the rear brake pressure, the outlet valve is switched
off and the inlet valve is pulsed. This increases the
pressure to the rear brakes. This back-and-forth pro-
cess will continue until the required slip difference is
obtained. At the end of EBD braking (brakes
released) the fluid in the LPA drains back to the
master cylinder by switching on the outlet valve and
draining through the inlet valve check valve. At the
same time the inlet valve is switched on in case of
another brake application.
The EBD will remain functional during many ABS
fault modes. If both the red BRAKE, and amber ABS
warning indicators are illuminated, the EBD may not
be functioning.
OPERATION - TRACTION CONTROL SYSTEM
The traction control module monitors wheel speed.
During acceleration, if the module detects front
(drive) wheel slip and the brakes are not applied, the
module enters traction control mode. Traction control
operation proceeds in the following order:
(1) Close the normally open isolation valves.
(2) Start the pump/motor and supply volume and
pressure to the front (drive) hydraulic circuit. (The
pump/motor runs continuously during traction con-
trol operation.)
(3) Open and close the build and decay valves to
maintain minimum wheel slip and maximum trac-
tion.
The cycling of the build and decay valves during
traction control is similar to that during antilock
braking, except the valves work to control wheel spin
by applying the brakes, whereas the ABS function is
to control wheel skid by releasing the brakes.
If the brakes are applied at anytime during a trac-
tion control cycle, the brake lamp switch triggers the
controller to switch off traction control.
HYDRAULIC SHUTTLE VALVES
Two pressure relief hydraulic shuttle valves allow
pressure and volume to return to the master cylinder
reservoir when not consumed by the build and decay
valves. These valves are necessary because the
pump/motor supplies more volume than the system
requires.
TRACTION CONTROL LAMP
The traction control system is enabled at each igni-
tion cycle. It may be turned off by depressing the
Traction Control Off switch button when the ignition
is in the ON position. The traction control function
lamp (TRAC OFF) illuminates immediately upon
depressing the button.
The traction control function lamp illuminates dur-
ing a traction control cycle, displaying TRAC.If the CAB calculates that the brake temperatures
are high, the traction control system becomes inoper-
ative until a time-out period has elapsed. During this
ªthermo-protection mode,º the traction control func-
tion lamp illuminates TRAC OFF; note that no trou-
ble code is registered.
CAUTION
The ABS uses an electronic control module, the
CAB. This module is designed to withstand normal
current draws associated with vehicle operation.
Care must be taken to avoid overloading the CAB
circuits.
CAUTION: In testing for open or short circuits, do
not ground or apply voltage to any of the circuits
unless instructed to do so for a diagnostic proce-
dure.
CAUTION: These circuits should only be tested
using a high impedance multi-meter or the DRBIIIT
scan tool as described in this section. Power
should never be removed or applied to any control
module with the ignition in the ON position. Before
removing or connecting battery cables, fuses, or
connectors, always turn the ignition to the OFF
position.
CAUTION: The CAB 24-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
CAUTION: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of aftermarket electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, etc.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
CAUTION: When performing any service procedure
on a vehicle equipped with ABS, do not apply a
12-volt power source to the ground circuit of the
pump motor in the HCU. Doing this will damage the
pump motor and will require replacement of the
entire HCU.
CAUTION: An attempt to remove or disconnect cer-
tain system components may result in improper
system operation. Only those components with
approved removal and installation procedures in
this manual should be serviced.
RSBRAKES - ABS5-69
BRAKES - ABS (Continued)
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AUDIO SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
NO AUDIO. 1. FUSE FAULTY. 1. CHECK RADIO FUSES IN FUSE BLOCK MODULE.
REPLACE FUSES, IF REQUIRED.
2. RADIO CONNECTOR
FAULTY.2. CHECK FOR LOOSE OR CORRODED RADIO CONNECTOR.
REPAIR, IF REQUIRED.
3. WIRING FAULTY. 3. CHECK FOR BATTERY VOLTAGE AT RADIO CONNECTOR.
REPAIR WIRING, IF REQUIRED.
