engine oil DODGE RAM 2001 Service Manual PDF

STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES - WITH RADIATOR
IN-TANK TRANSMISSION OIL COOLER
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
The only recommended procedure for flushing cool-
ers and lines is to use Tool 6906-B Cooler Flusher.
WARNING: WEAR PROTECTIVE EYEWEAR THAT
MEETS THE REQUIREMENTS OF OSHA AND ANSI
Z87.1±1968. WEAR STANDARD INDUSTRIAL RUB-
BER GLOVES.
KEEP LIGHTED CIGARETTES, SPARKS, FLAMES,
AND OTHER IGNITION SOURCES AWAY FROM THE
AREA TO PREVENT THE IGNITION OF COMBUSTI-
BLE LIQUIDS AND GASES. KEEP A CLASS (B) FIRE
EXTINGUISHER IN THE AREA WHERE THE
FLUSHER WILL BE USED.
KEEP THE AREA WELL VENTILATED.
DO NOT LET FLUSHING SOLVENT COME IN CON-
TACT WITH YOUR EYES OR SKIN: IF EYE CONTAM-
INATION OCCURS, FLUSH EYES WITH WATER FOR
15 TO 20 SECONDS. REMOVE CONTAMINATED
CLOTHING AND WASH AFFECTED SKIN WITH
SOAP AND WATER. SEEK MEDICAL ATTENTION.
(1) Remove cover plate filler plug on Tool 6906-B.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.(2) Reinstall filler plug on Tool 6906-B.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.
NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
NOTE: The converter drainback valve must be
removed and an appropriate replacement hose
installed to bridge the space between the transmis-
sion cooler line and the cooler fitting. Failure to
remove the drainback valve will prevent reverse
flushing the system. A suitable replacement hose
can be found in the adapter kit supplied with the
flushing tool.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
(8) Turn pump OFF.
(9) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(10) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(11) Place CLEAR suction line into a one quart
container of MopartATF +4, type 9602, Automatic
Transmission Fluid.
(12) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(13) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
STANDARD PROCEDURE - FLUSHING COOLER
AND TUBES - WITHOUT RADIATOR IN-TANK
TRANSMISSION OIL COOLER
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
(1) Remove cover plate filler plug on Tool 6906B.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
Fig. 4 Automatic Transmission Oil CoolerÐ8.0L
Engine
1 - RADIATOR SUPPORT
2 - OIL COOLER MOUNTING BOLTS
3 - TRANSMISSION OIL COOLER
4 - TRANSMISSION OIL COOLER LINES
BR/BETRANSMISSION 7 - 83
TRANS COOLER - 8.0L (Continued)

erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.
(2) Reinstall filler plug on Tool 6906B.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.
NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
NOTE: The converter drainback valve must be
removed and an appropriate replacement hose
installed to bridge the space between the transmis-
sion cooler line and the cooler fitting. Failure to
remove the drainback valve will prevent reverse
flushing the system. A suitable replacement hose
can be found in the adapter kit supplied with the
flushing tool.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Remove the transmission oil cooler from the
vehicle. (Refer to 7 - COOLING/TRANSMISSION/
TRANS COOLER - REMOVAL)
(8) Remove the transmission oil cooler thermostat.
(Refer to 7 - COOLING/TRANSMISSION/TRANS
COOLER - DISASSEMBLY)
(9) Re-install the thermostat cover onto the oil
cooler and install the snap-ring.
(10) Re-connect the oil cooler to the transmission
cooler lines.
(11) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
NOTE: This flushes the bypass circuit of the cooler
only.
(12) Turn pump OFF.
(13) Remove the thermostat cover from the oil
cooler.
(14) Install Special Tool Cooler Plug 8414 into the
transmission oil cooler.
(15) Re-install the thermostat cover onto the oil
cooler and install the snap-ring.
(16) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
NOTE: This flushes the main oil cooler core pas-
sages only.
(17) Turn pump OFF.
(18) Remove the thermostat cover from the oil
cooler.(19) Remove Special Tool Cooler Plug 8414 from
the transmission oil cooler.
(20) Install a new thermostat spring, thermostat,
cover, and snap-ring into the transmission oil cooler.
(Refer to 7 - COOLING/TRANSMISSION/TRANS
COOLER - ASSEMBLY)
(21) Install the transmission oil cooler onto the
vehicle. (Refer to 7 - COOLING/TRANSMISSION/
TRANS COOLER - INSTALLATION)
(22) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(23) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(24) Place CLEAR suction line into a one quart
container of MopartATF +4, type 9602, Automatic
Transmission fluid.
(25) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(26) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
REMOVAL
(1) Place a drain pan under the oil cooler lines.
(2) Disconnect the two transmission lines from the
oil cooler by loosening the two worm gear clamps and
pulling the rubber hoses off of the oil cooler tubes
(Fig. 5). Plug all oil cooler lines to prevent oil leak-
age.
(3) Remove three oil cooler-to-radiator support
mounting bolts (Fig. 5).
(4) Remove the oil cooler and line assembly from
the vehicle.
Fig. 5 Transmission Oil CoolerÐ8.0L Engine
1 - RADIATOR SUPPORT
2 - OIL COOLER MOUNTING BOLTS
3 - TRANSMISSION OIL COOLER
4 - TRANSMISSION OIL COOLER LINES
7 - 84 TRANSMISSIONBR/BE
TRANS COOLER - 8.0L (Continued)

