2002 CHRYSLER TOWN AND COUNTRY Grounds

RADIATOR FAN RELAY
DESCRIPTION
The low and high speed fan relays are mounted to
the upper radiator support above the charge air
cooler (Fig. 25).
OPERATION
The cooling system uses two fans. Both fans oper-
ate at two different speeds, low and high. Depending
on engine coolant temperature and A/C system high
side pressure, the fans operate at either low or high.
The ignition switch supplies voltage to the coil side of
the relay. When the ECM grounds the coil side of the
relay, the contacts close and the battery supplies
power to the fans.
COOLANT SYSTEM HOSES
REMOVAL
REMOVAL - UPPER RADIATOR HOSE
WARNING: THE WARNING WORDS ªDO NOT OPEN
HOTº ON THE RADIATOR PRESSURE CAP IS A
SAFETY PRECAUTION. WHEN HOT, PRESSURE
BUILDS UP IN COOLING SYSTEM. TO PREVENT
SCALDING OR INJURY, THE RADIATOR CAP
SHOULD NOT BE REMOVED WHILE THE SYSTEM
IS HOT OR UNDER PRESSURE.(1) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(2) Drain cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(3) Remove upper radiator hose (Fig. 26).
REMOVAL - LOWER RADIATOR HOSE
WARNING: THE WARNING WORDS ªDO NOT OPEN
HOTº ON THE RADIATOR PRESSURE CAP IS A
SAFETY PRECAUTION. WHEN HOT, PRESSURE
BUILDS UP IN COOLING SYSTEM. TO PREVENT
SCALDING OR INJURY, THE RADIATOR CAP
SHOULD NOT BE REMOVED WHILE THE SYSTEM
IS HOT OR UNDER PRESSURE.
(1) Drain cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(2) Remove lower radiator hose (Fig. 26).
Fig. 25 RELAY LOCATIONS
1 - GLOW PLUG RELAY
2 - UPPER RADIATOR SUPPORT
3 - CHARGE AIR COOLER OUTLET HOSE
4 - RADIATOR FAN RELAYS
5 - UPPER RADIATOR HOSE
6 - EGR SOLENOID
Fig. 26 UPPER AND LOWER RADIATOR HOSES
1 - COOLANT BYPASS HOSE
2 - RADIATOR ASSEMBLY
3 - UPPER RADIATOR HOSE
4 - COOLING FAN
5 - LOWER RADIATOR HOSE
6 - CHARGE AIR COOLER
7 - RADIATOR BRACKET
RGENGINE7a-29
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information and location views for the various wire
harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING 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.
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.
8A - 2 AUDIORS
AUDIO (Continued)
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NOTE: Use care when inserting CD changer so that
cable is not pinched or trapped against instrument
panel.
(3) Install screws holding CD changer.
(4) Reconnect the battery negative cable.
INSTRUMENT PANEL
ANTENNA CABLE
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING 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.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove glove box (Refer to 23 - BODY/IN-
STRUMENT PANEL/GLOVE BOX - REMOVAL).
(3) Disconnect extension cable end from antenna
cable end.
(4) Disconnect cable hanger clip from HVAC unit.
(5) Remove radio as necessary to gain access to
extension cable (Refer to 8 - ELECTRICAL/AUDIO/
RADIO - REMOVAL).
(6) Disconnect extension cable from back of radio.
(7) Remove extension cable from vehicle.
INSTALLATION
(1) Install extension cable to vehicle.
(2) Connect extension cable to back of radio.
(3) Install radio (Refer to 8 - ELECTRICAL/AU-
DIO/RADIO - INSTALLATION).
(4) Connect cable hanger clip to HVAC unit.
(5) Connect extension cable end to antenna cable
end.
(6) Install glove box (Refer to 23 - BODY/INSTRU-
MENT PANEL/GLOVE BOX - INSTALLATION).
(7) Connect the battery negative cable.
QUARTER GLASS INTEGRAL
ANTENNA - EXPORT
DESCRIPTION
The quarter glass integral antenna element is
bonded to the right rear quarter glass and is replaced
with the glass assembly only (Fig. 7).
OPERATION
The integral antenna receives RF (Radio Frequen-
cies) and sends them to the antenna module for
amplification.
DIAGNOSIS AND TESTING - QUARTER GLASS
INTEGRAL ANTENNA - EXPORT
The antenna grid pattern is divided into two sepa-
rate patterns. Each terminal connects to a separate
grid pattern, one for AM and the other for FM.
