Fuel Gauge - Dodge Dakota Sport 2001 Service Manual

AN
ENGINE TEMPERATURE GAUGE (Continued)
instrument cluster 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 engine coolant temper-
ature gauge is an air core magnetic unit that receives
battery current on the instrument cluster electronic
circuit board through the fused ignition switch out-
put (run-start) circuit whenever the ignition switch is
in the On or Start positions. The cluster is pro-
grammed 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:
• Engine Temperature Message - Each time
the cluster receives a message from the PCM indicat-
ing the engine coolant temperature is between the
low end of normal [about 54° C (130° F) for gasoline
engines, or 65° C (149° F) for diesel engines] and the
high end of normal [about 129° C (264° F) for gaso-
line engines, or 120° C (248° F) for diesel engines],
the gauge needle is moved to the actual temperature
position on the gauge scale.
• Engine Temperature Low Message - Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature is below
the low end of normal [about 54° C (130° F) for gas-
oline engines, or 65° C (149° F) for diesel engines],
the gauge needle is held at the "C" increment at the
far left end of the gauge scale. The gauge needle
remains at the far left end of the scale until the clus-
ter receives a message from the PCM indicating that
the engine temperature is above about 54° C (130° F)
for gasoline engines, or 65° C (149° F) for diesel
engines, or until the ignition switch is turned to the
Off position, whichever occurs first.
• Engine Temperature High Message - Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature is above
about 122° C (251° F) for gasoline engines, or 108° C
(226° F) for diesel engines, the gauge needle is moved
to the appropriate position on the gauge scale, the
check gauges indicator is illuminated, and a single
chime tone is sounded. The check gauges indicator
remains illuminated until the cluster receives a mes-
sage from the PCM indicating that the engine tem-
perature is below about 119° C (246° F) for gasoline
engines, or 104° C (219° F) for diesel engines, or
until the ignition switch is turned to the Off position,
whichever occurs first. The chime tone feature will
only repeat during the same ignition cycle if the
check gauges indicator is cycled off and then on
again by the appropriate engine temperature mes-
sages from the PCM.
INSTRUMENT CLUSTER
• Message Failure - If the cluster fails to receive
an engine temperature message, it will hold the
gauge needle at the last indication until a new mes-
sage is received, or until the ignition switch is turned
to the Off position, whichever occurs first.
• 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 func-
tionality of the gauge and the cluster control cir-
cuitry.
The PCM continually monitors the engine coolant
temperature sensor to determine the engine operat-
ing temperature. The PCM then sends the proper
engine coolant temperature messages to the instru-
ment cluster. For further diagnosis of the engine cool-
ant temperature gauge or the instrument cluster
circuitry that controls the gauge, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). If the instrument cluster turns on
the check gauges indicator due to a high engine tem-
perature gauge reading, it may indicate that the
engine or the engine cooling system requires service.
For proper diagnosis of the engine coolant tempera-
ture sensor, the PCM, the PCI data bus, or the mes-
sage inputs to the instrument cluster that control the
engine coolant temperature gauge, a DRBIII
tool is required. Refer to the appropriate diagnostic
information.

FUEL GAUGE

DESCRIPTION
A fuel gauge is standard equipment on all instru-
ment clusters. The fuel gauge is located in the lower
right quadrant of the instrument cluster, below the
oil pressure gauge. The fuel gauge consists of a mov-
able gauge needle or pointer controlled by the instru-
ment cluster circuitry and a fixed 90 degree scale on
the cluster overlay that reads left-to-right from E (or
Empty) to F (or Full). An International Control and
Display Symbol icon for "Fuel" is located on the clus-
ter overlay, in the center of the gauge directly above
the hub of the gauge needle. An arrowhead pointed
to the left side of the vehicle is imprinted on the clus-
ter overlay next to the "Fuel" icon in the fuel gauge
to provide the driver with a reminder as to the loca-
tion of the fuel filler access. The fuel gauge graphics
are white against a black field except for a single red
graduation at the low end of the gauge scale, 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 graph-
ics appear blue-green and the red graphics appear
8J - 19
scan