INSTALLATION
(1) Install the oil cooler and cooler line assembly to
the vehicle.
(2) Install three mounting bolts and tighten to 6
N´m (50 in. lbs.) torque.
(3) Connect the transmission cooling lines to the
oil cooler by pushing the rubber hoses onto the oil
cooler tubes. Tighten the worm gear clomps to 2 N´m
(18 in. lbs.)
(4) Start the engine and check all fittings for
leaks.
(5) Check the fluid level in the automatic trans-
mission (Refer to 21 - TRANSMISSION/TRAN-
SAXLE/AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
TRANS COOLER - 5.9L DIESEL
DESCRIPTION
All diesel models equipped with an automatic
transmission are equipped with both a main water-
to-oil cooler and a separate air-to-oil cooler. Both cool-
ers are supplied as standard equipment on diesel
engine powered models when equipped with an auto-
matic transmission.
The main water-to-oil transmission oil cooler is
mounted to a bracket on the turbocharger side of the
engine (Fig. 6).
The air-to-oil cooler is located in front of and to the
left side of the radiator (Fig. 7).
OPERATION
The transmission oil is routed through the main
cooler first, then the auxiliary cooler where addi-
tional heat is removed from the transmission oil
before returning to the transmission.
STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES - WITH RADIATOR
IN-TANK TRANSMISSION OIL COOLER
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
The only recommended procedure for flushing cool-
ers and lines is to use Tool 6906-B Cooler Flusher.
Fig. 6 Transmission Water-To-Oil CoolerÐDiesel
EngineÐTypical
1 - TRANSMISSION WATER-TO-OIL COOLER
Fig. 7 Auxiliary Transmission Oil CoolerÐDiesel
Engine
1 - CHARGE AIR COOLER (INTERCOOLER)
2 - QUICK-CONNECT FITTINGS (2)
3 - MOUNTING NUTS (2)
4 - MOUNTING BOLT
5 - TRANSMISSION OIL COOLER
BR/BETRANSMISSION 7 - 85
TRANS COOLER - 8.0L (Continued)

