CONDITION POSSIBLE CAUSES CORRECTION
COOLANT COLOR 1. Coolant color is not necessarily
an indication of adequate corrosion
or temperature protection. Do not
rely on coolant color for determining
condition of coolant.1. Check the freeze point of the
coolant. (Refer to 7 - COOLING/
ENGINE/COOLANT - DIAGNOSIS
AND TESTING) Adjust the ethylene
glycol-to-water ratio as necessary.
COOLANT LEVEL CHANGES IN
COOLANT BOTTLE.
TEMPERATURE GAUGE IS IN
NORMAL RANGE.1. Level changes are to be
expected as coolant volume
fluctuates with engine temperature.
The coolant level will also drop as
the system removes air from a
recent filling.1. A normal condition. No repair is
necessary.
Refer to (Fig. 1) when using the TEMPERATURE
GAUGE INDICATION DIAGNOSIS CHART.
TEMPERATURE GAUGE INDICATION DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READING
IS INCONSISTENT (FLUCTUATES,
CYCLES OR IS ERRATIC).1. Normal reaction to fan and/or
thermostat cycle (Fig. 1 ),
Examples B and C. During cold
weather operation with the heater
blower in the high position, the
gauge reading may drop slightly
(Fig. 1 ), Example D. Fluctuation is
also influenced by outside
temperature and heavy loads (Fig.
1 ), Example E.1. A normal condition. No correction
is necessary.
2. Gauge reading rises when
vehicle is brought to a stop after
heavy use (engine still running)
(Fig. 1 ), Example F.2. A normal condition. No correction
is necessary. Gauge reading should
return to normal range (Fig. 1 ),
Example A, after vehicle is driven.
3. Gauge reading high after
restarting a warmed-up (hot)
engine.3. A normal condition. No correction
is necessary. The gauge should
return to normal range (Fig. 1 ),
Example A, after a few minutes of
engine operation.
4. Temperature gauge or engine
coolant temperature sensor
defective or shorted. Also, corroded
or loose wiring in the electrical
circuit.4. Check operation of gauge or
engine coolant temperature sensor
and repair, if necessary.
RSENGINE7-17
ENGINE (Continued)
OPERATION
The data link connector (diagnostic connector)
links the DRB scan tool with the Powertrain Control
Module (PCM). Refer to On-Board Diagnostics in the
General Diagnosis section of this group.
FRONT CONTROL MODULE
DESCRIPTION
The Front Control Module (FCM) is a micro con-
troller based module located in the engine compart-
ment. This FCM mates to the power distribution
center to form the Integrated Power Module (IPM).
The IPM connects directly to the battery and pro-
vides the primary means of circuit protection and
power distribution for all vehicle electrical systems.
The FCM controls power to some of these vehicle sys-
tems electrical and electromechanical loads based on
inputs received from hard wired switch inputs and
data received on the Programmable Communications
Interface (PCI) data bus.
For information on the IPM, (Refer to 8 - ELEC-
TRICAL/POWER DISTRIBUTION/INTEGRATED
POWER MODULE - DESCRIPTION)
OPERATION
As messages are sent over the Programmable Com-
munications Interface (PCI) data bus, the Front Con-
trol Module (FCM) reads these messages and controls
power to some of the vehicles electrical systems by
completing the circuit to ground (low side driver) or
completing the circuit to 12 volt power (high side
driver).
