Meters
ODOMETER
An odometer and trip odometer are standard equipment in all instrument clusters. The odometer and trip odometer information are displayed in a common electronic Vacuum Fluorescent Display (VFD), which is centered on the lower edge of the instrument cluster and visible through a small window cutout on the instrument cluster overlay However, the odometer and trip odometer information are not displayed simultaneously The trip odometer reset switch on the instrument cluster electronic circuit board toggles the display between odometer and trip odometer modes by depressing the odometer/trip odometer switch knob that extends through the lower edge of the cluster lens, just right of the odometer VFD. Both the odometer and trip odometer information is stored in the instrument cluster memory.
The odometer can display values up to 999,999 kilometers (999,999 miles). The odometer will not roll over, but will latch at the maximum value. The trip odometer can display values up to 9999.9 kilometers (9999.9 miles) before it rolls over to zero. The odometer display does not have a decimal point and will not show values less than a full unit (kilometer or mile), the trip odometer display does have a decimal point and will show tenths of a unit (kilometer or mile). The unit of measure for the odometer and trip odometer display is not shown in the VFD. If the instrument cluster has a speedometer with a primary scale in kilometers-per-hour, the letters "KM" are printed on the cluster mask next to the VFD window to indicate the odometer unit of measure. During daylight hours (exterior lamps OFF) the VFD is illuminated at full brightness for clear visibility At night (exterior lamps are ON) an analog/digital (A/D) converter on the instrument cluster electronic circuit board converts the analog panel lamps dimmer input from the left multi-function switch to a digital dimming level signal for controlling the lighting level of the VFD. However, a "Parade" mode position of the panel lamps dimmer control ring of the left multi- function switch control stalk allows the VFD to be illuminated at full brightness while the exterior lamps are turned ON during daylight hours.
The VFD, the trip odometer switch, and the trip odometer switch button are serviced as a unit with the instrument cluster. The rubber trip odometer reset knob boot on the outside of the cluster lens is available for separate service replacement.
The odometer and trip odometer give an indication to the vehicle operator of the distance the vehicle has traveled. This gauge is controlled by the instrument cluster electronic circuitry based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The odometer and trip odometer information is displayed by the instrument cluster Vacuum Fluorescent Display (VFD), and the VFD will display odometer or trip odometer cluster information whenever the driver door is opened or the ignition switch is turned to the ON or Start positions.
The instrument cluster circuitry controls the VFD and provides the following features:
* Odometer/Trip Odometer Display Toggling - Actuating the trip odometer reset switch momentarily with the VFD illuminated will toggle the display between the odometer and trip odometer information. Each time the VFD is illuminated the display will automatically return to the last mode previously selected (odometer or trip odometer).
* Trip Odometer Reset - When the trip odometer reset switch is pressed and held for longer than about two seconds, trip odometer will be reset to 0.0 kilometers (miles). The VFD must be displaying the trip odometer information in order for the trip odometer information to be reset.
* Message Failure - If the cluster fails to receive a distance message during normal operation, it will hold and display the last data received until the ignition switch is turned to the OFF position. If the cluster does not receive a distance message within one second after the ignition switch is turned to the ON position, it will display the last distance message stored in the cluster memory. If the cluster is unable to display distance information due to an error internal to the cluster, either "888888"will be displayed in the VFD or the VFD will be blank.
* Actuator Test - Each time the cluster is put through the actuator test, the VFD will scroll the number "8" from right-to-left across the display then illuminate the trip odometer decimal point . in order to confirm the functionality of the VFD and the cluster control circuitry.
The PCM continually monitors the vehicle speed sensor, then sends the proper distance messages to the instrument cluster. For proper diagnosis of the vehicle speed sensor, the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the odometer/trip odometer, a DRBIII scan tool is required Refer to the appropriate diagnostic information.
SPEEDOMETER
A speedometer is standard equipment in all instrument clusters. The speedometer is located next to the tachometer, just to the right of center in the instrument cluster. The speedometer consists of a movable gauge needle or pointer controlled by the instrument cluster electronic circuitry and a fixed 210 degree primary outer scale on the cluster overlay that reads left-to-right either from 0 to 100 mph, from 0 to 110 mph, or from 0 to 180 km/h, depending upon the requirements of the market for which the vehicle was manufactured. Each version also has a secondary inner scale on the cluster overlay that provides the equivalent opposite units from the primary scale. A label on the cluster overlay beneath the hub of the speedometer pointer abbreviates the unit of measure for the primary scale in all upper case letters (i.e.: MPH or KM/H), followed by the unit of measure for the secondary scale in all lower case letters (i.e.: mph or km/h). The speedometer graphics are white (primary scale) and blue (secondary scale) against a black field, making them clearly visible within the instrument cluster in daylight. When illuminated from behind by the panel lamps dimmer controlled cluster illumination lighting with the exterior lamps turned ON, the white graphics appear white and the blue graphics appear blue. The orange gauge needle is internally illuminated. Gauge illumination is provided by replaceable incandescent bulb and bulb holder units located on the instrument cluster electronic circuit board. The speedometer is serviced as a unit with the instrument cluster.
