Heater AC control DODGE RAM 2002 Service User Guide

CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and air conditioning fins
should be cleaned when an accumulation of debris
has occurred. With the engine cold, apply cold water
and compressed air to the back (engine side) of the
radiator to flush the radiator and/or A/C condenser of
debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position fan shroud over the fan blades rear-
ward towards engine.
(2) Install rubber insulators to alignment dowels
at lower part of radiator.
(3) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(4) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(5) Connect both radiator hoses and install hose
clamps.
(6) Connect transmission cooler lines to radiator
tank. Inspect quick connect fittings for debris and
install until an audible ªclickº is heard. Pull apart to
verify connection.
(7) Install windshield washer reservoir tank.
(8) Position fan shroud to flanges on sides of radi-
ator. Install fan shroud mounting bolts (Fig. 41).
Tighten bolts to 6 N´m (50 in. lbs.) torque.
(9) Install metal clips to top of fan shroud.
(10) Install coolant reserve/overflow tank hose to
radiator filler neck nipple.
(11) Install coolant reserve/overflow tank to fan
shroud (fits into T-slots on shroud).
(12) Install battery negative cables.
(13) Install positive battery cable to top of radia-
tor. Tighten radiator-to-battery cable mounting nuts.
(14) Position heater controls tofull heatposition.
(15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Operate engine until it reaches normal tem-
perature. Check cooling system and automatic trans-
mission (if equipped) fluid levels.
RADIATOR PRESSURE CAP
DESCRIPTION
Radiators are equipped with a pressure cap, which
releases pressure at some point within a range of
97-124 kPa (14-18 psi). The pressure relief point (in
pounds) is engraved on top of cap.
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity.
A rubber gasket seals radiator filler neck to pre-
vent leakage. This is done to keep system under
pressure. It also maintains vacuum during coolant
cool-down allowing coolant to return from reserve/
overflow tank.
OPERATION
The cap (Fig. 43) contains a spring-loaded pressure
relief valve that opens when system pressure reaches
release range of 97-124 kPa (14-18 psi).
A vent valve in the center of cap allows a small
coolant flow through cap when coolant is below boil-
ing temperature. The valve is completely closed when
boiling point is reached. As the coolant cools, it con-
tracts and creates a vacuum in the cooling system.
This causes the vacuum valve to open and coolant in
the reserve/overflow tank to be drawn through its
connecting hose into radiator. If the vacuum valve is
stuck shut, the radiator hoses will collapse on cool-
down. Clean the vent valve (Fig. 43).
Fig. 43 Radiator Pressure Cap and Filler NeckÐ
Typical
1 - STAINLESS-STEEL SWIVEL TOP
2 - RUBBER SEALS
3 - VENT VALVE
4 - RADIATOR TANK
5 - FILLER NECK
6 - OVERFLOW NIPPLE
7 - MAIN SPRING
8 - GASKET RETAINER
7 - 64 ENGINEBR/BE
RADIATOR - 5.9L DIESEL (Continued)

(3) Remove windshield washer reservoir tank from
radiator fan shroud.
(4) Disconnect the coolant reserve/overflow tank-
to-radiator hose at the tank.
(5) Remove the four fan shroud mounting bolts at
the radiator (Fig. 47). Do not attempt to remove
shroud from vehicle at this time.
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)
MAY BE USED FOR LARGER CLAMPS. ALWAYS
WEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(6) Remove upper radiator hose at radiator.
(7) The thermal viscous fan drive is attached
(threaded) to the water pump hub shaft (Fig. 49).
Remove the fan/fan drive assembly from water pump
by turning the mounting nut counterclockwise (as
viewed from front). Threads on the fan drive are
RIGHT-HAND.A Snap-On 36 MM Fan Wrench
(number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used with Special Tool
6958 Spanner Wrench and Adapter Pins 8346 (Fig.
48) to prevent the pulley from rotating.(8) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 49) from the thermal control
fan drive.
(9) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
(10) After removing fan blade/fan drive assembly,
do notplace the thermal viscous fan drive in the
horizontal position. If stored horizontally, the silicone
fluid in the viscous drive could drain into its bearing
assembly and contaminate the bearing lubricant.
(11) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 50).
(12) Remove the lower radiator hose and heater
hose from water pump.
(13) Loosen heater hose coolant return tube
mounting bolt (Fig. 51) and remove tube from water
pump. Discard the old tube O-ring.
(14) Remove the seven water pump mounting bolts
(Fig. 52).