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. To detect breaks in the
integral antenna elements, the following procedure is
required:
(1) Disconnect the antenna module connector from
the antenna terminals on the glass.
(2) Using an ohmmeter, place a lead on one of the
terminals and check each end of the grid pattern con-
nected to this terminal for continuity. If continuity is
not present, move one lead through the grid in pro-
gression starting at the terminal with the other lead
on the terminal until continuity is lost. Repeat pro-
cedure for the other terminal. A break in the antenna
grid can be repaired using a Mopar Rear Window
Defogger Repair Kit (Part Number 4267922) or
equivalent. (Refer to 8 - ELECTRICAL/HEATED
GLASS/WINDSHIELD GRID - STANDARD PROCE-
DURE).
Fig. 7 QUARTER GLASS INTEGRAL ANTENNA
1 - REAR QUARTER GLASS
2 - ANTENNA
8A - 8 AUDIORS
CD CHANGER (Continued)
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RADIO
DIAGNOSIS AND TESTING - RADIO
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING 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.
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
If the vehicle is equipped with remote radio
switches located on the back 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.
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
Integrated Power Module (IPM). 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
(IPM). If OK, go to Step 3. If not 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.
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 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 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. 8).
(7) Disconnect the antenna cable by pulling the
locking antenna connector away from the radio (Fig.
9).
(8) Disconnect bolt holding ground strap to the
radio (if equipped).
Fig. 8 RADIO
1 - RADIO
2 - CD-PLAYER
RSAUDIO8A-9
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REMOTE SWITCHES
DESCRIPTION
A remote radio control switch option is available on
some models. Two rocker-type switches are mounted
on the back (instrument panel side) of the steering
wheel spokes (Fig. 10). The switch on the left spoke
is the seek switch and has seek up, seek down, and
preset station advance functions. The switch on the
right spoke is the volume control switch and has vol-
ume up, and volume down functions. The switch on
the right spoke also includes a ªmodeº control that
allows the driver to sequentially select AM radio, FM
radio, cassette player, CD player or CD changer (if
equipped).
OPERATION
These switches are resistor multiplexed units that
are hard-wired to the Body Control Module (BCM)
through the clockspring. The BCM sends the proper
messages on the Programmable Communications
Interface (PCI) data bus network to the radio
receiver. For diagnosis of the BCM or the PCI data
bus, the use of a DRB IIItscan tool and the proper
Diagnostic Procedures manual are recommended. For
more information on the operation of the remote
radio switch controls, refer to the owner's manual in
the vehicle glove box.
DIAGNOSIS AND TESTING - REMOTE
SWITCHES
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING 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.
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the airbag system capac-
itor to discharge before further service.
(2) Remove the remote radio switch(es) from the
steering wheel. (Refer to 8 - ELECTRICAL/AUDIO/
REMOTE SWITCHES - REMOVAL).
(3) Use an ohmmeter to check the switch resis-
tance as shown in the Remote Radio Switch Test
table (Fig. 11).
Fig. 10 Remote Radio Switch Operational View
1 - PRESET SEEK
2 - SEEK UP
3 - VOLUME UP
4 - MODE
5 - VOLUME DOWN
6 - SEEK DOWN
Fig. 11 Remote Radio Switches
1 - WHITE REAR SWITCH
2 - BLACK REAR SWITCH
RSAUDIO8A-11
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Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
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) If all speakers are inoperative, check the radio
fuses in the junction block. If OK, go to Step 2. If not
OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(2) Turn the ignition switch to the ON position.
Turn the radio receiver ON. Adjust the balance and
fader control controls to check the performance of
each individual speaker. Note the speaker locations
that are not performing correctly. Go to Step 3.
(3) Turn the radio receiver OFF. Turn the ignition
OFF. Disconnect and isolate the battery negative
cable. Remove the radio receiver.
(4) Check both the speaker feed (+) circuit and
return (-) circuit cavities for the inoperative speaker
at the radio receiver wire harness connector for con-
tinuity to ground. There should be no continuity. If
OK, go to Step 5. If not OK, repair the shorted
speaker feed (+) and/or return (-) circuits(s) to the
speaker as required.
(5) Disconnect wire harness connector at the inop-
erative speaker. Check for continuity between the
speaker feed (+) circuit cavities of the radio receiver
wire harness connector. Repeat the check between
the speaker return (-) circuit cavities of the radio
receiver wire harness connector and the speaker wire
harness connector. In each case, there should be con-
tinuity. If OK, replace the faulty speaker. If not OK,
repair the open speaker feed (+) and/or return (-) cir-
cuits(s) as required.
