication network. The instrument cluster monitors the traction control signal and when the ABS/TC/IVD module detects a traction control concern, the instrument cluster turns on the traction control indicator.

HI TEMP LOW OIL (Message Center Cluster)
The hi temp low oil indicator illuminates when the engine coolant temperature is high or the engine oil pressure is low.

4x4 HIGH and 4x4 LOW Indicators
The instrument cluster receives the 4x4 HIGH and 4x4 LOW information from the four-wheel drive module through the UBP communication network. When either 4x4 high or 4x4 low are selected, the four-wheel drive control module provides a 4x4 status signal to the instrument cluster and turns on the appropriate indicator.

AWD LOCK (if equipped)
The instrument cluster receives the AWD indicator status from the 4x4 control module. When all-wheel drive is selected, the 4x4 control module provides an indicator on command over the UBP communication network to the instrument cluster to turn on the AWD LOCK indicator. The instrument cluster receives the electronic throttle control status from the PCM over the CAN circuits. When a system concern is detected, the PCM sends the instrument cluster a command signal to turn the electronic throttle control indicator ON.

Electronic Throttle Control
The instrument cluster receives the electronic throttle control status from the PCM over the CAN circuits. When a system concern is detected, the PCM sends the instrument cluster a command signal to turn the electronic throttle control indicator ON.