(15) Loosen the clamp at the water pump end of
bypass hose (Fig. 49). Slip the bypass hose from the
water pump while removing pump from vehicle. Do
not remove the clamp from the bypass hose.
(16) Discard old gasket.
CAUTION: Do not pry the water pump at timing
chain case/cover. The machined surfaces may be
damaged resulting in leaks.
Fig. 47 Typical Fan Shroud Mounting
1 - RADIATOR SUPPORT
2 - RADIATOR
3 - BOLTS (4)
4 - FAN SHROUD
Fig. 48 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
BR/BEENGINE 7 - 67
WATER PUMP - 5.9L (Continued)

Remove the fan/fan drive assembly from water pump
by turning the mounting nut counterclockwise (as
viewed from front). Threads on the fan drive are
RIGHT-HAND.A Snap-On 36 MM Fan Wrench
(number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used with Special Tool
6958 Spanner Wrench and Adapter Pins 8346 (Fig.
54) to prevent the pulley from rotating.
(7) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 55) from the thermal control
fan drive.
(8) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
After removing fan blade/fan drive assembly,do
notplace the thermal viscous fan drive in the hori-
zontal position. If stored horizontally, the silicone
fluid in the viscous drive could drain into its bearing
assembly and contaminate the bearing lubricant.
(9) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 56).
(10) Remove the radiator lower hose at water
pump.
(11) Remove heater hose at water pump fitting.
(12) Remove the seven water pump mounting bolts
(Fig. 57).
(13) Loosen the clamp at the water pump end of
bypass hose. Slip the bypass hose from the waterpump while removing pump from vehicle. Do not
remove the clamp from the bypass hose.
(14) Discard the water pump-to-timing chain/case
cover o-ring seal (Fig. 58).
Fig. 54 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
Fig. 55 Fan Blade and Viscous Fan DriveÐTypical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
Fig. 56 Belt TensionerÐ8.0L V-10 Engine
1 - PULLEY BOLT
2 - IDLER PULLEY
3 - TENSIONER PULLEY
4 - TENSIONER
5 - TENSIONER MOUNTING BOLT
7 - 70 ENGINEBR/BE
WATER PUMP - 8.0L (Continued)

(1) Disconnect negative battery cable from battery.
(2) Partially drain cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).Do not
waste reusable coolant. If the solution is clean, drain
the coolant into a clean container for reuse.
(3) Remove upper radiator hose clamp at radiator.
A special clamp tool must be used to remove the con-
stant tension clamps. Remove hose at radiator.
(4) Disconnect throttle cable from clip at radiator
fan shroud.
(5) Unplug wiring harness from A/C compressor.
(6) Remove the air cleaner assembly.
(7) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(8)5.9L V-8 LDC-Gas:The drive belt idler pulley
must be removed to gain access to one of the A/C
compressor/generator bracket mounting bolts.
Remove the idler pulley bolt and remove idler pulley
(Fig. 64).(9)5.9L HDC-Gas:The automatic belt tensioner/
pulley assembly must be removed to gain access to
one of the A/C compressor/generator bracket mount-
ing bolts. Remove the tensioner mounting bolt (Fig.
65) and remove tensioner.
(10) Remove the engine oil dipstick tube mounting
bolt at the side of the A/C-generator mounting
bracket.
(11) Disconnect throttle body control cables.
(12) Remove heater hose coolant return tube
mounting bolt (Fig. 66) (Fig. 67) and remove tube
from engine. Discard the old tube O-ring.
(13) Remove bracket-to-intake manifold bolts
(number 1 and 2 (Fig. 63).
(14) Remove remaining bracket-to-engine bolts
(Fig. 68) (Fig. 69).
Fig. 64 Idler Pulley - 5.9L V-8 LDC-Gas Engine
Fig. 65 Belt Tensioner - 5.9L HDC-Gas Engine
1 - PULLEY BOLT
2 - IDLER PULLEY
3 - TENSIONER PULLEY
4 - TENSIONER
5 - TENSIONER MOUNTING BOLT
7 - 74 ENGINEBR/BE
WATER PUMP INLET TUBE - 5.9L (Continued)

(15) Lift and position generator and A/C compres-
sor (along with their common mounting bracket) to
gain access to bypass hose. A block of wood may be
used to hold assembly in position.
(16) Loosen and position both hose clamps to the
center of bypass hose. A special clamp tool must be
used to remove the constant tension clamps. Remove
hose from vehicle.
