on t he cluster overlay, directly below the high end of
the scale. J ust to the right of the icon , the nomencla -
ture “°C” or “°F” confirms th e unit of measu re for the
gauge re ad ings .
The engine coolant tempera ture ga uge graphics are
whit e aga inst a black field, except for a single red
gra duation a t th e far left (high ) end of th e gauge
sca le, makin g them clearly visible wit hin t he instr u-
ment cluster in daylight . When illuminat ed from
behind by the panel lamps dimmer controlled cluster
illumination lighting with th e ext erior lamps turned
On, t he whit e gr aphics appea r amber and th e red
gra phics a ppea r red. The oran ge ga uge needle is
internally illuminated. Gauge illu mination is pr o-
vided by Ligh t Emitting Diode (LE D) units soldered
onto t he instrument cluster electr onic cir cuit board.
The engine coolant temperatur e gauge is serviced a s
a unit with t he in st rumen t cluster.
OPERATION
The en gin e coolan t tem per atu re ga uge gives an
indication to th e veh icle oper ator of the engin e cool-
ant tem per ature. This gau ge is controlled by the
instr umen t clu st er circuit boa rd based u pon cluster
pr ogrammin g and electronic messa ges r eceived by
the cluster from th e Engine Contr ol Modu le (E CM)
over the Cont roller Area Network (CAN) data bus.
The engine coolan t temper atur e ga uge is an air core
magnetic unit tha t r eceives ba tter y current on the
instr umen t clu st er electron ic circu it board wh en th e
instr umen t clu st er detects th at t he ignition switch is
in t he On posit ion. The clu st er is program med t o
move t he ga uge needle back to th e low en d of the
sca le after the ign ition switch is tur ned to the Off
position . The instr umen t cluster circuitry controls
the gau ge n eedle position a nd provides the following
featu res:
• Engine Temperature Normal Message - Each
time t he cluster r eceives a message from the ECM
indicating the engine coolant tempera ture is with in
the normal opera ting range [up t o about 120° C (250°
F), the gau ge needle is moved to the actu al relative
temper ature position on the gau ge scale.
• Engine Temperature High Message - Each
time t he cluster r eceives a message from the ECM
indicating the engine coolant tem per atu re is high
[above about 120° C (250° F) the gau ge needle is
moved into the red warn ing zone on the ga uge sca le.
The ECM con tinually mon itors th e engine coola nt
temper ature sen sor to deter min e th e en gin e opera t-
ing tem per ature. The ECM t hen sends t he proper
engine coolant temper ature messa ges to the instru-
ment cluster. If th e in strument cluster moves the
engine coola nt tempera ture ga uge needle to red area
of the ga uge scale, it m ay indicate th at t he engine or
the engine cooling system r equir e service. For proper
diagnosis of the engine coolant temper ature sen sor,
the ECM, th e CAN dat a bus, th e electronic message
input s to th e in st rument cluster, or th e instrument
cluster circu itr y t hat controls th e engine coolant t em-
perat ure gauge, a diagnostic scan tool is requir ed.
Refer to t he appropriate diagnostic informat ion.
ESP I N DI CAT OR
DESCRIPTION
An Electron ic Stability Progra m (ESP) indicator is
st andar d equipm ent on a ll in st rumen t clust ers, but is
only function al on vehicles equipped with the
opt ional ESP system . The ESP indica tor is located
near the lower edge of th e instrument cluster, to the
right of the mu lti-function indicator display. The ESP
indicator consists of a stencil-like cu tout of the text
“ESP” in the opaqu e layer of the instrument clu st er
overlay. The da rk outer layer of the over lay prevent s
the indica tor fr om being clear ly visible when it is not
illuminated. An am ber Ligh t Emitt ing Diode (LE D)
behind th e cut out in the opa que layer of the overlay
causes th e text to appear in amber through the
translucen t ou ter layer of t he overlay wh en t he indi-
cator is illu min ated from behin d by th e LED, which
is soldered onto t he instr umen t clust er elect ronic cir-
cuit boa rd. The ESP indicator is ser viced a s a unit
with t he in st rumen t cluster.
OPERATION
The ESP indicator gives a n in dication to th e vehi-
cle oper ator when the E SP system is fau lty or inop-
erat ive. This indicator is controlled by a tr ansist or on
the instr umen t cluster circuit board based u pon clus-
ter progr amming and electr onic messages r eceived by
the clu st er from the Con troller Ant ilock Brake (CAB)
over the Cont roller Area Network (CAN) data bus.
The ESP indicator Ligh t Em itt ing Diode (LE D) is
complet ely controlled by th e instrument cluster logic
circuit, an d t hat logic will only allow this indica tor to
operat e wh en the instru ment cluster det ects t hat the
ign ition switch is in th e On position . Therefore, th e
LED will always be off wh en the ign ition switch is in
any position except On. The LED only illum inates
when it is provided a pa th to gr ound by the instru-
ment clu st er t ransist or. The in st rument clust er will
turn on th e ESP indica tor for the following rea son s:
• Bulb Test - Ea ch time the ignition switch is
turned to t he On posit ion the ESP indica tor is illu-
minated by the cluster for abou t two seconds as a
bu lb t est .
• ES P Lam p -On Me s s a ge - Ea ch time the clus-
ter receives a lamp-on messa ge from the CAB, t he
ESP in dicator will be illuminat ed. Th e indicator
rema ins illuminat ed u ntil the cluster receives a
lam p-off message fr om the CAB, or until th e ign ition
switch is tur ned to the Off posit ion, whichever occu rs
first.
8J - 16 INSTRUMENT CLUSTER VA
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