For 1990-2009 cars

### Fuel Gauge

The instrument panel uses an electronic fuel gauge. The fuel gauges consists of an instrument cluster gauge and a fuel tank sending unit. The fuel gauges indicates the quantity of fuel in the tank when the ignition switch is in RUN. The fuel gauge pointer may come to rest in any position when the ignition is set to any of the following positions:

• | OFF

• | LOCK

• | START

• | ACCESSORY

A fuel tank unit in the fuel tank changes resistance with the fuel level. The resistance varies from approximately 0 ohms at empty to 90 ohms at full. The instrument cluster reads the resistance value and assigns an appropriate value. The value can be between 0 (empty) and 255 (full) counts. The value is transmitted to the powertrain control module (PCM) via the serial data.

### Engine Coolant Temperature Gauge

The engine coolant temperature gauge indicates the temperature of the engine coolant when the ignition switch is in RUN. A coolant temperature sensor in the engine changes resistance with the coolant temperature. As the coolant temperature increases, the resistance of the sensor decreases. The PCM reads the resistance value and assigns an appropriate value. The value can be between 0-255 counts. The value is transmitted to the instrument cluster via the serial data. The instrument cluster reads the value and assigns a deflection value. The deflection value causes the needle in the gauges to turn. The gauge reads between 37.8°C to 113°C (100°F to 253°F).

### Tachometer (Up-Lever Cluster Only)

The tachometer indicates in engine speed in revolutions per minute (RPM) when the ignition switch is in RUN. The PCM supplies information to the instrument panel via the serial data. The instrument panel converts the data into an analog display.

### Speedometer

The speedometer is a road speed indicator. All instrument clusters are equipped with both a trip odometer and a season odometer. A vehicle speed sensor (VSS) (permanent magnet generator) is located on the transaxle. The VSS inputs to the PCM whenever the transaxle differential carrier turns. the PCM buffers the VSS signal and transmits the signal to the following components at 4000 pulses per mile via a hardwired connection (CKT 817):

• | The instrument cluster

• | The electronic brake control module (EBCM)

• | The diagnostic sensing module (SDM)

### Odometer

The odometer is driven by a stepper motor in the cluster. The odometer discs are geared so that as any one disc finishes a complete revolution, the next disc to the left is turned 1/10 of a revolution. The trip odometer may be reset to 0 when the driver pushes the trip odometer reset pin. The odometer receives data in the same manner as the speedometer.

### ABS Indicator

The yellow ABS indicator illuminates when the antilock brake system is partially or totally inhibited. The ABS indicator is controlled by the instrument cluster as commanded by the EBCM. If the ABS indicator is illuminated without the red brake indicator on, then normal power assisted braking is available but the anti-lock braking is inhibited. As a bulb check procedure, the EBCM commands this indicator on for 3 seconds when the ABS is powered up (the ignition is in RUN). When the ignition switch is in the OFF/UNLOCK or the CRANK positions (loss of EBCM serial data), the indicator illuminates.

### BRAKE Indicator

The BRAKE indicator lamp has 2 functions:

• | The lamp lights whenever the park brake is set.

• | A switch built into the brake master cylinder reservoir signals the EBCM if the brake fluid drops below a safe level.

The EBCM commands the indicator ON with the instrument cluster via the serial data. The cluster is commanded ON when the EBCM is initially powered up (the ignition switch in RUN). The indicator also lights when the ignition switch is in the OFF/LOCK or the CRANK positions (loss of EBCM serial data).

### ETS OFF (Option with 4 Speed Automatic Transaxle Only)

The enhanced traction system indicator is controlled by the instrument cluster as commanded by the EBCM via the serial data. This indicator lights under any of the following conditions:

• | The ETS is turned off

• | The ETS is unavailable due to a problem with the anti-lock brake system

The EBCM commands the indicator ON for 3 seconds when the ignition switch is in RUN as a bulb check procedure. During a loss of EBCM serial data communication (the ignition switch is in OFF/LOCK or CRANK), the indicator lights.

