check engine CHRYSLER VOYAGER 1996 Service Manual

INSTALLATION
(1) Position fuel tank on transmission jack. Con-
nect pressure relief/rollover valve hose. Connect fuel
filler tube vent hose and replace clamp.
(2) Raise tank into position and carefully work
filler tube into tank. A light coating of clean engine
oil on the tube end may be used to aid assembly.
(3) Feed filler vent line thru frame rail. Careful
not to cross lines.
(4) Tighten strap bolts to 54 N´m (40 ft. lbs.)
torque. Remove transmission jack.
(5) Tighten filler hose clamp to 3.3 N´m (30 in.
lbs.).
CAUTION: Ensure straps are not twisted or bent
before or after tightening strap nuts.
(6) Connect fuel pump/module electrical connector.
Place retainer in locked position.
(7) Lubricate the fuel supply line with clean 30
weight engine oil, install the quick connect fuel fit-
ting. Refer to Tube/Fitting Assembly in the Fuel
Delivery section of this Group.
(8) Attach filler line to filler tube. Pull on connec-
tor to make sure of connection.
(9) Fill fuel tank, replace cap, and connect battery
negative cable.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(10) Use the DRB scan tool ASD Fuel System Test
to pressurize the fuel system. Check for leaks.
FUEL INJECTOR RAILÐ2.4L
REMOVAL
(1) Perform fuel system pressure release procedure
before servicing or starting repairs.Refer to
Fuel System Pressure Release Procedure in this sec-
tion.
(2) Disconnect negative cable from battery.
(3) Remove air cleaner inlet hose from throttle
body.
(4) Remove throttle cable and speed control cable
(if equipped) from throttle lever.
(5) Remove throttle cables from bracket by com-
pressing retaining tabs.
(6) Remove connector from throttle position sensor.
(7) Remove connector from idle air control motor.
(8) Remove vacuum lines from intake plenum fit-
tings (Fig. 31) and (Fig. 32).(9) Remove connector from intake air temperature
sensor (Fig. 32).
(10) Remove connector from MAP sensor (Fig. 33).
(11) Remove fuel hose quick connect fitting from
the chassis tube (Fig. 34).Refer to Fuel Hoses,
Clamps and Quick Connect Fittings in this Sec-
tion.Place a shop towel under the connections to
absorb any fuel spilled from the fitting.
Fig. 31 Vacuum Fitting on Rear of Intake Manifold
Fig. 32 Electrical and Vacuum Connections
14 - 18 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

WARNING: WRAP A SHOP TOWEL AROUND
HOSES TO CATCH ANY GASOLINE SPILLAGE.
(12) Remove bolt holding bottom of intake support
bracket.
(13) Remove intake manifold screws (Fig. 35).
(14) Remove fuel rail attaching bolts.
(15) Remove fuel rail. Be careful not to damage
the injector O-rings upon removal from their ports.
INSTALLATION
(1) Ensure injector holes are clean. Replace
O-rings if damaged.
(2) Lubricate injector O-rings with a drop of clean
engine oil to ease installation.(3) Put the tip of each injector into their ports.
Push the assembly into place until the injectors are
seated in the ports.
(4) Install the fuel rail mounting bolts. Tighten
bolts to 22 N´m (200 in. lbs.) torque (Fig. 35).
(5) Install a new intake manifold gasket.
(6) Position intake manifold.
(7) Tighten retaining bolts starting at center and
progressing outward in both directions to 23 N´m
(200 in. lbs.) (Fig. 35). Repeat this procedure until all
bolts are at specified torque.
(8) Install fuel hose quick connector fitting to chas-
sis tubes.Refer to Fuel Hoses, Clamps and
Quick Connect Fittings in this Section.Push the
fitting onto the chassis tube until it clicks into place.
Pull on the fitting to ensure complete insertion.
(9) Reverse removal procedures Step 2 thru Step
12 for installation.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(10) With the ignition key in ON position, access
the DRB scan tool ASD Fuel System Test to pressur-
ize the fuel system. Check for leaks.
FUEL INJECTOR RAILÐ3.0L
WARNING: THE 3.0L MPI FUEL SYSTEM IS UNDER
A CONSTANT PRESSURE OF APPROXIMATELY 330
KPA (48 PSI). PERFORM FUEL PRESSURE
RELEASE PROCEDURE BEFORE SERVICING THE
FUEL RAIL OR FUEL INJECTORS.
REMOVAL
(1) Perform the Fuel Pressure Release Procedure.
(2) Disconnect negative cable from battery.