4. GROUND FAULTY. 4. CHECK FOR CONTINUITY BETWEEN RADIO CHASSIS AND
A KNOWN GOOD GROUND. THERE SHOULD BE
CONTINUITY. REPAIR GROUND, IF REQUIRED.
5. RADIO FAULTY. 5. EXCHANGE OR REPLACE RADIO, IF REQUIRED.
6. SPEAKERS FAULTY. 6. SEE SPEAKER DIAGNOSIS, IN THIS GROUP.
NO DISPLAY. 1. FUSE FAULTY. 1. CHECK RADIO FUSES IN FUSE BLOCK MODULE.
REPLACE FUSES, IF REQUIRED.
2. RADIO CONNECTOR
FAULTY.2. CHECK FOR LOOSE OR CORRODED RADIO CONNECTOR.
REPAIR, IF REQUIRED.
3. WIRING FAULTY. 3. CHECK FOR BATTERY VOLTAGE AT RADIO CONNECTOR.
REPAIR WIRING, IF REQUIRED.
4. GROUND FAULTY. 4. CHECK FOR CONTINUITY BETWEEN RADIO CHASSIS AND
A KNOWN GOOD GROUND. THERE SHOULD BE
CONTINUITY. REPAIR GROUND, IF REQUIRED.
5. RADIO FAULTY. 5. EXCHANGE OR REPLACE RADIO, IF REQUIRED.
NO MEMORY. 1. FUSE FAULTY. 1. CHECK IGNITION-OFF DRAW FUSE. REPLACE FUSE, IF
REQUIRED.
2. RADIO CONNECTOR
FAULTY.2. CHECK FOR LOOSE OR CORRODED RADIO CONNECTOR.
REPAIR, IF REQUIRED.
3. WIRING FAULTY. 3. CHECK FOR BATTERY VOLTAGE AT RADIO CONNECTOR.
REPAIR WIRING, IF REQUIRED.
4. GROUND FAULTY. 4. CHECK FOR CONTINUITY BETWEEN RADIO CHASSIS AND
A KNOWN GOOD GROUND. THERE SHOULD BE
CONTINUITY. REPAIR GROUND, IF REQUIRED.
5. RADIO FAULTY. 5. EXCHANGE OR REPLACE RADIO, IF REQUIRED.
POOR RADIO
RECEPTION.1. ANTENNA FAULTY. 1. SEE ANTENNA DIAGNOSIS, IN THIS GROUP. REPAIR OR
REPLACE ANTENNA, IF REQUIRED.
2. GROUND FAULTY. 2. CHECK FOR CONTINUITY BETWEEN RADIO CHASSIS AND
A KNOWN GOOD GROUND. THERE SHOULD BE
CONTINUITY. REPAIR GROUND, IF REQUIRED.
3. RADIO FAULTY. 3. EXCHANGE OR REPLACE RADIO, IF REQUIRED.
8A - 2 AUDIORS
AUDIO (Continued)
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(4) Connect battery negative cable.
QUARTER PANEL SPEAKER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove speaker grill by prying away from trim
panel.
(3) Remove speaker retaining screws (Fig. 9).
(4) Disconnect wire harness connector from
speaker.
INSTALLATION
(1) Connect the wire harness to the speaker.
(2) Install the speaker retaining screws.
(3) Install speaker grill by pressing into the trim
panel.
(4) Connect the battery negative cable.
RADIO
DIAGNOSIS AND TESTING
If the vehicle is equipped with remote radio
switches located on the backs of the steering wheel
spokes, and the problem being diagnosed is related to
one of the symptoms listed below, be certain to check
the remote radio switches and circuits as described
in this group, prior to attempting radio diagnosis or
repair.
²Stations changing with no remote radio switch
input
²Radio memory presets not working properly
²Volume changes with no remote radio switch
input
²Remote radio switch buttons taking on other
functions
²CD player skipping tracks
²Remote radio switch inoperative.