(9) Re-install the thermostat cover onto the oil
cooler and install the snap-ring.
(10) Re-connect the oil cooler to the transmission
cooler lines.
(11) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
NOTE: This flushes the bypass circuit of the cooler
only.
(12) Turn pump OFF.
(13) Remove the thermostat cover from the oil
cooler.
(14) Install Special Tool Cooler Plug 8414 into the
transmission oil cooler.
(15) Re-install the thermostat cover onto the oil
cooler and install the snap-ring.
(16) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
NOTE: This flushes the main oil cooler core pas-
sages only.
(17) Turn pump OFF.
(18) Remove the thermostat cover from the oil
cooler.
(19) Remove Special Tool Cooler Plug 8414 from
the transmission oil cooler.
(20) Install a new thermostat spring, thermostat,
cover, and snap-ring into the transmission oil cooler.
(Refer to 7 - COOLING/TRANSMISSION/TRANS
COOLER - ASSEMBLY)
(21) Install the transmission oil cooler onto the
vehicle. (Refer to 7 - COOLING/TRANSMISSION/
TRANS COOLER - INSTALLATION)
(22) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(23) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(24) Place CLEAR suction line into a one quart
container of MopartATF +4, type 9602, Automatic
Transmission fluid.
(25) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(26) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
REMOVALÐAIR TO OIL COOLER
(1) Remove front bumper.
(2) Place a drain pan under the oil cooler.
(3) Raise the vehicle.
(4) Disconnect the oil cooler quick-connect fittings
from the transmission lines.(5) Remove the charge air cooler-to-oil cooler bolt
(Fig. 8).
(6) Remove two mounting nuts.
(7) Remove the oil cooler and line assembly
towards the front of vehicle. Cooler must be rotated
and tilted into position while removing.
REMOVALÐWATER TO OIL COOLER
CAUTION: If a leak should occur in the water-to-oil
cooler mounted to the side of the engine block,
engine coolant may become mixed with transmis-
sion fluid. Transmission fluid may also enter engine
cooling system. Both cooling system and transmis-
sion should be drained and inspected in case of oil
cooler leakage.
(1) Disconnect both battery negative cables.
(2) Remove air cleaner assembly and air cleaner
intake hoses.
(3) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(4) Disconnect coolant lines from cooler.
(5) Disconnect transmission oil lines from cooler.
Plug cooler lines to prevent oil leakage.
(6) Remove oil cooler mounting straps (Fig. 9).
Fig. 8 Auxiliary Transmission Oil CoolerÐDiesel
Engine
1 - CHARGE AIR COOLER (INTERCOOLER)
2 - QUICK-CONNECT FITTINGS (2)
3 - MOUNTING NUTS (2)
4 - MOUNTING BOLT
5 - TRANSMISSION OIL COOLER
BR/BETRANSMISSION 7 - 87
TRANS COOLER - 5.9L DIESEL (Continued)

(7) Lift oil cooler off of mounting bracket.
(8) If replacing cooler, make sure to transfer con-
verter drain back valve to new cooler.INSTALLATIONÐAIR TO OIL COOLER
(1) Carefully position the oil cooler assembly to the
vehicle.
(2) Install two nuts and one bolt. Tighten to 11
N´m (95 in. lbs.) torque.
(3) Connect the quick-connect fittings to the trans-
mission cooler lines.
(4) Install front bumper.
(5) Start the engine and check all fittings for
leaks.
(6) Check the fluid level in the automatic trans-
mission (Refer to 21 - TRANSMISSION/TRAN-
SAXLE/AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
INSTALLATION
(1) Position oil cooler on bracket.
(2) Install mounting straps.
(3) Connect transmission oil lines to cooler.
(4) Connect coolant hoses to cooler.
(5) Connect battery negative cables.
(6) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(7) Check transmission oil level and fill as neces-
sary (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 47RE/FLUID - STANDARD
PROCEDURE).
(8) Install air cleaner assembly and air cleaner
intake hoses.
Fig. 9 Transmission Water-To- Oil CoolerÐDiesel
1 - TRANSMISSION WATER-TO-OIL COOLER
7 - 88 TRANSMISSIONBR/BE
TRANS COOLER - 5.9L DIESEL (Continued)

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).
(3) For the right side only on vehicles equipped
with a 3.9L, 5.2L or 5.9L engine, remove the nut thatsecures the engine-to-body ground strap eyelet to the
right rear valve cover stud.
(4) Remove the engine-to-body ground strap from
the engine compartment.INSTALLATION
(1) Position the engine-to-body ground strap to the
back of the engine cylinder head.
(2) Install and tighten the screw that secures the
engine-to-body ground strap eyelet to the back of the
engine cylinder head. Tighten the screw to 3.9 N´m
(35 in. lbs.).
Fig. 10 Engine-To-Body Ground
1 - SCREWS (2)
2 - GROUND STRAPS
Fig. 11 Engine-To-Body Ground Strap Remove/
Install - V6 & V8 Engine
1 - GROUND STRAP
2 - NUT
3 - GROUND STRAP
4 - SCREW
5 - SCREW
BR/BEAUDIO 8A - 13
RADIO NOISE SUPPRESSION COMPONENTS (Continued)