### LOW TRAC (Oldsmobile and Pontiac Option with 4 Speed Automatic Transaxle Only)

The LOW TRAC indicator is controlled by the instrument cluster as commanded by the EBCM via the serial data. The EBCM commands this indicator ON when the enhanced traction system is engaged. the EBCM commands this indicator ON for 3 when the ignition is in RUN as a bulb check procedure. During a loss of EBCM serial data communication (the ignition switch is in OFF/LOCK or CRANK), the indicator lights.

### Check Engine

The CHECK ENGINE indicator, or the malfunction indicator lamp, is in the instrument cluster. The CHECK ENGINE indicator illuminates when the ignition switch is in RUN and the engine is off. The light stays on for a short time after the engine starts and should turn off in 1-5 seconds. If the light stays on, or if the light comes on while driving, service to the emission system may be required. Refer to Engine Controls. This indicator is controlled via a hardwired connection with the PCM and the instrument cluster.

### Check Oil

The Check Oil indicator is controlled by the instrument cluster as commanded by the PCM via the serial data. The oil level is monitored by the PCM with an oil level switch. When the PCM determines a low oil condition, the PCM commands the Check Oil indicator ON. As a bulb check procedure, the PCM commands the indicator ON when the instrument cluster and the PCM are powered up (the ignition switch is in OFF/LOCK, RUN, or CRANK).

### CRUISE (Buick and Oldsmobile)

The CRUISE indicator is controlled by the instrument cluster as commanded by the PCM via the serial data. The cruise control is monitored by the PCM. When the cruise control is engaged, the PCM commands the indicator ON. As a bulb check procedure, the PCM commands the indicator ON when the instrument cluster and the PCM are powered up (the ignition switch is in the OFF/LOCK, RUN or CRANK positions.)

### Oil Pressure

The engine oil pressure indicator is controlled by the instrument cluster as commanded by the PCM via the serial data. The oil pressure indicator lights when the engine is running and the oil pressure drops below approximately 13.8 kpa (2 psi). As a bulb check procedure, the PCM commands the indicator ON when the instrument cluster and the PCM are powered up (the ignition switch is in OFF/LOCK, RUN or CRANK).

### Low Coolant

The low coolant switch is located in the coolant surge tank. the instrument cluster contains the low coolant indicator. The instrument cluster illuminates this indicator when commanded by the PCM. If the coolant in the surge tank is low, the low coolant indicator illuminates and remains ON until one of the following actions in met:

• | Until the ignition switch is turned OFF

• | The coolant in the surge tank is returned to a normal level

As a bulb check procedure, the instrument cluster illuminates this indicator for 3 seconds when the instrument cluster is initially powered up (the ignition switch is in OFF/LOCK, RUN or CRANK).

### Up Shift (Manual Transaxle Only)

The upshift indicator illuminates in order to indicate the optimum shift pints for maximum fuel economy. When this indicator is ON, shift the transaxle to the next higher gear range if the conditions permit. This indicator is controlled by the instrument cluster as commanded by the PCM via the serial data. This indicator does not illuminate as a result of serial data loss (the ignition switch is in OFF/LOCK).

### Volts

The volts indicator is controlled by both the PCM and instrument cluster. The instrument cluster illuminates the indicator when the ignition switch is in OFF/LOCK, RUN, or CRANK. The indicator turns OFF when the PCM sends the generator information via the serial data. Then the PCM may illuminate the indicator. The PCM may illuminate the indicator when the engine is running and the charging system voltage falls below 10 volts or more than 16 volts. This indicates that service is required. During a loss of serial data, when the ignition switch is in the OFF/LOCK position, the indicator illuminates continuously.

### PRNDL (Buick with Automatic Transaxle Only)

The PRNDL indicators are controlled by the instrument cluster as commanded by the PCM via the serial data. These indicators display the transaxle gear position. As a bulb check procedure, the PCM commands the indicator ON when the instrument cluster and the PCM are powered up (the ignition switch is in OFF/LOCK, RUN or CRANK) and the engine is not running. Vehicles with center consoles have an additional PRNDL display from the PRNDL control module. Refer to PRNDL Control Module.