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
WARNING:
ON VEHICLES EQUIPPED WITH AIRBAGS, REFER
TO ELECTRICAL, RESTRAINTS BEFORE ATTEMPT-
ING ANY STEERING WHEEL, STEERING COLUMN,
OR INSTRUMENT PANEL COMPONENT DIAGNOSIS
OR SERVICE. FAILURE TO TAKE THE PROPER
PRECAUTIONS COULD RESULT IN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
CAUTION:
The speaker output of the radio is a ªfloating
groundº system. Do not allow any speaker lead to
short to ground, as damage to the radio may result.
(1) Check the fuse(s) in the junction block and the
Intelligent Power Module. If OK, go to Step 2. If not
OK, repair the shorted circuit or component as
required and replace the faulty fuse(s).
(2) Check for battery voltage at the fuse in the
Intelligent Power Module. If OK, go to Step 3. If not
Fig. 8 DOOR SPEAKER
1 - DOOR SPEAKER
2 - HARNESS CONNECTOR
Fig. 9 QUARTER PANEL SPEAKER
1 - SPEAKER
2 - TRIM PANEL
8A - 8 AUDIORS
DOOR MOUNTED SPEAKER (Continued)
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OK, repair the open circuit to the battery as
required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fuse in the junction
block. If OK, go to Step 4. If not OK, repair the open
circuit to the ignition switch as required.
(4) Turn the ignition switch to the OFF position.
Disconnect and isolate the battery negative cable.
Remove the radio, but do not unplug the wire har-
ness connectors. Check for continuity between the
radio chassis and a good ground. There should be
continuity. If OK, go to Step 5. If not OK, repair the
open radio chassis ground circuit as required.
(5) Connect the battery negative cable. Turn the
ignition switch to the ON position. Check for battery
voltage at the fused ignition switch output circuit
cavity of the left (gray) radio wire harness connector.
If OK, go to Step 6. If not OK, repair the open circuit
as required.
(6) Turn the ignition switch to the OFF position.
Check for battery voltage at the fused B(+) circuit
cavity of the left (gray) radio wire harness connector.
If OK, replace the faulty radio. If not OK, repair the
open circuit to the Ignition-Off Draw (IOD) fuse as
required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove cup holder.
(3) Remove trim panel above cupholder by pulling
straight out.
(4) Remove center instrument panel trim panel.
(5) Remove screws holding radio to instrument
panel.
(6) Pull radio rearward to gain access to the back
of radio (Fig. 10).
(7) Disconnect antenna cable from back of radio.
(8) Remove bolt holding ground strap to the radio.
(9) Disconnect the wire connectors from the back
of the radio.
INSTALLATION
(1) Connect wire harness to back of radio.
(2) Install bolt holding ground strap to the radio.
(3) Connect antenna cable to back of radio.
(4) Position radio into instrument panel.
(5) Install screws holding radio to instrument
panel.
(6) Install center instrument panel trim.
(7) Install trim panel above cupholder.
(8) Install cupholder.
(9) Connect battery negative cable.
RADIO NOISE SUPPRESSION
COMPONENTS
DESCRIPTION
Numerous ground straps are placed throughout the
vehicle for interference elimination (Fig. 11), (Fig.
12), (Fig. 13), (Fig. 14).
OPERATION
If receiving ignition/engine interference noise on
the radio stations, check and clean all engine and
body ground connections. Ensure all ground connec-
tions are without corrosion. Tighten properly after
cleaning.
Fig. 10 RADIO
1 - RADIO
2 - CD-PLAYER
Fig. 11 Motor Mount to Frame Rail Ground
1 - GROUND STRAP
RSAUDIO8A-9
RADIO (Continued)
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ANTENNA MODULE
DESCRIPTION
The antenna module is an electromagnetic circuit
component designed to capture and enhance RF
(Radio Frequency) signals in both the AM and FM
broadcast bands. The antenna module is mounted to
the right rear roof rail under the headliner. The mod-
ule is grounded through the mounting bracket and
fastener. The module has a two wire electrical con-
nector that connects to the integral radio antenna,located on the right rear quarter glass. There is also
an electrical connector for battery voltage and a coax
cable connector.OPERATION
The antenna module receives both AM and FM
radio signals supplied by the side window integral
radio antenna system and selectively amplifies them.