Fig. 33 Map SensorÐ2.4L
Fig. 34 Fuel Line Quick Disconnect
Fig. 35 Intake Manifold Attaching Points
NSFUEL SYSTEM 14 - 19
REMOVAL AND INSTALLATION (Continued)

(10) Remove air intake plenum to intake manifold
mounting fasteners (Fig. 41).
(11) Remove ignition coil.
(12) Remove air intake plenum (Fig. 42).
(13) Cover intake manifold while servicing injector
fuel rail.
(14) Disconnect fuel injector wiring harness from
engine wiring harness.
CAUTION: Do not damage the injector O-Rings
when removing the injectors and fuel rail assembly.
(15) Remove fuel rail mounting bolts. Lift fuel rail
assembly off of intake manifold.
INSTALLATION
(1) Ensure injectors are seated into the receiver
cup of fuel rail with lock ring in place.
(2) Make sure the injector holes in the manifold
are clean.
(3) To ease installation, lubricate injector O-ring
with a drop of clean engine oil.
(4) Put the tip of each injector into their ports.
Push the assembly into place until the injectors are
seated in the ports.(5) Install fuel rail attaching bolts. Tighten bolts to
13 N´m (115 in. lbs.) torque.
(6) Install fuel supply and return tube holddown
bolt and the vacuum crossover tube holddown bolt.
Tighten bolts to 10 N´m (95 in. lbs.) torque.
(7) Connect fuel injector wiring harness to engine
wiring harness.
(8) Remove covering from lower intake manifold
and clean surface.
(9) Place intake manifold gasketswith beaded
sealerupon lower manifold. Put air intake in place.
Install ignition coil. Install attaching fasteners and
tighten to 13 N´m (115 in. lbs.) torque.
(10) Connect fuel line to fuel rail.
(11) Connect vacuum harness to air intake ple-
num.
(12) Connect coolant temperature sensor electrical
connector to sensor.
(13) Connect PCV and brake booster supply hose
to intake plenum.
(14) Connect idle air control motor and Throttle
Position Sensor (TPS) electrical connectors.
(15) Connect vacuum vapor harness to throttle
body.
(16) Install throttle cable.
(17) Install air inlet resonator.
(18) Connect negative cable to battery.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(19) With the ignition key in ON position, access
the DRB scan tool ASD Fuel System Test to pressur-
ize the fuel system. Check for leaks.
FUEL INJECTOR RAILÐ3.3/3.8L
WARNING: THE 3.3/3.8L MPI FUEL SYSTEM IS
UNDER A CONSTANT PRESSURE OF APPROXI-
MATELY 330 KPA (49 PSI), 3.3L USES APPROXI-
MATELY 379 KPA (55 PSI). PERFORM FUEL
PRESSURE RELEASE PROCEDURE BEFORE SER-
VICING THE FUEL RAIL OR FUEL INJECTORS.
REMOVAL
(1) Perform fuel system pressure release proce-
dure.
(2) Disconnect negative cable from battery.
(3) Remove intake manifold cover.
(4) Remove air inlet resonator (Fig. 36).
(5) Remove throttle cable and speed control cable
(if equipped) (Fig. 43) from throttle lever and
bracket.
Fig. 41 Air Intake Plenum to Intake Manifold
Attaching Fasteners
Fig. 42 Removing Air Intake Plenum
NSFUEL SYSTEM 14 - 21
REMOVAL AND INSTALLATION (Continued)

(4) Install the fuel rail mounting bolts. Tighten
bolts to 22 N´m (200 in. lbs.) torque (Fig. 51).
(5) Install fuel tube retaining bracket screw.
Tighten screw to 4 N´m (35 in. lbs.) torque.
(6) Connect electrical connectors to camshaft posi-
tion sensor and engine coolant temperature sensor.
(7) Remove covering on lower intake manifold and
clean surface.
(8) Place intake manifold gasket on lower mani-
fold. Put upper manifold into place and install bolts
finger tight.
(9) Install the generator bracket to intake mani-
fold bolt and the cylinder head to intake manifold
strut bolts (do not tighten.)(10) Following the tightening sequence in (Fig. 50),
tighten intake manifold bolts to 28 N´m (250 in. lbs.)
torque.
(11) Tighten generator bracket to intake manifold
bolt to 54 N´m (40 ft. lbs.) torque.
(12) Tighten the cylinder head to intake manifold
strut bolts to 54 N´m (40 ft. lbs.) torque.
(13) Connect ground strap and MAP sensor electri-
cal connector.