The following functions arecontrolledby the
Front Control Module:²Accessory Relay Actuation
²Brake Transmission Shift Interlock Functions
(BTSI)
²Diesel Cabin Heater (Diesel Engine Vehicles)
²Electronic Back Light (EBL) Rear Defogger
²Electronic Transaxle (Gasoline engine Vehicles)
²Front and Rear Blower Motor Relay Actuation
²Front Fog Lamp Relay Actuation
²Front Washer Motor
²Front Windshield Wiper ªHIº & ªLOº Relay
Actuation
²Front Windshield Wiper ªONº Relay Actuation
²Headlamp Power with Voltage Regulation
²Horn Relay Actuation
²Headlamp Washer Relay Actuation
²Name Brand Speaker (NBS) Relay Actuation
²Occupant Restraint Controller Voltage
²Park Lamp Relay Actuation
²Rear Washer Motor
²Side Airbag Voltage
The following inputs areReceived/Monitoredby
the Front Control Module:
²Ambient Temperature Sensing
²Back-Up switch
²Brake Fluid Level
²B+ Connection Detection
²Engine Crank Signal (Diesel Engine Vehicles)
²Horn Input
²Ignition Switch Start Only
²Ignition Switch Run and Start Only
²Stop Lamp Sense
²Washer Fluid Level
²Windshield Wiper Park
DIAGNOSIS AND TESTING - FRONT CONTROL
MODULE
The Front Control Module (FCM) is a printed cir-
cuit board based module with a on-board micro-pro-
cessor. The FCM interfaces with other electronic
modules in the vehicle via the Programmable Com-
munications Interface (PCI) data bus. In order to
obtain conclusive testing the PCI data bus and all of
the electronic modules that provide inputs to, or
receive outputs from the FCM must be checked. All
PCI communication faults must be resolved prior to
further diagnosing any front control module related
issues.
The FCM was designed to be diagnosed with an
appropriate diagnostic scan tool, such as the DRB
IIIt. The most reliable, efficient, and accurate means
to diagnose the front control module requires the use
of a DRB IIItscan tool and the proper Body Diag-
nostic Procedures manual.
Before any testing of the FCM is attempted, the
battery should be fully charged and all wire harness
Fig. 4 DATA LINK CONNECTOR
RSELECTRONIC CONTROL MODULES8E-7
DATA LINK CONNECTOR (Continued)
GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The Generator Decoupler is a one way clutch (Fig.
3). It is attached to the generator and replaces the
standard pulley. It is a non-serviceable item and is to
be replaced as an assembly. It is a dry operation (no
grease or lubricants). The operation of it is not tem-
perature sensitive and has a low sensitivity to elec-
trical load.
OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to
help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER PULLEY
CONDITION VERIFICATION PROCEDURE POSSIBLE CAUSES CORRECTION
Does not drive
generator (Generator
not Charging)1. Start engine and allow
engine to idle.Clutch failure Replace Decoupler
2.Verify generator pulley is
rotating.
3. View generator internal fins
thru generator housing.
4. Fins either do not rotate or
rotate very erratic.
5. Rotate decoupler pulley in
clockwise direction then
quickly rotate in
counterclockwise direction to
see if clutch engages.
Noise from generator
at engine shut down.1. Start engine and allow
engine to idle.Defective decoupler
pulley bearing.Replace decoupler pulley.
2. Shutdown engine and listen
to generator.
3. Noise heard just as engine
stops. Sounds like a click.
4. Remove accessory drive
belt.
5. Verify rotation in
counterclock wise direction is
rough.
Fig. 3 GENERATOR DECOUPLER 3.3/3.8L
RSCHARGING8F-25
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the PDC fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the starter solenoid field coils. There should be
continuity between the cavity for relay terminal 87
and the starter solenoid terminal at all times. If OK,
go to Step 4. If not OK, repair the open circuit to the
starter solenoid as required.
(4) The coil battery terminal (85) is connected to
the electromagnet in the relay. It is energized when
the ignition switch is held in the Start position and
the clutch pedal is depressed (manual trans). Check
for battery voltage at the cavity for relay terminal 86
with the ignition switch in the Start position and the
clutch pedal is depressed (manual trans), and no
voltage when the ignition switch is released to the
On position. If OK, go to Step 5. If not OK, check for
an open or short circuit to the ignition switch and
repair, if required. If the circuit to the ignition switch
is OK, see the Ignition Switch Test procedure in this
group.