REMOVAL
D-PILLAR SPEAKER
(1)Disconnect and isolate the battery negative cable.
(2) Remove rear header trim (right side speaker).
(3) Remove jack cover (left side speaker).
(4) Remove liftgate scuff plate.
(5) Remove upper seat belt bolt. (Refer to 8 -
ELECTRICAL/RESTRAINTS/SEAT BELT OUT-
BOARD FRONT - REMOVAL).(6) Partially remove quarter trim panel to access
the D-pillar speaker.
(7) Slide the speaker from the retainer (Fig. 12).
(8) Disconnect the wire harness connector from the
speaker.
FRONT DOOR SPEAKER
(1)Disconnect and isolate the battery negative cable.
(2)Remove the front door trim panel. (Refer to 23 -
BODY/DOOR - FRONT/TRIM PANEL - REMOVAL).
(3) Remove the speaker mounting screws (Fig. 13).
(4) Disconnect wire harness connector and remove
speaker from door.
Fig. 12 D-PILLAR SPEAKER
1 - SPEAKER
2 - RETAINER
3 - TRIM PANEL
Fig. 13 DOOR SPEAKER
1 - SPEAKER
2 - WIRE HARNESS CONNECTOR
RSAUDIO8A-13
SPEAKER (Continued)
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(a) BCM has two battery feeds at pin 1 and pin
5 of the 6±way connector.
(b) Pin 5 of the (BX2) 32 way connector of the
BCM for ignition feed.
(c) Check voltage (PX2) connector, pin 34 for 12v.
(d) If voltage OK, go to step Step 3
(e) If NO voltage repair as necessary. Refer to
the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, further details on
wire harness routing and retention, as well as pin-
out and location views for the various wire harness
connectors, splices and grounds.
(3) Check driver's seat belt buckle switch input
(form ORC) for a closed circuit when not buckled. If
input not seen, look for open in wiring or switch. The
switch is grounded when belt is not buckled.
(4) Verify PCI data bus communication between
ORC and BCM.
NO FASTEN SEAT BELT LAMP WHEN IGNITION
SWITCH IS TURNED ON.
(1) Check for burned out lamp.
(2) Using a voltmeter check for voltage at the clus-
ter conncctor:
(a) Pin 2 of the mechanical instrument cluster
for battery feed.
(b) Pin 11 of the mechanical instrument cluster
for ignition voltage.
(3) Repair as necessary.
FASTEN SEAT BELT LAMP OR TONE CONTINUES
FOR MORE THAN 10 SECONDS AFTER SEAT
BELTS ARE FASTENED AND DRIVER'S DOOR IS
CLOSED.
Refer to the proper Body Diagnostic Procedures
manual.
NO TONE WHEN PARK OR HEADLAMPS ARE ON
AND DRIVER'S DOOR IS OPEN.
Make sure ignition is in lock position with the key
removed.
(1) Check the BCM DTC's and BCM sensors to
verify the door is open. Repair as necessary.
(2) Actuate Chime (BCM actuates).
(3) Inspect BCM connectors and wires for proper
connection.
(4) Measure with a voltmeter the voltage (12v) on
BCM connector (PX2) pin 34 with harness connected.
DIAGNOSIS AND TESTING - DOME LAMP ON
CHIME
The dome lamp on chime will warn the driver that
the dome lamps have been left on.When the ignition is OFF and the key is out of the
ignition:
²Driver's door OPEN (door ajar switch is closed to
ground) and
²Dome lamps are ON (dome lamp switch is closed
to ground),
The chime will sound continuously until the driv-
ers door is closed, dome lamps turned OFF or until
the battery protection time out of 15 minutes has
expired. Chime rate: 168 to 192 chimes per minute.
DIAGNOSIS AND TESTING - ENGINE
TEMPERATURE CRITICAL CHIME
The engine temperature critical chime will warn
the driver that the vehicle's engine is overheating.
While monitoring the coolant temperature, the Pow-
ertrain Control Module (PCM) will send on the PCI
data bus as engine temperature every 1.376 seconds
to the cluster. The MIC calculates engine tempera-
ture and determines if a warning should occur. This
feature is functional only with the Ignition Switch in
the Run/Start position.