The speedometer gives an indication to the vehicle operator of the vehicle road speed. This gauge is controlled by the instrument cluster electronic circuit board based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The speedometer is an air core magnetic unit that receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or Start positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the OFF position.
The instrument cluster circuitry controls the gauge needle position and provides the following features:
* Vehicle Speed Message - Each time the cluster receives a vehicle speed message from the PCM it will calculate the correct vehicle speed reading and position the gauge needle at that speed position on the gauge scale. The cluster will receive a new vehicle speed message and reposition the gauge pointer accordingly about every 86 milliseconds. The gauge needle will continue to be positioned at the actual vehicle speed position on the gauge scale until the ignition switch is turned to the OFF position.
* Message Failure - If the cluster fails to receive a speedometer message, it will hold the gauge needle at the last indication for about six seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. If a new speedometer message is not received after about six seconds, the gauge needle will return to the far left (low) end of the scale.
* Actuator Test - Each time the cluster is put through the actuator test, the gauge needle will be swept to several calibration points on the gauge scale in a prescribed sequence in order to confirm the functionality of the gauge and the cluster control circuitry.
The PCM continually monitors the vehicle speed sensor to determine the vehicle road speed, then sends the proper vehicle speed messages to the instrument cluster. For proper diagnosis of the vehicle speed sensor, the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the speedometer, a DRBIII scan tool is required. Refer to the appropriate diagnostic information.
TACHOMETER
A tachometer is standard equipment on all instrument clusters. The tachometer is located next to the speedometer, just to the left of center in the instrument cluster. The tachometer consists of a movable gauge needle or pointer controlled by the instrument cluster electronic circuitry and a fixed 210 degree scale on the cluster overlay that reads left-to-right from 0 to 6. The text "X 1000 RPM" imprinted on the cluster overlay directly below the hub of the tachometer needle identifies that each number on the tachometer scale is to be multiplied by 1000 rpm. A red line on the high end of the gauge scale designates the engine overspeed area of the gauge. The tachometer graphics are white against a black field, except for the single red line, making them clearly visible within the instrument cluster in daylight. When illuminated from behind by the panel lamps dimmer controlled cluster illumination lighting with the exterior lamps turned ON, the white graphics appear white and the red graphics appear red. The orange gauge needle is internally illuminated. Gauge illumination is provided by replaceable incandescent bulb and bulb holder units located on the instrument cluster electronic circuit board. The tachometer is serviced as a unit with the instrument cluster.
The tachometer gives an indication to the vehicle operator of the engine speed. This gauge is controlled by the instrument cluster electronic circuit board based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Programmable Communications Interface (PCI) data bus. The tachometer is an air core magnetic unit that receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run- start) circuit whenever the ignition switch is in the ON or Start positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the OFF position.
The instrument cluster electronic circuitry controls the gauge needle position and provides the following features:
* Engine Speed Message - Each time the cluster receives an engine speed message from the PCM it will calculate the correct engine speed reading and position the gauge needle at that speed position on the gauge scale. The cluster will receive a new engine speed message and reposition the gauge pointer accordingly about every 86 milliseconds. The gauge needle will continue to be positioned at the actual engine speed position on the gauge scale until the ignition switch is turned to the OFF position.
* Message Failure - If the cluster fails to receive an engine speed message, it will hold the gauge needle at the last indication for about six seconds, or until the ignition switch is turned to the OFF position, whichever occurs first. If a new engine speed message is not received after about six seconds, the gauge needle will return to the far left (low) end of the scale.
* Actuator Test - Each time the cluster is put through the actuator test, the gauge needle will be swept to several calibration points on the gauge scale in a prescribed sequence to confirm the functionality of the gauge and the cluster control circuitry.
The PCM continually monitors the crankshaft position sensor to determine the engine speed, then sends the proper engine speed messages to the instrument cluster.
For proper diagnosis of the crankshaft position sensor, the PCM, the PCI data bus, or the message inputs to the instrument cluster that control the tachometer, a DRBIII scan tool is required. Refer to the appropriate diagnostic information.