(5) The coil ground terminal (86) is connected to
the electromagnet in the relay. It is grounded by the
PCM if the conditions are right to start the car. For
automatic trans. cars the PCM must see Park Neu-
tral switch low and near zero engine speed (rpm).
For manual trans. cars the PCM only needs to see
near zero engine speed (rpm) and low clutch inter-
lock input and see near zero engine speed (rpm). To
diagnose the Park Neutral switch of the trans range
sensor refer to the transaxle section. Check for conti-
nuity to ground while the ignition switch is in the
start position and if equipped the clutch pedal
depressed. If not OK and the vehicle has an auto-
matic trans. verify Park Neutral switch operation. If
that checks OK check for continuity between PCM
and the terminal 86. Repair open circuit as required.
Also check the clutch interlock switch operation if
equipped with a manual transmission. If OK, the
PCM may be defective.
SAFETY SWITCHES
For diagnostics of the Transmission Range Sensor,
refer to the Transaxle section for more information.
If equipped with Clutch Interlock/Upstop Switch,
refer to Diagnosis and Testing in the Clutch section.
IGNITION SWITCH
After testing starter solenoid and relay, test igni-
tion switch and wiring. Refer to the Ignition Section
or Wiring Diagrams for more information. Check all
wiring for opens or shorts, and all connectors for
being loose or corroded.
BATTERY
For battery diagnosis and testing, refer to the Bat-
tery section for procedures.
ALL RELATED WIRING AND CONNECTORS
Refer to Wiring Diagrams for more information.
DIAGNOSIS AND TESTING - FEED CIRCUIT
RESISTANCE TEST
Before proceeding with this operation, review Diag-
nostic Preparation and Starter Feed Circuit Tests.
The following operation will require a voltmeter,
accurate to 1/10 of a volt.
CAUTION: Ignition and Fuel systems must be dis-
abled to prevent engine start while performing the
following tests.
(1) To disable the Ignition and Fuel systems, dis-
connect the Automatic Shutdown Relay (ASD). The
ASD relay is located in the Power Distribution Cen-
ter (PDC). Refer to the PDC cover for proper relay
location.
(2) Gain access to battery terminals.
(3) With all wiring harnesses and components
properly connected, perform the following:
(a) Connect the negative lead of the voltmeter to
the battery negative post, and positive lead to the
battery negative cable clamp. Rotate and hold the
ignition switch in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between cable clamp and post.
(b) Connect positive lead of the voltmeter to the
battery positive post, and negative lead to the bat-
tery positive cable clamp. Rotate and hold the igni-
tion switch key in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between the cable clamp and post.
(c) Connect negative lead of voltmeter to battery
negative terminal, and positive lead to engine
block near the battery cable attaching point.
Rotate and hold the ignition switch in the START
position. If voltage reads above 0.2 volt, correct
poor contact at ground cable attaching point. If
voltage reading is still above 0.2 volt after correct-
ing poor contacts, replace ground cable.
(4) Connect positive voltmeter lead to the starter
motor housing and the negative lead to the battery
negative terminal. Hold the ignition switch key in
8F - 32 STARTINGRS
STARTING (Continued)
(11) Install accessory drive belt, refer to the Cool-
ing System section for proper procedures. (12) Install the right front lower splash shield.
(13) Lower vehicle.
(14) Install wiring harness to the oil dip stick tube
(15) Connect battery negative cable.
(16) Verify generator output rate.
GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The Generator Decoupler is a one way clutch (Fig.
11). It is attached to the generator and replaces the
standard pulley. It is a non-serviceable item and is to
be replaced as an assembly. It is a dry operation (no
grease or lubricants). The operation of it is not tem-
perature sensitive and has a low sensitivity to elec-
trical load.
OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER PULLEY
CONDITION VERIFICATION PROCEDURE POSSIBLE
CAUSESCORRECTION
Does not drive generator
(Generator not Charging) 1. Start engine and allow engine to idle. Clutch failure Replace Decoupler
2.Verify generator pulley is rotating.
3. View generator internal fins thru
generator housing.
4. Fins either do not rotate or rotate very
erratic.
5. Rotate decoupler pulley in clockwise
direction then quickly rotate in
counterclockwise direction to see if clutch
engages.
Noise from
generator at engine
shut down. 1. Start engine and allow engine to idle. Defective decoupler
pulley bearing.Replace decoupler
pulley.
2. Shutdown engine and listen to generator.
3. Noise heard just as engine stops.
Sounds like a click.
4. Remove accessory drive belt.
5. Verify rotation in counterclock wise
direction is rough.
Fig. 11 GENERATOR DECOUPLER 3.3/3.8L
RS CHARGING8Fs-27
GENERATOR (Continued)
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3. (3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the starter solenoid field coils. There should be
continuity between the cavity for relay terminal 87
and the starter solenoid terminal at all times. If OK,
go to Step 4. If not OK, repair the open circuit to the
starter solenoid as required. (4) The coil battery terminal (85) is connected to
the electromagnet in the relay. It is energized when
the ignition switch is held in the Start position and
the clutch pedal is depressed (manual trans). Check
for battery voltage at the cavity for relay terminal 86
with the ignition switch in the Start position and the
clutch pedal is depressed (manual trans), and no
voltage when the ignition switch is released to the
On position. If OK, go to Step 5. If not OK, check for
an open or short circuit to the ignition switch and
repair, if required. If the circuit to the ignition switch
is OK, see the Ignition Switch Test procedure in this
group. (5) The coil ground terminal (86) is connected to
the electromagnet in the relay. It is grounded by the
PCM if the conditions are right to start the car. For
automatic trans. cars the PCM must see Park Neu-
tral switch low and near zero engine speed (rpm).
For manual trans. cars the PCM only needs to see
near zero engine speed (rpm) and low clutch inter-
lock input and see near zero engine speed (rpm). To
diagnose the Park Neutral switch of the trans range
sensor refer to the transaxle section. Check for conti-
nuity to ground while the ignition switch is in the
start position and if equipped the clutch pedal
depressed. If not OK and the vehicle has an auto-
matic trans. verify Park Neutral switch operation. If
that checks OK check for continuity between PCM
and the terminal 86. Repair open circuit as required.
Also check the clutch interlock switch operation if
equipped with a manual transmission. If OK, the
PCM may be defective.
SAFETY SWITCHES
For diagnostics of the Transmission Range Sensor,
refer to the Transaxle section for more information. If equipped with Clutch Interlock/Upstop Switch,
refer to Diagnosis and Testing in the Clutch section.
IGNITION SWITCH
After testing starter solenoid and relay, test igni-
tion switch and wiring. Refer to the Ignition Section
or Wiring Diagrams for more information. Check all
wiring for opens or shorts, and all connectors for
being loose or corroded.
BATTERY
For battery diagnosis and testing, refer to the Bat-
tery section for procedures.
ALL RELATED WIRING AND CONNECTORS
Refer to Wiring Diagrams for more information.
DIAGNOSIS AND TESTING - FEED CIRCUIT
RESISTANCE TEST
Before proceeding with this operation, review Diag-
nostic Preparation and Starter Feed Circuit Tests.
The following operation will require a voltmeter,
accurate to 1/10 of a volt.
CAUTION: Ignition and Fuel systems must be dis-
abled to prevent engine start while performing the
following tests.
(1) To disable the Ignition and Fuel systems, dis-
connect the Automatic Shutdown Relay (ASD). The
ASD relay is located in the Power Distribution Cen-
ter (PDC). Refer to the PDC cover for proper relay
location. (2) Gain access to battery terminals.