When the engine temperature reaches 122ÉC
(252ÉF) the MIC requests a chime from the BCM and
the engine temperature lamp comes ON. The MIC
turns OFF the lamp when the engine temperature
reaches 117ÉC (242ÉF). The MIC will chime continu-
ously (request from the BCM). The chime will turn
OFF after four minutes or when the temperature
reaches 117ÉC (242ÉF), which ever occurs first.
DIAGNOSIS AND TESTING - EXTERIOR LAMPS
ON CHIME
The exterior lamp on chime will warn the driver
that the exterior lights have been left on.
With the ignition switch OFF/key out of ignition:
²Driver's door is open (door ajar switch is closed
to ground)
²Parking lamps or headlamps ON (parking lamp
switch is closed to ground)
The chime will sound until lights are turned OFF,
driver's door closed or until the battery protection
time out of 3 minutes has expired.
Chime rate: 168 to 192 chimes per minute.
To test the exterior lamps left on function:
²Turn ignition off
²Remove ignition key
²Turn exterior lamps on with driver's door open.
Chime should sound until lamps are turned off or
driver's door is closed.
DIAGNOSIS AND TESTING - KEY-IN IGNITION
CHIME
The key-in ignition chime will act as a warning to
the driver that the ignition key has been left in the
8B - 2 CHIME/BUZZERRS
CHIME/BUZZER (Continued)
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(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
(G) Generator Lamp Illuminated
GENERIC
SCAN TOOL
CODEDRB SCAN TOOL DISPLAY DESCRIPTION OF DIAGNOSTIC TROUBLE CODE
P2008 Short Runner Valve Solenoid Circuit An open or shorted condition detected in the short runner
tuning valve control circuit.
P2302 Ignition Coil Secondary #1 Circuit
P2305 Ignition Coil Secondary #2 Circuit
P2308 Ignition Coil Secondary #3 Circuit
P2311 Ignition Coil Secondary #4 Circuit
P2314 Ignition Coil Secondary #5 Circuit
P2317 Ignition Coil Secondary #6 Circuit
P2320 Ignition Coil Secondary #7 Circuit
P2323 Ignition Coil Secondary #8 Circuit
P2503 Charging System Voltage Low Charging system voltage below minimum acceptable voltage.
OPERATION - SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits within the Powertrain Control Module (PCM).
OPERATION - SCI RECEIVE - PCM INPUT
SCI Receive is the serial data communication
receive circuit for the DRB scan tool. The Powertrain
Control Module (PCM) receives data from the DRB
through the SCI Receive circuit.
OPERATION - IGNITION SENSE - PCM INPUT
The ignition sense input informs the Powertrain
Control Module (PCM) that the ignition switch is in
the crank or run position.
OPERATION - PCM GROUND
Ground is provided through multiple pins of the
PCM connector. Depending on the vehicle there may
be as many as three different ground pins. There are
power grounds and sensor grounds.
The power grounds are used to control the ground
side of any relay, solenoid, ignition coil or injector.
The signal ground is used for any input that uses
sensor return for ground, and the ground side of any
internal processing component.
The SBEC III case is shielded to prevent RFI and
EMI. The PCM case is grounded and must be firmly
attached to a good, clean body ground.
Internally all grounds are connected together, how-
ever there is noise suppression on the sensor ground.
For EMI and RFI protection the case is also
grounded separately from the ground pins.
OPERATION
OPERATION - 8-VOLT SUPPLY - PCM OUTPUT
The PCM supplies 8 volts to the crankshaft posi-
tion sensor, camshaft position sensor.
OPERATION - 5 VOLT SUPPLY - PCM OUTPUT
The PCM supplies 5 volts to the following sensors:
²A/C pressure transducer
²Engine coolant temperature sensor
²Manifold absolute pressure sensor
²Throttle position sensor
²Linear EGR solenoid
²Battery temperature
²Knock sensor
STANDARD PROCEDURE - OBTAINING
DIAGNOSTIC TROUBLE CODES
BULB CHECK
Key on: Bulb illuminated until vehicle starts, as
long as all once per trip (readiness) monitors com-
pleted. If monitors havenotbeen completed, then:
Key on: bulb check for about 8 seconds, lamp then
flashes if once per trip (readiness) monitors havenot
been completed until vehicle is started, then MIL is
extinguished.
OBTAINING DTC'S USING DRB SCAN TOOL
(1) Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
RSELECTRONIC CONTROL MODULES8E-25
POWERTRAIN CONTROL MODULE (Continued)
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