(14) Connect vacuum harness to intake plenum.
Connect PCV system hoses.
(15) Using a new gasket, connect the EGR tube to
the intake manifold plenum. Tighten screws to 22
N´m (200 in. lbs.) torque.
(16) Connect electrical connectors to the TPS and
idle air control motor.
(17) Connect vacuum harness to throttle body.
(18) Install the direct ignition system (DIS) coils.
Tighten fasteners to 12 N´m (105 in. lbs.) torque.
(19) Install fuel hose quick connector fitting to
chassis tubes.Refer to Fuel Hoses, Clamps and
Quick Connect Fittings in this Section.Push the
fitting onto the chassis tube until it clicks into place.
Pull on the fitting to ensure complete insertion.
(20) Install throttle cable and speed control cable
(if equipped).
(21) Install air inlet resonator.
(22) Connect negative cable to battery.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(23) With the ignition key in ON position, access
the DRB scan tool ASD Fuel System Test to pressur-
ize the fuel system. Check for leaks.
FUEL INJECTORÐ2.4L
The fuel rail must be removed first. Refer to Fuel
Injector Rail Removal in this section.
REMOVAL
(1) Disconnect injector wiring connector from injec-
tor.
(2) Position fuel rail assembly so that the fuel
injectors are easily accessible (Fig. 54).
(3) Rotate injector and pull injector out of fuel rail.
The clip will stay on the injector.
(4) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. If injector is reused, a
protective cap must be installed on the injector tip to
prevent damage. Replace the injector clip if it is dam-
aged.
(5) Repeat for remaining injectors.
Fig. 52 Camshaft Position Sensor Connector
Fig. 53 Fuel Rail Removal
14 - 24 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
(1) Before installing an injector the rubber O-ring
must be lubricated with a drop of clean engine oil to
aid in installation.
(2) Install injector clip by sliding open end into the
top slot of the injector. The edge of the receiver cup
will slide into the side slots of clip.
(3) Install injector top end into fuel rail receiver
cap. Be careful not to damage O-ring during installa-
tion (Fig. 55).
(4) Repeat steps for remaining injectors.
(5) Connect fuel injector wiring.
FUEL INJECTORSÐ3.0L
WARNING: THE 3.0L MPI FUEL SYSTEM IS UNDER
A CONSTANT PRESSURE OF APPROXIMATELY 330
KPA (48 PSI). PERFORM FUEL PRESSURE
RELEASE PROCEDURE BEFORE SERVICING THE
FUEL INJECTORS.
REMOVAL
(1) Perform the Fuel Pressure Release Procedure.
(2) Disconnect negative cable from battery.
(3) The fuel rail must be removed first to service
the injectors. Refer to Fuel Injector Rail Assembly
Removal in this section.
(4) Label each injector connector with its cylinder
number. Disconnect electrical connector from injector.
(5) Position fuel rail assembly so that the fuel
injectors are easily accessible.
(6) Remove injector clip from fuel rail and injector
(Fig. 54).
(7) Pull injector straight out of fuel rail receiver
cup (Fig. 55).
(8) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. If injector is to be
reused, a protective cap must be installed on the
injector tip to prevent damage.
(9) Repeat procedure for remaining injectors.
INSTALLATION
(1) Before installing an injector, the rubber O-ring
must be lubricated with a drop of clean engine oil to
aid in installation.
(2) Being careful not to damage O-ring, install
injector nozzle end into fuel rail receiver cap.
(3) Install injector clip by sliding open end into
top slotof the injector. The edge of the receiver cup
will slide into the side slots of clip (Fig. 55)
(4) Repeat steps for remaining injectors.
(5) Install fuel rail assembly. Refer to Fuel Rail
Assembly Installation in this section.
(6) Connect electrical connectors to injectors in cor-
rect order.
(7) Connect negative battery cable.
CAUTION: When using the ASD Fuel System Test,
the ASD relay and fuel pump relay remain energized
for 7 minutes or until the test is stopped, or until
the ignition switch is turned to the Off position.
(8) With the ignition key in ON position, access
the DRB scan tool ASD Fuel System Test to pressur-
ize the fuel system. Check for leaks.
Fig. 54 Fuel Injector and RailÐTypical
Fig. 55 Servicing Fuel InjectorÐTypical
NSFUEL SYSTEM 14 - 25
REMOVAL AND INSTALLATION (Continued)

FUEL INJECTORÐ3.3/3.8L
The fuel rail must be removed first. Refer to Fuel
Injector Rail Assembly Removal in this section.