REMOVAL - WATER PUMP BYPASS HOSE
WITHOUT AIR CONDITIONING
A water pump bypass hose (Fig. 70) is used
between the intake manifold and water pump on all
gas powered engines. To test for leaks, (Refer to 7 -
COOLING - DIAGNOSIS AND TESTING).
(1) Partially drain cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE). Do not
waste reusable coolant. If the solution is clean, drain
the coolant into a clean container for reuse.WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094). SNAP-ON CLAMP TOOL (NUMBER HPC-20)
MAY BE USED FOR LARGER CLAMPS. ALWAYS
WEAR SAFETY GLASSES WHEN SERVICING CON-
STANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(2) Loosen both bypass hose clamps and position to
the center of hose.
(3) Remove hose from vehicle.
INSTALLATION
INSTALLATION - WATER PUMP BYPASS HOSE
WITH AIR CONDITIONING
(1) Position bypass hose clamps to the center of
hose.
(2) Install bypass hose to engine.
(3) Secure both hose clamps.
(4) Install generator-A/C mounting bracket assem-
bly to engine. Tighten bolt number 1 (Fig. 63) to 41
N´m (30 ft. lbs.) torque. Tighten bolt number 2 (Fig.
63) to 28 N´m (20 ft. lbs.) torque. Tighten bracket
mounting bolts (Fig. 68) (Fig. 69) to 40 N´m (30 ft.
lbs.) torque.
(5) Install a new O-ring to the heater hose coolant
return tube (Fig. 66) (Fig. 67). Coat the new O-ring
with antifreeze before installation.
(6) Install coolant return tube and its mounting
bolt to engine (Fig. 66) (Fig. 67).
(7) Connect throttle body control cables.
(8) Install oil dipstick mounting bolt.
(9)/5.9L V-8 LDC-Gas Engine:Install idler pul-
ley. Tighten bolt to 41 N´m (30 ft. lbs.) torque.
Fig. 70 Water Pump Bypass Hose - Typical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
7 - 76 ENGINEBR/BE
WATER PUMP INLET TUBE - 5.9L (Continued)

AUDIO
TABLE OF CONTENTS
page page
AUDIO
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING - AUDIO..........2
SPECIAL TOOLS
AUDIO SYSTEMS......................4
ANTENNA BODY & CABLE
DESCRIPTION..........................4
OPERATION............................4
DIAGNOSIS AND TESTING - ANTENNA.......5
REMOVAL.............................6
INSTALLATION..........................6
RADIO CHOKE RELAY
DESCRIPTION..........................7
OPERATION............................8
DIAGNOSIS AND TESTING - RADIO CHOKE
RELAY...............................8
REMOVAL.............................8
INSTALLATION..........................9
INSTRUMENT PANEL ANTENNA CABLE
REMOVAL.............................9
INSTALLATION..........................9
RADIO
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - RADIO.........10
REMOVAL.............................11
INSTALLATION.........................11
RADIO NOISE SUPPRESSION COMPONENTS
DESCRIPTION.........................12
DIAGNOSIS AND TESTING - RADIO NOISE
SUPPRESSION COMPONENTS...........12ENGINE-TO-BODY GROUND STRAP
REMOVAL.............................12
INSTALLATION.........................13
CAB-TO- BED GROUND STRAP
REMOVAL.............................13
INSTALLATION.........................14
HEATER CORE GROUND STRAP
REMOVAL.............................14
INSTALLATION.........................14
REMOTE SWITCHES
DESCRIPTION.........................14
OPERATION...........................15
DIAGNOSIS AND TESTING - REMOTE
SWITCHES..........................15
REMOVAL.............................16
INSTALLATION.........................16
SPEAKER
DESCRIPTION.........................17
OPERATION...........................17
DIAGNOSIS AND TESTING - SPEAKER......17
A-PILLAR TWEETER SPEAKER
REMOVAL.............................18
INSTALLATION.........................19
FRONT DOOR SPEAKER
REMOVAL.............................19
INSTALLATION.........................19
REAR CAB SIDE PANEL SPEAKER
REMOVAL.............................20
INSTALLATION.........................20
REAR DOOR SPEAKER
REMOVAL.............................20
INSTALLATION.........................21
AUDIO
DESCRIPTION
An audio system is standard factory-installed
equipment on this model, unless the vehicle is
ordered with an available radio delete option. The
standard equipment audio system includes an
AM/FM/cassette (RAS sales code) receiver, and
speakers in four locations. Several combinations of
radio receivers and speaker systems are offered as
optional equipment on this model. The audio system
uses an ignition switched source of battery current so
that the system will only operate when the ignition
switch is in the On or Accessory positions. The audio
system includes the following components:²Antenna
²Clockspring (with remote radio switches only)
²Filter, choke and speaker relay (with premium
speaker system only)
²High-line or premium Central Timer Module
(CTM) (with remote radio switches)
²Radio noise suppression components
²Radio receiver
²Remote radio switches (optional with RAZ radio
receiver only)
²Speakers
Refer to Electrical, Restraints for more information
on the clockspring. Refer to Electrical, Body Control/
Central Control Module for more information on the
Central Timer Module. Refer to the appropriate wir-
ing information. The wiring information includes wir-
BR/BEAUDIO 8A - 1

assembly. Replace the faulty or damaged antenna
base and cable, if required.
