The instrument cluster scan tool data display values and
definition information can assist in diagnosing instrument cluster related
problems, especially when no diagnostic trouble codes (DTC) are
stored in memory. A vehicle scan tool data can be compared with
the data display values from a known good vehicle in the scan tool
data display table. When data from the vehicle differs from the
typical data display value, the data definition information will
help in understanding the nature of the difference and the source
of the problem.
Data
Battery Voltage -- Range: 9.0 - 19.0 Volts: This data refers to the battery system voltage as measured by the
instrument cluster (IPC).
Vehicle Speed -- Range: 0 MPH - 120 MPH (0 KM/H -
193 KM/H): This is the cluster measurement of the vehicle's speed from a discrete
input from the vehicle control module (VCM).
Monitored Coolant Temperature - Range: -40°F-419°F
(-40°C- 215°C): This data is the clusters measurement of the engine coolant temperature
as provided by the VCM on the class 2 serial data line. If a class 2 communication
failure occurs, this data will be -40°.
Monitored Fuel Level - Range: 0 - 100 percent: This data is the cluster's measurement of the fuel tank level as
provided by the VCM on the class 2 serial data line.
If a class 2 communication failure occurs, this data will be 0.
Displayed Odometer - Range: 0 Miles - 999,999 Miles/Kilometers: This data refers to the displayed odometer mileage on the odometer
display.
Displayed Trip Odometer - Range: 0 Miles - 9,999.9 Miles/Kilometers: This data refers to the displayed trip odometer mileage displayed
on the trip odometer display.
Inputs
PRNDL State - Range: Park / Reverse / Neutral / Drive / Third / Second
/ First / Invalid: This data input refers to the PRNDL position data that is communicated
to the cluster over the class 2 serial data line by the VCM. The value of
this parameter corresponds to the gear that is selected on the PRNDL
display. The value of this parameter will be INVALID under the following
conditions:
| • | The data from the VCM is INVALID. |
| • | The data from the VCM is PARK but the cluster does recognize the
class 2 message from the VCM. |
| • | A class 2 communication failure has occurred. |
When the value of this parameter is INVALID, no gear will be shown
as selected on the PRNDL display.
Dimming - Range: Active / Inactive: This data refers to the dimming availability feature of the PRNDL
and odometer/trip odometer vacuum florescent displays. ACTIVE is displayed
when the PRNDL and odometer/trip odometer vacuum florescent displays
can be dimmed using the dimming thumbwheel switch. INACTIVE is
displayed when the PRNDL and the odometer/trip odometer vacuum
florescent displays cannot be dimmed using the dimming thumbwheel
displays.
Park Switch - Range: Open / Closed: This data input refers to the state of the gear shift park position
switch. OPEN is displayed when the gear shift is not fully seated in park.
CLOSED is displayed when the gear shift is in the park position
and the gearshift lever is at the normal rest position.
Trip Reset Switch - Range: Active / Inactive: This data refers to the position of the trip odometer reset switch.
ACTIVE is displayed when the trip reset switch is pushed in. INACTIVE is
displayed when the trip reset switch is in the normal position
(not pushed in).
Outputs
Low Fuel Lamp - Range: ON / OFF: This output refers to the commanded state of the LOW FUEL indicator
located in the instrument cluster. ON is displayed when the instrument cluster
is commanding the LOW FUEL indicator ON. OFF is displayed when the instrument
cluster is not commanding the LOW FUEL indicator ON. The instrument cluster
will command the LOW FUEL indicator ON under the following conditions:
| • | When the instrument cluster receives a class 2 (percent monitored
fuel level) message of less than 18 percent from the VCM. Once the lamp is
ON, the Monitored Fuel Level must rise above 22 percent in order to turn
the lamp OFF. |
| • | A class 2 communication failure has occurred. |
This output refers to the commanded state of the All Wheel Drive
(AWD) lamp illumination by the instrument cluster. ON is displayed when the
instrument cluster is commanding the Service AWD lamp to be illuminated.
OFF is displayed when the instrument cluster is not commanding the Service
AWD lamp to be illuminated. The instrument cluster will illuminate the
Service AWD lamp when it receives a class 2 serial data message from the
Automatic Transfer Case (ATC) Module indicating an AWD malfunction.