### AIR BAG

The AIR BAG indicator is controlled by the sensing diagnostic module (SDM) via the serial data with the instrument cluster. The AIR BAG indicator alerts the driver of a potential SIR system problem which could prevent the proper deployment of the air bag. When the ignition switch lock cylinder is in RUN, the instrument cluster turns ON the AIR BAG indicator until the instrument cluster receives a valid turn off command from the SDM. The AIR BAG indicator flashes 7 times in order to indicate that the SIR system has performed self diagnostics. If the indicator does not turn OFF after that self check, then a system malfunction may exist. Refer to SIR Diagnostic System Check in SIR. During a loss of serial data, when the ignition switch is in OFF/LOCK, the indicator illuminates continuously.

### Seat Belt

The seat belt indicator is controlled by the instrument cluster via the serial data based on the status of the seat belt switch. The seat belt switch status is received from the SDM. The indicator illuminates when the ignition is in RUN or CRANK and the driver's safety belt is not fastened. The multi-function alarm module sounds when the ignition switch is in RUN and the driver's safety belt is not fastened. The chime will silence as soon as the driver's safety belt is fastened, or within 6 seconds, whichever occurs first. The seat belt indicator illuminates continuously for 20 seconds and then flash for an additional 55 seconds. The indicator turns OFF as soon as the driver's safety belt is fastened or the light times out, whichever occurs first. Note that unbuckling the seat belt results in the sequence repeating. During a loss of serial data, when the ignition switch is in OFF/LOCK, The indicator illuminates continuously.

### CHECK GAUGES (Buick and Oldsmobile)

The CHECK GAUGES indicator is controlled by the instrument cluster. The instrument cluster illuminates this indicator under any of the following conditions:

• | The engine coolant temperature gauge reaches the warming level.

• | The fuel gauge reaches a low level.

As a bulb check procedure, the instrument cluster illuminates this indicator for 3 seconds when the instrument cluster is powered up (the ignition switch is in OFF/LOCK, RUN or CRANK).

### Fuel Gauge Check (Pontiac)

The fuel gauge check indicator is controlled by the instrument cluster. The fuel check gauge is located within the fuel gauge. The instrument cluster illuminates the indicator when the fuel gauge reaches a warning level. As a bulb check procedure, the instrument cluster illuminates this indicator for 3 seconds when the instrument cluster is powered up (the ignition switch is in OFF/LOCK, RUN or CRANK).

### High Beam

The high beam indicator illuminates during flash-to-pass or whenever the headlights are on and high beams are selected. This indicator is controlled by the instrument cluster.

### Left and Right Turn Signal Indicators

The left turn indicator flashes in order to indicate that the left turn signals are on under the following conditions:

• | The ignition switch is in RUN

• | The hazard flashers are OFF

• | The turn signal lever is pulled down in order to indicate a left turn

The right turn indicator flashes in order to indicate that the right turn signals are in when the turn signal is lifted up from the center position. You will hear a click as an audible reminder that the turn signal is ON.

Both the left and the right turn signals flash simultaneously in order to indicate the hazard flashers are on under the following circumstances:

• | The ignition switch is in any position

• | The turn signal lever is in any position

• | The hazard switch is pressed in

The turn signal indicators are turned ON by the instrument cluster when appropriate input signals exist. When the hazard flashers are on, the turn signals are disabled. Normal turn signal operation is restored when the hazard flashers are turned OFF.

### LOW WASH (Oldsmobile)

The LOW WASH indicator is controlled by the instrument cluster. The LOW WASH indicator illuminates when the windshield washer fluid level reaches a warming level. The instrument cluster receives this input from the washer solvent level sensor. As a bulb check procedure, the instrument cluster illuminates this indicator for 3 seconds when the instrument cluster is powered up (the ignition switch is in OFF/LOCK, RUN or CRANK).

### SECURITY (Oldsmobile)

The SECURITY indicator shows the security state of the vehicle. The SECURITY is controlled by the instrument cluster. Refer to Theft Deterrent System.

### THEFT SYSTEM (Buick and Pontiac)

The THEFT SYSTEM indicator shows the security state of the vehicle. The indicator is controlled by the instrument cluster. Refer to Theft Deterrent Systems.