The amplified signal is then sent through the body
length coax cable to the radio input.
DIAGNOSIS AND TESTING - ANTENNA MODULE
CONDITION POSSIBLE CAUSES CORRECTION
NO AM RECEPTION,
WEAK FM RECEPTION1. Antenna module to antenna
connector open or disconnected.1. Repair open, reconnect
antenna module connector to
glass mounted antenna.
2. Coax open or disconnected. 2. Repair open, reconnect coax.
3. No battery power at antenna
module.3. Check fuse. if okay, repair
open in battery voltage circuit.
NO AM OR FM
RECEPTION1. Coax disconnected at radio. 1. Reconnect coax.
2. Coax shorted to ground. 2. Repair or Replace coax
WEAK OR NO AM/FM
RECEPTION1. Antenna Module faulty. 1. Substitute known good
module. If reception improves,
Antenna Module was faulty.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Lower headliner as necessary to access
antenna module (Fig. 2).
(3) Disconnect antenna coax cable lead and electri-
cal harness connector from antenna module.
(4) Disconnect the antenna module connector from
the quarter glass.
(5) Remove the mounting screw and the antenna
module.
INSTALLATION
(1) Install the antenna module and the mounting
fastener.
(2) Connect the antenna connector to the quarter
glass.
(3) Connect the antenna lead and electrical con-
nector to the antenna module.
(4) Raise and install headliner.
(5) Connect the battery negative cable.
Fig. 2 ANTENNA MODULE
1 - ANTENNA MODULE
2 - ANTENNA MODULE CONNECTOR
8Aa - 2 AUDIORG
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(4) Allow the battery to stabilize to open-circuit
voltage. It may take up to five minutes for the bat-
tery voltage to stabilize.
(5) Rotate the load control knob to maintain a load
equal to 50% of the CCA rating of the battery (Fig.
14). After fifteen seconds, record the loaded voltage
reading, then return the load control knob to the Off
position.
(6) The voltage drop will vary with the battery
temperature at the time of the load test. The battery
temperature can be estimated by using the ambient
temperature during the past several hours. If the
battery has been charged, boosted, or loaded a few
minutes prior to the test, the battery will be some-
what warmer. See the Load Test Temperature Table
for the proper loaded voltage reading.
LOAD TEST TEMPERATURE TABLE
Minimum VoltageTemperature
ÉF ÉC
9.6 volts 70É and above 21É and above
9.5 volts 60É 16É
9.4 volts 50É 10É
9.3 volts 40É 4É
9.1 volts 30É -1É
8.9 volts 20É -7É
8.7 volts 10É -12É
8.5 volts 0É -18É
(7) If the voltmeter reading falls below 9.6 volts, at
a minimum battery temperature of 21É C (70É F), the
battery is faulty and must be replaced.
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to thirty-five milliamperes (0.005 to 0.035 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. Up to thirty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.
Excessive IOD can be caused by:
²Electrical items left on.
²Faulty or improperly adjusted switches.
²Faulty or shorted electronic modules and compo-
nents.
²An internally shorted generator.
²Intermittent shorts in the wiring.
If the IOD is over thirty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can be
charged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw Table for more information.
Fig. 14 Load 50% CCA Rating - Note Voltage -
Typical
8F - 14 BATTERY SYSTEMRS
BATTERY (Continued)
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ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
ModuleTime Out?
(If Yes, Interval And Wake-Up Input)IODIOD After Time
Out
Radio No1to3
milliamperesN/A
Audio Power
AmplifierNoup to 1
milliampereN/A
Body Control Module
(BCM)No5.90
milliamperes
(max.)N/A
Powertrain Control
Module (PCM)No 0.95 milliampere N/A
Transmission Control
Module (TCM) 4.7L
w/45RFEYES (20 minutes, ignition on) 130 milliamperes 0.64 milliampere
ElectroMechanical
Instrument Cluster
(EMIC)No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A
(2) Disconnect the battery negative cable.