ENGINE CONTROL MODULE
DESCRIPTION - ECM
The ECM is bolted to the left side of the engine
behind the fuel filter (Fig. 14). It is a separate com-
ponent and can be serviced. The FPCM is internal to
the fuel injection pump (Fig. 15) and cannot be ser-
viced.
OPERATION - ECM
The main functions of the Engine Control Module
(ECM) and Fuel Injection Pump Control Module
(FPCM) are to electrically control the fuel system.
The Powertrain Control Module (PCM)does not
controlthe fuel system.
The ECM can adapt its programming to meet
changing operating conditions.If the ECM has
been replaced, flashed or re-calibrated, the
ECM must learn the Accelerator Pedal Position
Sensor (APPS) idle voltage. Failure to learn
this voltage may result in unnecessary diagnos-
tic trouble codes. Refer to ECM Removal/Instal-
lation for learning procedures.
The ECM receives input signals from various
switches and sensors. Based on these inputs, the
ECM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to asECM Outputs.The sensors
and switches that provide inputs to the ECM are
consideredECM Inputs.NOTE: ECM Inputs:
²Accelerator Pedal Position Sensor (APPS) Volts
²APPS Idle Validation Switches #1 and #2
²Battery voltage
²Camshaft Position Sensor (CMP)
²CCD bus (+) circuits
²CCD bus (-) circuits
²Crankshaft Position Sensor (CKP)
²Data link connection for DRB scan tool
²(FPCM) Fuel Injection Pump Control Module
²Engine Coolant Temperature (ECT) sensor
²Ground circuits
²Intake manifold Air Temperature (IAT) sensor
²Manifold Air Pressure Sensor (Boost Pressure
Sensor)
²Oil pressure sensor
²PCM
²Power Take Off (PTO)
²Power ground
²Sensor return
²Signal ground
²Water-In-Fuel (WIF) sensor
Fig. 14 Engine Control Module (ECM) Location
1 - ENGINE CONTROL MODULE (ECM)
2 - HEX HEADED BOLT
3 - 50-WAY CONNECTOR
4 - FUEL TRANSFER PUMP
5 - MOUNTING BOLTS (3)
Fig. 15 Fuel Injection Pump Control Module (FPCM)
Location
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
BR/BEELECTRONIC CONTROL MODULES 8E - 13

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.
POWERTRAIN CONTROL
MODULE
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.
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)

²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal (in the distribu-
tor)
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
Based on these inputs the following occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
the injection sequence and injector pulse width by
turning the ground circuit to each individual injector
on and off.
²The PCM adjusts engine idle speed through the
idle air control (IAC) motor and adjusts ignition tim-
ing.
²The PCM operates the A/C compressor clutch
through the clutch relay. This is done if A/C has been
selected by the vehicle operator and requested by the
A/C thermostat.
²When engine has reached operating tempera-
ture, the PCM will begin monitoring O2S sensor
input. The system will then leave the warm-up mode
and go into closed loop operation.
IDLE MODE
When the engine is at operating temperature, this
is a Closed Loop mode. At idle speed, the PCM
receives inputs from:
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
²Battery voltage
²Crankshaft position sensor
²Engine coolant temperature sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal (in the distribu-
tor)
²Battery voltage
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Oxygen sensors
Based on these inputs, the following occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
injection sequence and injector pulse width by turn-
ing the ground circuit to each individual injector on
and off.
²The PCM monitors the O2S sensor input and
adjusts air-fuel ratio by varying injector pulse width.
It also adjusts engine idle speed through the idle air
control (IAC) motor.
²The PCM adjusts ignition timing by increasing
and decreasing spark advance.²The PCM operates the A/C compressor clutch
through the clutch relay. This happens if A/C has
been selected by the vehicle operator and requested
by the A/C thermostat.
CRUISE MODE
When the engine is at operating temperature, this
is a Closed Loop mode. At cruising speed, the PCM
receives inputs from:
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
²Battery voltage
²Engine coolant temperature sensor
²Crankshaft position sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal (in the distribu-
tor)
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Oxygen (O2S) sensors
Based on these inputs, the following occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then adjust
the injector pulse width by turning the ground circuit
to each individual injector on and off.
²The PCM monitors the O2S sensor input and
adjusts air-fuel ratio. It also adjusts engine idle
speed through the idle air control (IAC) motor.
²The PCM adjusts ignition timing by turning the
ground path to the coil on and off.
²The PCM operates the A/C compressor clutch
through the clutch relay. This happens if A/C has
been selected by the vehicle operator and requested
by the A/C thermostat.
ACCELERATION MODE
This is an Open Loop mode. The PCM recognizes
an abrupt increase in throttle position or MAP pres-
sure as a demand for increased engine output and
vehicle acceleration. The PCM increases injector
pulse width in response to increased throttle opening.
DECELERATION MODE
When the engine is at operating temperature, this
is an Open Loop mode. During hard deceleration, the
PCM receives the following inputs.
²Air conditioning select signal (if equipped)
²Air conditioning request signal (if equipped)
²Battery voltage
²Engine coolant temperature sensor
²Crankshaft position sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
8E - 16 ELECTRONIC CONTROL MODULESBR/BE
POWERTRAIN CONTROL MODULE (Continued)