TEST 3
Test 3 checks the condition of the vehicle body
ground connection. This test should be performed
with the battery positive cable removed from the bat-
tery. Disconnect both battery cables, the negative
cable first. Reconnect the battery negative cable and
perform the test as follows:
(1) Connect one ohmmeter test lead to the vehicle
fender. Connect the other test lead to the battery
negative terminal post.
(2) The resistance should be less than one ohm.
(3) If the resistance is more than one ohm, check
the braided ground strap(s) connected to the engine
and the vehicle body for being loose, corroded, or
damaged. Repair the ground strap connections, if
required.
TEST 4
Test 4 checks the condition of the ground between
the antenna base and the vehicle body as follows:
(1) Connect one ohmmeter test lead to the vehicle
fender. Connect the other test lead to the outer crimp
on the antenna coaxial cable connector.
(2) The resistance should be less then one ohm.
(3) If the resistance is more then one ohm, clean
and/or tighten the antenna base to fender mounting
hardware.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Reach under the passenger side of the instru-
ment panel near the right cowl side inner panel to
disengage the coaxial cable connector from the
retainer clip located on the bottom of the heater-A/C
housing (Fig. 2).
(3) Remove the foam tape to access the coaxial
cable connector. Disconnect the connector by pulling
it apart while twisting the metal connector halves.
Do not pull on the cable.
(4) Securely tie a suitable length of cord or twine
to the antenna half of the coaxial cable connector.
This cord will be used to pull or ªfishº the cable back
into position during installation.
(5) Reach above the Powertrain Control Module
(PCM) on the right side of the dash panel in the
engine compartment to disengage the antenna coax-
ial cable grommet from the hole in the dash panel
(Fig. 3).
(6) Pull the antenna coaxial cable out of the pas-
senger compartment and into the engine compart-
ment through the hole in the dash panel.(7) Raise the sleeve on the antenna mast far
enough to access and unscrew the antenna mast from
the antenna body (Fig. 4).
(8) Remove the antenna cap nut using an antenna
nut wrench (Special Tool C-4816) (Fig. 5).
(9) Remove the antenna adapter from the top of
the fender.
(10) Lower the antenna body and cable assembly
through the top of the fender.
(11) Pull the antenna body and cable out through
the opening between the right cowl side outer panel
and the top of the fender, while feeding the antenna
coaxial cable out of the engine compartment through
the hole in the right cowl side reinforcement.
(12) Untie the cord or twine from the antenna
body and cable coaxial cable connector, leaving the
cord or twine in the place of the cable through the
vehicle.
(13) Remove the antenna body and cable from the
vehicle.
INSTALLATION
(1) Tie the end of the cord or twine that was used
during instrument panel antenna cable removal
securely to the connector on the end of the antenna
cable being installed into the instrument panel. This
cord will be used to pull or ªfishº the cable back into
position.
Fig. 2 Antenna Coaxial Cable Connector
1 - RETAINER CLIP
2 - TO RADIO
3 - TO ANTENNA
4 - FOAM TAPE
8A - 6 AUDIOBR/BE
ANTENNA BODY & CABLE (Continued)

RADIO NOISE SUPPRESSION
COMPONENTS
DESCRIPTION
Radio Frequency Interference (RFI) and Electro-
Magnetic Interference (EMI) noise suppression is
accomplished primarily through circuitry internal to
the radio receivers. These internal suppression
devices are only serviced as part of the radio receiver.