(3) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up to
three minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
(4) After about three minutes, the high-amperage
IOD reading on the multi-meter should become very
low or nonexistent, depending upon the electrical
equipment in the vehicle. If the amperage reading
remains high, remove and replace each fuse or circuit
breaker in the Intelligent Power Module (IPM), one
at a time until the amperage reading becomes very
low, or nonexistent. Refer to the appropriate wiring
information in this service manual for complete Intel-
ligent Power Module fuse, circuit breaker, and circuit
identification. This will isolate each circuit and iden-tify the circuit that is the source of the high-amper-
age IOD. If the amperage reading remains high after
removing and replacing each fuse and circuit
breaker, disconnect the wire harness from the gener-
ator. If the amperage reading now becomes very low
or nonexistent, refer to Charging System for the
proper charging system diagnosis and testing proce-
dures. After the high-amperage IOD has been cor-
rected, switch the multi-meter to progressively lower
amperage scales and, if necessary, repeat the fuse
and circuit breaker remove-and-replace process to
identify and correct all sources of excessive IOD. It is
now safe to select the lowest milliampere scale of the
multi-meter to check the low-amperage IOD.
CAUTION: Do not open any doors, or turn on any
electrical accessories with the lowest milliampere
scale selected, or the multi-meter may be damaged.
(5) Observe the multi-meter reading. The low-am-
perage IOD should not exceed thirty-five milliam-
peres (0.035 ampere). If the current draw exceeds
thirty-five milliamperes, isolate each circuit using the
fuse and circuit breaker remove-and-replace process
in Step 4. The multi-meter reading will drop to
within the acceptable limit when the source of the
excessive current draw is disconnected. Repair this
circuit as required; whether a wiring short, incorrect
switch adjustment, or a component failure is at fault.
RSBATTERY SYSTEM8F-15
BATTERY (Continued)
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²If the vehicle is equipped with an automatic
transmission, place the gearshift selector lever in the
Park position. If the vehicle is equipped with a man-
ual transmission, place the gearshift selector lever in
the Neutral position and block the clutch pedal in the
fully depressed position.
²Verify that all lamps and accessories are turned
off.
²To prevent the engine from starting, remove the
Automatic Shut Down (ASD) relay. The ASD relay is
located in the Intelligent Power Module (IPM), in the
engine compartment. See the fuse and relay layout
label affixed to the underside of the IPM cover for
ASD relay identification and location.
(1) Connect the positive lead of the voltmeter to
the battery negative terminal post. Connect the neg-
ative lead of the voltmeter to the battery negative
cable terminal clamp (Fig. 16). Rotate and hold the
ignition switch in the Start position. Observe the
voltmeter. If voltage is detected, correct the poor con-
nection between the battery negative cable terminal
clamp and the battery negative terminal post.
(2) Connect the positive lead of the voltmeter to
the battery positive terminal post. Connect the nega-
tive lead of the voltmeter to the battery positive cable
terminal clamp (Fig. 17). Rotate and hold the ignition
switch in the Start position. Observe the voltmeter. If
voltage is detected, correct the poor connection
between the battery positive cable terminal clamp
and the battery positive terminal post.(3) Connect the voltmeter to measure between the
battery positive cable terminal clamp and the starter
solenoid B(+) terminal stud (Fig. 18). Rotate and hold
the ignition switch in the Start position. Observe the
voltmeter. If the reading is above 0.2 volt, clean and
tighten the battery positive cable eyelet terminal con-
nection at the starter solenoid B(+) terminal stud.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery positive cable.
Fig. 16 Test Battery Negative Connection
Resistance - Typical
1 - VOLTMETER
2 - BATTERY
Fig. 17 Test Battery Positive Connection Resistance
- Typical
1 - VOLTMETER
2 - BATTERY
Fig. 18 Test Battery Positive Cable Resistance -
Typical
1 - BATTERY
2 - VOLTMETER
3 - STARTER MOTOR
8F - 18 BATTERY SYSTEMRS
BATTERY CABLES (Continued)
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