(3) With all wiring harnesses and components
properly connected, perform the following: (a) Connect the negative lead of the voltmeter to
the battery negative post, and positive lead to the
battery negative cable clamp. Rotate and hold the
ignition switch in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between cable clamp and post. (b) Connect positive lead of the voltmeter to the
battery positive post, and negative lead to the bat-
tery positive cable clamp. Rotate and hold the igni-
tion switch key in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between the cable clamp and post. (c) Connect negative lead of voltmeter to battery
negative terminal, and positive lead to engine
block near the battery cable attaching point.
Rotate and hold the ignition switch in the START
position. If voltage reads above 0.2 volt, correct
poor contact at ground cable attaching point. If
voltage reading is still above 0.2 volt after correct-
ing poor contacts, replace ground cable.
(4) Connect positive voltmeter lead to the starter
motor housing and the negative lead to the battery
negative terminal. Hold the ignition switch key in
the START position. If voltage reads above 0.2 volt,
correct poor starter to engine ground. (a) Connect the positive voltmeter lead to the
battery positive terminal, and negative lead to bat-
tery cable terminal on starter solenoid. Rotate and
hold the ignition switch in the START position. If
voltage reads above 0.2 volt, correct poor contact at
8Fs - 34 STARTINGRS
STARTING (Continued)
used to read and troubleshoot these Diagnostic Trou-
ble Codes (DTC). Refer to the Body Diagnostic Man-
ual for a complete list of diagnostic routines.
For additional information refer to Power Liftgate
Operation. For a complete system wiring schematic
refer to Wiring Diagrams. For system operationinstructions refer to the vehicles owner manual.
Refer to the Body section of the service manual
for additional information on liftgate components
such as the prop rods, hinges, door alignment and
striker alignment.
WARNING: BE CERTAIN TO READ ALL WARNINGS
AND CAUTIONS (NOTED BELOW) IN POWER LIFT-
GATE SYSTEM OPERATION BEFORE ATTEMPTING
ANY SERVICE OF THE POWER LIFTGATE SYSTEM
OR COMPONENTS.
OPERATION
With the push of a power liftgate open/close com-
mand switch (key fob or overhead console mounted) a
signal is sent out on the J1850 PCI Data Bus circuit.
This signal is detected at the body control module
(BCM). The BCM then sends a signal out on the
J1850 PCI Data Bus circuit to the power liftgate
module. The power liftgate module then signals the
power liftgate motor to start an open or close cycle,
depending on what position the liftgate is in open or
closed.
During a liftgate open or close cycle, if the power
liftgate module detects sufficient resistance to liftgate
travel, such as an obstruction in the liftgates path,
the power liftgate control module will immediately
stop the liftgate movement and reverse travel to the
full open or closed position. The ability for the power
liftgate module to detect resistance to liftgate travel
is accomplished by hall effect sensors, drive motor
speed and pinch sensors (tape switches).
The power liftgate control module has the ability to
learn. Anytime the liftgate is opened or closed using
the power liftgate system the module learns from its
cycle. If a replacement power liftgate component is
installed or a liftgate adjustment is made, the mod-
ule will relearn the effort and/or time required to
open or close the door. This learn cycle can be per-
formed with a Diagnostic Scan Tool, such as the
DRB IIItor with a complete cycle of the liftgate,
using any one of the command switches. Refer to
Standard Procedures in this section for detailed
instructions.
The power liftgate system is designed with a num-
ber of system inhibitors. These inhibitors are neces-
sary for safety and / or feasibility of the power
liftgate system. Refer to power liftgate system inhib-
itors noted below:
POWER LIFTGATE SYSTEM INHIBITORS
²The Power Liftgate may not operate in extreme
temperatures. These extreme temperatures will be
approximately -12É F (-24.4É C) on the low side and
143É F (61.6É C) for the high side. A chime/thermister
Fig. 2 KEY FOB
1 - Left Sliding Door Switch
2 - Right Sliding Door Switch
3 - Liftgate Switch
Fig. 3 LIFTGATE FUSE LOCATION
RSPOWER LIFTGATE SYSTEM8N-3
POWER LIFTGATE SYSTEM (Continued)
Body Diagnostic Manual for a complete list of diag-
nostic routines.