Anti-Lock Brake System (ABS) Lamp - Range: ON / OFF: This output refers to the commanded state of the ABS lamp illumination
by the instrument cluster. ON is displayed when the instrument cluster is
commanding the ABS lamp to be illuminated. OFF is displayed when the instrument
cluster is not commanding the ABS lamp to be illuminated. The instrument
cluster will command the ABS lamp to be illuminated under the following
conditions:
| • | When the instrument cluster receives a class 2 message from the
electronic brake control module (EBCM) indicating there is a malfunction in
the ABS system |
| • | During the bulb check period for 3 seconds after the ignition
switch is first turned to RUN. |
| • | A class 2 communication failure occurs. |
This output refers to the commanded state of the BRAKE lamp illumination
by the instrument cluster. ON is displayed when the instrument cluster is
commanding the BRAKE lamp to be illuminated. OFF is displayed when the
instrument cluster is not commanding the BRAKE lamp to be illuminated.
The instrument cluster will command the BRAKE lamp to be illuminated
under the following conditions:
| • | The BRAKE lamp will flash when the instrument cluster receives
a class 2 message from the body control module (BCM) that the parking brake
is set. |
| • | When the instrument cluster receives a class 2 message from
the electronic brake control module (EBCM) that there is a problem with the
base brake system (non-ABS portion). |
| • | During the bulb check period for 3 seconds after the ignition
switch is first turned to the RUN position. |
This output refers to the commanded state of the fasten seat belts
lamp illumination by the instrument cluster. ON is displayed when the instrument
cluster is commanding the fasten seat belts lamp to be illuminated. OFF
is displayed when the instrument cluster is not commanding the
fasten seat belts lamp to be illuminated. The instrument cluster
will command the fasten seat belts lamp to be illuminated under
the following conditions:
| • | The fasten seat belt lamp will illuminate for 20 seconds followed
by 55 seconds of flashing when it receives a class 2 message from the body
control module (BCM) that the drivers seat belt is not buckled. |
| • | During the bulb check period for about 3 seconds after the ignition
switch is first turned to the RUN position providing the drivers seat belt
is not buckled. If the seat belt is buckled when the ignition switch
is turned to the RUN position, the seat belt indicator will remain
OFF. |
| • | If a class 2 communication failure occurs, the fasten seat belt
lamp will illuminate for 20 seconds followed by 55 seconds of flashing. |
This output refers to the commanded state of the SECURITY indicator
located on the instrument cluster. ON is displayed when the instrument cluster
is commanding the SECURITY indicator ON. OFF is displayed when the instrument
cluster is not commanding the SECURITY indicator ON. The instrument
cluster will command the SECURITY indicator to be displayed in the
under the following conditions:
| • | When the instrument cluster receives a class 2 serial data message
from the (BCM). |
| • | A class 2 communication failure occurs and the ignition switch
in the RUN position. |
This output refers to the commanded state of the high beam lamp
illumination by the instrument cluster . ON is displayed when the instrument
cluster is commanding the high beam lamp to be illuminated. OFF is displayed
when the instrument cluster is not commanding the high beam lamp to be
illuminated. The instrument cluster will illuminate the high
beam lamp when the instrument cluster receives a class 2 serial data message
from the body control module (BCM).
Battery - Range: ON / OFF: This output refers to the commanded state of the battery (voltage)
icon indicator on the instrument cluster. ON is displayed when the instrument
cluster is commanding the battery indicator ON. OFF is displayed when
the instrument cluster is not commanding the battery indicator ON. The
instrument cluster will command the battery indicator ON under the following
conditions:
| • | The instrument cluster receives a class 2 message from the VCM
indicating that there is a charging system problem. |
| • | The ignition switch is turned to UNLOCK or RUN without the engine
running. |
| • | A class 2 communication failure occurs. |
| • | During a 3 second bulb check after the engine has been started. |
This output refers to the commanded state of the TOW/HAUL indicator
located on the instrument cluster. ON is displayed when the instrument cluster
is commanding the TOW/HAUL indicator ON. OFF is displayed when the
instrument cluster is not commanding the TOW/HAUL ON. The indicator
will be ON when the TOW/HAUL switch is pressed and the body control
module (BCM) sends a class 2 serial data message to the instrument cluster.
Air Bag Lamp - Range: ON / OFF: This output refers to the commanded state of the Air Bag lamp illumination
by the Inflatable Restraint Sensing & Diagnostic Module (SDM). The Air
Bag lamp is controlled by a class 2 message from the SDM. ON is displayed
when the SDM commands the indicator ON. ON is displayed when the SDM
does not command the indicator ON.
Overspeed - Range: ON / OFF: This output refers to the commanded state of the Overspeed telltale
located in the instrument cluster. ON is displayed when the instrument cluster
is commanding the Overspeed telltale ON. OFF is displayed when the
instrument cluster is not commanding the Overspeed telltale ON. The instrument
cluster will display the Overspeed telltale when the instrument cluster
receives a class 2 serial data message from the BCM.