External suppression devices that are used on this
vehicle to control RFI or EMI noise include the fol-
lowing:
²Radio antenna base ground
²Radio receiver chassis ground wire or strap
²Engine-to-body ground straps
²Cab-to-bed ground strap
²Heater core ground strap
²Resistor-type spark plugs
²Radio suppression-type secondary ignition wir-
ing.
For more information on the spark plugs and sec-
ondary ignition components, refer to Electrical, Igni-
tion Control.
DIAGNOSIS AND TESTING - RADIO NOISE
SUPPRESSION COMPONENTS
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.
For complete circuit diagrams, refer to the appro-
priate 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 connec-
tors, splices and grounds. Inspect the ground paths
and connections at the following locations:
²Blower motor
²Cab-to-bed ground strap
²Electric fuel pump
²Engine-to-body ground straps
²Generator
²Ignition module
²Heater core ground strap
²Radio antenna base ground
²Radio receiver chassis ground wire or strap
²Wiper motor.If the source of RFI or EMI noise is identified as a
component on the vehicle (i.e., generator, blower
motor, etc.), the ground path for that component
should be checked. If excessive resistance is found in
any ground circuit, clean, tighten, or repair the
ground circuits or connections to ground as required
before considering any component replacement.
For service and inspection of secondary ignition
components, refer to Electrical, Ignition Control.
Inspect the following secondary ignition system com-
ponents:
²Distributor cap and rotor
²Ignition coil
²Spark plugs
²Spark plug wire routing and condition.
Reroute the spark plug wires or replace the faulty
components as required.
If the source of the RFI or EMI noise is identified
as two-way mobile radio or telephone equipment,
check the equipment installation for the following:
²Power connections should be made directly to
the battery, and fused as closely to the battery as
possible.
²The antenna should be mounted on the roof or
toward the rear of the vehicle. Remember that mag-
netic antenna mounts on the roof panel can adversely
affect the operation of an overhead console compass,
if the vehicle is so equipped.
²The antenna cable should be fully shielded coax-
ial cable, should be as short as is practical, and
should be routed away from the factory-installed
vehicle wire harnesses whenever possible.
²The antenna and cable must be carefully
matched to ensure a low Standing Wave Ratio
(SWR).
Fleet vehicles are available with an extra-cost RFI-
suppressed Powertrain Control Module (PCM). This
unit reduces interference generated by the PCM on
some radio frequencies used in two-way radio com-
munications. However, this unit will not resolve com-
plaints of RFI in the commercial AM or FM radio
frequency ranges.
ENGINE-TO-BODY GROUND
STRAP
REMOVAL
(1) Remove the screw that secures the engine-to-
body ground strap eyelet to the dash panel (Fig. 10).
(2) Remove the screw that secures the engine-to-
body ground strap eyelet to the back of the engine
cylinder head (Fig. 11) or (Fig. 12).
8A - 12 AUDIOBR/BE

NOTE: ECM Outputs:
After inputs are received by the ECM, certain sen-
sors, switches and components are controlled or reg-
ulated by the ECM. These are consideredECM
Outputs.These outputs are for:
²CCD bus (+) circuits
²CCD bus (-) circuits
²CKP and APPS outputs to the PCM
²Data link connection for DRB scan tool
²Five volt sensor supply
²Fuel injection pump
²Fuel injection pump relay
²(FPCM) Fuel Pump Control Module
²Fuel transfer (lift) pump
²Intake manifold air heater relays #1 and #2 con-
trol circuits
²Malfunction indicator lamp (Check engine lamp)
²Oil pressure gauge/warning lamp
²PCM
²Wait-to-start warning lamp
²Water-In-Fuel (WIF) warning lamp
REMOVAL
The ECM is bolted to the engine block behind the
fuel filter (Fig. 16).(1) Record any Diagnostic Trouble Codes (DTC's)
found in the PCM or ECM.
To avoid possible voltage spike damage to either
the Powertrain Control Module (PCM) or ECM, igni-
tion key must be off, and negative battery cables
must be disconnected before unplugging ECM con-
nectors.
(2) Disconnect both negative battery cables at both
batteries.
(3) Remove 50±way electrical connector bolt at
ECM (Fig. 16). Note: Connector bolt is female 4mm
hex head. To remove bolt, use a ball-hex bit or ball-
hex screwdriver such as Snap-Ont4mm SDABM4
(5/32º may also be used). As bolt is being removed,
very carefully remove connector from ECM.
(4) Remove three ECM mounting bolts and remove
ECM from vehicle.