NOTE: It may be possible to generate Sliding Door
Diagnostic Trouble Codes during normal power
sliding door operation. Refer to the Body Diagnos-
tic Manual for a complete list of diagnostic routines.
For additional information, (Refer to 8 - ELECTRI-
CAL/POWER DOORS - OPERATION). For a com-
plete power sliding door system wiring schematic,
refer to Wiring Diagrams. For power sliding door sys-
tem operation instructions, refer to the vehicle owner
manual.
WARNING: BE CERTAIN TO READ ALL WARNINGS
AND CAUTIONS IN POWER SLIDING DOOR OPER-
ATION BEFORE ATTEMPTING ANY SERVICE OF
POWER SLIDING DOOR SYSTEM OR COMPO-
NENTS.
OPERATION
With the push of a power sliding door open/close
command switch (key fob, overhead console or B-pil-
lar mounted) a signal is sent out to the Body Control
Module (BCM). The BCM then sends a signal out on
the PCI Data Bus circuit (J1850) to the power sliding
door module. The power sliding door module then
signals the power sliding door latch to release the
door to the unlatched and movable position. The
motor then starts an open cycle.
During the door open cycle, if the power sliding
door module detects sufficient resistance to doortravel, such as an obstruction in the door's path, the
power sliding door module will immediately stop door
movement and reverse door travel to the full open or
closed position. The ability for the power sliding door
module to detect resistance to door travel is accom-
plished by hall effect sensors and the door motor
speed.
The power sliding door control module has the abil-
ity to learn. Anytime a door is opened or closed using
the power sliding door system the module learns
from its cycle. If a replacement power sliding door
component is installed or a door adjustment is made,
the module must re-learn the effort required to open
or close the door. A learn cycle can be performed with
a Diagnostic Scan Tool, such as the DRB IIIt, or with
a complete cycle of the door, using any one of the
command switches. Refer to Standard Procedures in
this section for detailed instructions.
The power sliding door system is designed with a
number of system inhibitors. These inhibitors are
necessary for safety and/or feasibility of the power
sliding door system. See the power sliding door sys-
tem inhibitors noted below:
POWER SLIDING DOOR SYSTEM INHIBITORS
²The power sliding door must be in thefullopen
or closed position in order for the power sliding door
system to start a cycle. If the door is not in this posi-
tion (based on the input from the full open, pawl or
ratchet switches) the door control module will not
respond to command switch inputs.
²The vehicles transmission must be inpark or
neutralin order for the power sliding door system to
start a cycle.
²The vehicles child lockout switch must be in the
ªUNLOCKEDº position in order for the power sliding
door systems B-pillar switches to function.
²If multiple obstacles are detected during the
same power open or close cycle the power sliding
door may go into full manual mode.
²If severe Diagnostic Trouble Codes (DTC) are
stored in the power sliding door control module the
power sliding door may go into full manual mode.
²Due to the high pressure created in the passen-
ger compartment with the blower motor on high, the
power sliding door may not complete a power close
cycle unless a window is cracked, allowing the pres-
sure to escape. This situation will only be experi-
enced on some vehicles, or vehicles with brand new
side door weather seals installed. Refer to the Side
Door Adjustment procedure in the Standard Proce-
dures section of this group.
²The vehicles fuel tank filler door must be in the
closed position. Due to the sliding door interference
with the open fuel tank filler door, mechanical link-
age prevents the side door from opening and striking
Fig. 3 Power Side Door Fuse Location
RSPOWER SLIDING DOOR SYSTEM8N-21
POWER SLIDING DOOR SYSTEM (Continued)