Light Emitting Diode (LED) behin d the cut out in the
opa que layer of the overla y causes the icon to appear
silhouetted again st a n a mber field through the tran s-
lucen t outer layer of th e overlay wh en th e indica tor
is illum ina ted from behin d by the LED, which is sol-
dered on to the inst rument cluster elect ronic circuit
board. The ABS indica tor is ser viced as a un it with
the instr umen t cluster.
OPERATION
The ABS indicator gives an indication to t he vehi-
cle operator wh en the ABS or the electr onic brake
force distribution (E BV) syst ems are faulty or inoper-
ative. Th is indica tor is cont rolled 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 ABS indica tor Ligh t Emitting 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 ABS in dicator for the followin g rea son s:
• Bulb Test - Ea ch time the ignition switch is
turned to the On position the ABS indicator is illu-
minated by the cluster for abou t two seconds as a
bu lb t est .
• AB S La m p-On Me s s ag e - Each tim e th e clus-
ter receives a lamp-on messa ge from the CAB, t he
ABS indicator will be illum inated. The in dicator
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.
The CAB cont inually monitors the ABS and EBV
circuits and sensors to decide whether the system s
are in good oper ating con dition . The CAB then sends
the pr oper la mp-on or lamp-off messages to th e
instr umen t clust er. If th e CAB sends a lamp-on mes-
sa ge a fter the bulb test, it indicates that the CAB
has detected a system ma lfun ction and/or that t he
ABS or EBV systems have become inoper ative. The
CAB will stor e a Diagnostic Trouble Code (DTC) for
any malfun ction it det ects. For proper diagnosis of
the ABS and EBV systems, the CAB, the CAN dat a
bus, the electr onic messa ge inputs to the instrumen t
cluster, or t he instr umen t clu ster cir cuitry that con-
trols the ABS indicator, a diagn ost ic scan tool is
required. Refer to the appropriate diagn ost ic infor-
mation.
ADR I N DI CAT OR
DESCRIPTION
A constant engine speed (ADR) indica tor is stan-
da rd equipm ent on a ll in st rumen t cluster s, bu t is
only function al on vehicles equipped with the
opt ional ADR switch. The ADR indicator is located
near the lower edge of th e instrument cluster, to the
right of the mu lti-funct ion indica tor display. Th e
ADR indica tor consists of th e text “ADR” im pr inted
with in a rectan gular cut out in t he opa que layer of
the in st rumen t clu st er overlay. The dark outer layer
of t he overlay prevents the indicator from being
clear ly visible when it is not illu min ated. An amber
Light Emitting Diode (LED) behin d the cut out in the
opa que layer of th e overlay causes th e t ext to appear
silhouetted again st a n a mber field through the tran s-
lucen t outer layer of th e overlay wh en th e indica tor
is illum ina ted from behin d by the LED, which is sol-
dered on to the inst rument cluster elect ronic circuit
board. The ADR i n dicator is serviced as a unit with
the instr umen t cluster.
OPERATION
The constant engine speed (ADR) in dicator gives
an in dication to the vehicle oper ator con cerning the
operat ing status of the constant engine speed (ADR)
featu re. Th e ADR in dicator is cont rolled by a tra nsis-
tor on the instrumen t cluster circuit boa rd based
upon clu st er progr amming and electron ic m essages
received by the clu st er from the Engine Con trol Mod-
ule (ECM) over the Controller Area Network (CAN)
da ta bus. The ADR indicator Light Emitting Diode
(LED) is completely controlled by the in strument
cluster logic circu it, a nd t hat logic will only a llow
this indicator to operat e when the instrument cluster
detects tha t t he ignition switch is in the On position.
Therefor e, th e LED will always be off when th e ign i-
tion switch is in any position except On. Th e LED
only illu minates when it is pr ovided a pat h to grou nd
by the instrument cluster tr ansist or. The instrument
cluster will turn on the traction control indicator for
the following rea sons:
• Co n s t a n t E n g i n e S p eed (AD R) Ind i c a to r
La m p -On Me s s ag e - Each t ime t he cluster receives
an ADR indicator lamp-on m essa ge from the ECM,
the indica tor will be illuminat ed. The indica tor is
illuminated when the ADR fea tur e ha s been acti-
vat ed with the ADR switch, an d is turn ed off when
the ADR fea ture is deactivat ed with t he ADR switch.
The ADR indica tor will be extingu ished if the ADR
featu re is tur ned off beca use the park brake has been
released or t he vehicle is in mot ion. The ADR indica-
tor will also be ext inguish ed if the service bra ke
peda l is depressed, but the ADR feat ure will auto-
matically be restored and t he in dicator illuminat ed
when the bra ke peda l is released. The indicator
8J - 10 INSTRUMENT CLUSTER VA
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