REMOVAL
(1) Disconnect injector wiring connector from injec-
tor.
(2) Position fuel rail assembly so that the fuel
injectors are easily accessible (Fig. 54).
(3) Rotate injector and pull injector out of fuel rail.
The clip will stay on the injector.
(4) Check injector O-ring for damage. If O-ring is
damaged, it must be replaced. If injector is reused, a
protective cap must be installed on the injector tip to
prevent damage. Replace the injector clip if it is dam-
aged.
(5) Repeat for remaining injectors.
INSTALLATION
(1) Before installing an injector the rubber O-ring
must be lubricated with a drop of clean engine oil to
aid in installation.
(2) Install injector clip by sliding open end into the
top slot of the injector. The edge of the receiver cup
will slide into the side slots of clip (Fig. 56).
(3) Install injector top end into fuel rail receiver
cap. Be careful not to damage O-ring during installa-
tion (Fig. 56).
(4) Repeat steps for remaining injectors.
(5) Connect fuel injector wiring.
ACCELERATOR PEDAL
CAUTION: When servicing the accelerator pedal,
throttle cable or speed control cable, do not dam-
age or kink the core wire inside the cable sheath-
ing.
REMOVAL
(1) Working from the engine compartment, remove
the throttle control shield.
(2) Hold the throttle body throttle lever in the
wide open position. Remove the throttle cable from
the throttle body cam.
(3) From inside the vehicle, hold up the pedal and
remove the cable retainer and throttle cable from the
upper end of the pedal shaft (Fig. 57) and (Fig. 58).
(4) Working from the engine compartment, remove
nuts from accelerator pedal attaching studs (Fig. 57).
Remove assembly from vehicle.
INSTALLATION
(1) Position accelerator pedal assembly on dash
panel. Install retaining nuts. Tighten retaining nuts
to 12 N´m (105 in. lbs.) torque.
Fig. 56 Servicing Fuel InjectorÐTypical
Fig. 57 Accelerator Pedal and Throttle CableÐFront
View
Fig. 58 Accelerator Pedal and Throttle CableÐRear
View
14 - 26 FUEL SYSTEMNS
REMOVAL AND INSTALLATION (Continued)

FUEL INJECTION SYSTEM
INDEX
page page
GENERAL INFORMATION
INTRODUCTION......................... 30
MODES OF OPERATION.................. 30
DESCRIPTION AND OPERATION
AIR CONDITIONING (A/C) CLUTCH RELAYÐ
PCM OUTPUT......................... 41
AIR CONDITIONING PRESSURE
TRANSDUCERÐPCM INPUT............. 33
AIR CONDITIONING SWITCH SENSEÐ
PCM INPUT........................... 33
AUTOMATIC SHUTDOWN (ASD) SENSEÐ
PCM INPUT........................... 33
AUTOMATIC SHUTDOWN RELAYÐPCM
OUTPUT............................. 42
AUTOMATIC TRANSAXLE CONTROL
MODULEÐPCM OUTPUT................ 44
BATTERY VOLTAGEÐPCM INPUT........... 33
BRAKE SWITCHÐPCM INPUT.............. 33
CAMSHAFT POSITION SENSORÐPCM INPUT . 33
CCDBUS .............................. 32
CRANKSHAFT POSITION SENSORÐPCM
INPUT............................... 35
DATA LINK CONNECTORÐPCM OUTPUT..... 44
DUTY CYCLE EVAP CANISTER PURGE
SOLENOIDÐPCM OUTPUT.............. 43
ELECTRONIC EGR TRANSDUCER
SOLENOIDÐPCM OUTPUT.............. 43
ENGINE COOLANT TEMPERATURE SENSORÐ
PCM INPUT........................... 36
FUEL INJECTORSÐPCM OUTPUT.......... 44
FUEL PUMP RELAYÐPCM OUTPUT......... 42
GENERATOR FIELDÐPCM OUTPUT......... 42
HEATED OXYGEN SENSOR (O2S SENSOR)Ð
PCM INPUT........................... 37
IDLE AIR CONTROL MOTORÐPCM OUTPUT . . 42
IGNITION COILÐPCM OUTPUT............. 45
INTAKE AIR TEMPERATURE SENSORÐPCM
INPUT (2.4L ONLY)..................... 41
KNOCK SENSORÐPCM INPUT............. 38
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT.................. 46
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐPCM INPUT.................. 39
POWERTRAIN CONTROL MODULE (PCM).... 32
PROPORTIONAL PURGE SOLENOID......... 43