²Camshaft position sensor signal (in the distribu-
tor)
²Park/neutral switch (gear indicator signalÐauto.
trans. only)
²Vehicle speed sensor
If the vehicle is under hard deceleration with the
proper rpm and closed throttle conditions, the PCM
will ignore the oxygen sensor input signal. The PCM
will enter a fuel cut-off strategy in which it will not
supply a ground to the injectors. If a hard decelera-
tion does not exist, the PCM will determine the
proper injector pulse width and continue injection.
Based on the above inputs, the PCM will adjust
engine idle speed through the idle air control (IAC)
motor.
The PCM adjusts ignition timing by turning the
ground path to the coil on and off.
WIDE OPEN THROTTLE MODE
This is an Open Loop mode. During wide open
throttle operation, the PCM receives the following
inputs.
²Battery voltage
²Crankshaft position sensor
²Engine coolant temperature sensor
²Intake manifold air temperature sensor
²Manifold absolute pressure (MAP) sensor
²Throttle position sensor (TPS)
²Camshaft position sensor signal (in the distribu-
tor)
During wide open throttle conditions, the following
occurs:
²Voltage is applied to the fuel injectors with the
ASD relay via the PCM. The PCM will then control
the injection sequence and injector pulse width by
turning the ground circuit to each individual injector
on and off. The PCM ignores the oxygen sensor input
signal and provides a predetermined amount of addi-
tional fuel. This is done by adjusting injector pulse
width.
²The PCM adjusts ignition timing by turning the
ground path to the coil on and off.
IGNITION SWITCH OFF MODE
When ignition switch is turned to OFF position,
the PCM stops operating the injectors, ignition coil,
ASD relay and fuel pump relay.
DESCRIPTION - 5 VOLT SUPPLIES
Two different Powertrain Control Module (PCM)
five volt supply circuits are used; primary and sec-
ondary.
DESCRIPTION - IGNITION CIRCUIT SENSE
This circuit ties the ignition switch to the Power-
train Control Module (PCM).
DESCRIPTION - POWER GROUNDS
The Powertrain Control Module (PCM) has 2 main
grounds. Both of these grounds are referred to as
power grounds. All of the high-current, noisy, electri-
cal devices are connected to these grounds as well as
all of the sensor returns. The sensor return comes
into the sensor return circuit, passes through noise
suppression, and is then connected to the power
ground.
The power ground is used to control ground cir-
cuits for the following PCM loads:
²Generator field winding
²Fuel injectors
²Ignition coil(s)
²Certain relays/solenoids
²Certain sensors
DESCRIPTION - SENSOR RETURN
The Sensor Return circuits are internal to the Pow-
ertrain Control Module (PCM).
Sensor Return provides a low±noise ground refer-
ence for all engine control system sensors. Refer to
Power Grounds for more information.
DESCRIPTION - SIGNAL GROUND
Signal ground provides a low noise ground to the
data link connector.
OPERATION - PCM - GAS ENGINES
The PCM operates the fuel system. The PCM is a
pre-programmed, triple microprocessor digital com-
puter. It regulates ignition timing, air-fuel ratio,
emission control devices, charging system, certain
transmission features, speed control, air conditioning
compressor clutch engagement and idle speed. The
PCM can adapt its programming to meet changing
operating conditions.
The PCM receives input signals from various
switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to as Powertrain Control Module
(PCM) Outputs. The sensors and switches that pro-
vide inputs to the PCM are considered Powertrain
Control Module (PCM) Inputs.
The PCM adjusts ignition timing based upon
inputs it receives from sensors that react to: engine
rpm, manifold absolute pressure, engine coolant tem-
perature, throttle position, transmission gear selec-
tion (automatic transmission), vehicle speed and the
brake switch.
The PCM adjusts idle speed based on inputs it
receives from sensors that react to: throttle position,
vehicle speed, transmission gear selection, engine
coolant temperature and from inputs it receives from
the air conditioning clutch switch and brake switch.
BR/BEELECTRONIC CONTROL MODULES 8E - 17
POWERTRAIN CONTROL MODULE (Continued)