INSTALLATION
Do not apply paint to back of ECM. Poor ground
will result.
(1) Clean ECM mounting points at engine block.
(2) Position ECM to engine block and install 3
mounting bolts. Tighten bolts to 24 N´m (18 ft. lbs.).
(3) Check pin connectors in ECM and 50±way con-
nector for corrosion or damage. Repair as necessary.
(4) Clean pins in 50±way electrical connector with
a quick-dry electrical contact cleaner.
(5) Very carefully install 50±way connector to
ECM. Tighten connector hex bolt.
(6) Install battery cables.
(7)Turn key to ON position. Without starting
engine, slowly press throttle pedal to floor and
then slowly release. This step must be done
(one time) to ensure accelerator pedal position
sensor calibration has been learned by ECM. If
not done, possible DTC's may be set.
(8) Use DRB scan tool to erase any stored compan-
ion DTC's from PCM.
Fig. 16 Engine Control Module (ECM) Location and
Mounting
1 - ENGINE CONTROL MODULE (ECM)
2 - HEX HEADED BOLT
3 - 50-WAY CONNECTOR
4 - FUEL TRANSFER PUMP
5 - MOUNTING BOLTS (3)
8E - 14 ELECTRONIC CONTROL MODULESBR/BE
ENGINE CONTROL MODULE (Continued)

POWERTRAIN CONTROL
MODULE
DESCRIPTION
DESCRIPTION - PCM
The Powertrain Control Module (PCM) is located
in the engine compartment (Fig. 17). The PCM is
referred to as JTEC.
DESCRIPTION - MODES OF OPERATION
As input signals to the Powertrain Control Module
(PCM) change, the PCM adjusts its response to the
output devices. For example, the PCM must calculate
different injector pulse width and ignition timing for
idle than it does for wide open throttle (WOT).
The PCM will operate in two different modes:
Open Loop and Closed Loop.
During Open Loop modes, the PCM receives input
signals and responds only according to preset PCM
programming. Input from the oxygen (O2S) sensors
is not monitored during Open Loop modes.
During Closed Loop modes, the PCM will monitor
the oxygen (O2S) sensors input. This input indicates
to the PCM whether or not the calculated injector
pulse width results in the ideal air-fuel ratio. This
ratio is 14.7 parts air-to-1 part fuel. By monitoring
the exhaust oxygen content through the O2S sensor,
the PCM can fine tune the injector pulse width. This
is done to achieve optimum fuel economy combined
with low emission engine performance.
The fuel injection system has the following modes
of operation:
²Ignition switch ON²Engine start-up (crank)
²Engine warm-up
²Idle
²Cruise
²Acceleration
²Deceleration
²Wide open throttle (WOT)
²Ignition switch OFF
The ignition switch On, engine start-up (crank),
engine warm-up, acceleration, deceleration and wide
open throttle modes are Open Loop modes. The idle
and cruise modes, (with the engine at operating tem-
perature) are Closed Loop modes.
IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system
is activated by the ignition switch, the following
actions occur:
²The PCM pre-positions the idle air control (IAC)
motor.
²The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic fuel
strategy.
²The PCM monitors the engine coolant tempera-
ture sensor input. The PCM modifies fuel strategy
based on this input.
²Intake manifold air temperature sensor input is
monitored.
²Throttle position sensor (TPS) is monitored.
²The auto shutdown (ASD) relay is energized by
the PCM for approximately three seconds.
²The fuel pump is energized through the fuel
pump relay by the PCM. The fuel pump will operate
for approximately three seconds unless the engine is
operating or the starter motor is engaged.
²The O2S sensor heater element is energized via
the ASD relay. The O2S sensor input is not used by
the PCM to calibrate air-fuel ratio during this mode
of operation.
ENGINE START-UP MODE
This is an Open Loop mode. The following actions
occur when the starter motor is engaged.
The PCM receives inputs from:
²Battery voltage
²Engine coolant temperature sensor
²Crankshaft position sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Starter motor relay
²Camshaft position sensor signal
The PCM monitors the crankshaft position sensor.
If the PCM does not receive a crankshaft position
sensor signal within 3 seconds of cranking the
engine, it will shut down the fuel injection system.
Fig. 17 PCM Location
1 - PCM MOUNTING BOLTS (3)
2 - POWERTRAIN CONTROL MODULE (PCM)
3 - (3) 32±WAY CONNECTORS
BR/BEELECTRONIC CONTROL MODULES 8E - 15