SOLID STATE FAN RELAYÐPCM OUTPUT.... 46
SPEED CONTROL SOLENOIDSÐ
PCM OUTPUT......................... 46
SPEED CONTROLÐPCM INPUT............ 39STARTER RELAYÐPCM OUTPUT........... 42
SYSTEM DIAGNOSIS..................... 32
TACHOMETERÐPCM OUTPUT............. 47
THROTTLE BODY....................... 47
THROTTLE POSITION SENSOR (TPS)Ð
PCM INPUT........................... 40
TORQUE CONVERTER CLUTCH SOLENOIDÐ
PCM OUTPUT......................... 46
TRANSAXLE PARK/NEUTRAL SWITCHÐ
PCM INPUT........................... 40
VEHICLE SPEED AND DISTANCEÐ
PCM INPUT........................... 41
DIAGNOSIS AND TESTING
ASD AND FUEL PUMP RELAYS............. 59
CAMSHAFT AND CRANKSHAFT POSITION
SENSOR............................. 61
ENGINE COOLANT TEMPERATURE SENSOR . . 61
HEATED OXYGEN SENSOR............... 61
KNOCK SENSOR........................ 61
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR............................. 60
THROTTLE BODY MINIMUM AIR FLOW
CHECK PROCEDURE................... 62
THROTTLE POSITION SENSOR............ 62
VISUAL INSPECTIONÐ2.4L ENGINE......... 47
VISUAL INSPECTIONÐ3.0L ENGINE......... 52
VISUAL INSPECTIONÐ3.3/3.8L ENGINES..... 55
REMOVAL AND INSTALLATION
AIR CLEANER ELEMENT.................. 70
AUTOMATIC SHUTDOWN (ASD) RELAY...... 64
CAMSHAFT POSITION SENSOR............ 68
CRANKSHAFT POSITION SENSOR.......... 68
DOWNSTREAM OXYGEN SENSOR.......... 69
ENGINE COOLANT TEMPERATURE
SENSORÐ2.4L........................ 70
ENGINE COOLANT TEMPERATURE
SENSORÐ3.0L........................ 71
ENGINE COOLANT TEMPERATURE
SENSORÐ3.3/3.8L..................... 71
FUEL PUMP RELAY...................... 64
IDLE AIR CONTROL MOTOR............... 65
INTAKE AIR TEMPERATURE SENSORÐ2.4L . . . 72
KNOCK SENSOR........................ 70
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐ2.4/3.3/3.8L.................. 66
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐ3.0L........................ 66
POWERTRAIN CONTROL MODULE.......... 67
PROPORTIONAL PURGE SOLENOID VALVE . . . 66
NSFUEL SYSTEM 14 - 29

IGNITION SWITCH OFF MODE
When the ignition switch is turned to the OFF
position, the following occurs:
²All outputs are turned off.
²No inputs are monitored.
²The PCM shuts down.
DESCRIPTION AND OPERATION
SYSTEM DIAGNOSIS
The PCM can test many of its own input and out-
put circuits. If the PCM senses a fault in a major
system, the PCM stores a Diagnostic Trouble Code
(DTC) in memory.
For DTC information, refer to Group 25, Emission
Control Systems. See On-Board Diagnostics.
CCD BUS
Various controllers and modules exchange informa-
tion through a communications port called the CCD
Bus. The PCM transmits the malfunction indicator
(check engine) lamp On/Off signal, engine RPM and
vehicle load information on the CCD Bus.
POWERTRAIN CONTROL MODULE (PCM)
The PCM is a digital computer containing a micro-
processor (Fig. 1). The PCM receives input signals
from various switches and sensors that are referred
to as PCM Inputs. Based on these inputs, the PCM
adjusts various engine and vehicle operations
through devices that are referred to as PCM Out-
puts.PCM Inputs:
²Air Conditioning Head Pressure
²Battery Voltage
²Brake Switch
²Camshaft Position Sensor
²Crankshaft Position Sensor
²Engine Coolant Temperature Sensor
²Heated Oxygen Sensors (Upstream and Down-
stream)
²Intake Air Temperature Sensor (2.4L only)
²Knock Sensor (execpt 3.0L)
²Manifold Absolute Pressure (MAP) Sensor
²SCI Receive
²Speed Control System Controls
²Throttle Position Sensor
²Transaxle Park/Neutral Position Switch (auto-
matic transaxle)
²Transmission Control Module
²Vehicle Speed Sensor
PCM Outputs:
²Air Conditioning Clutch Relay
²Automatic Shutdown (ASD) Relay
²Data Link Connector
²Proportional Purge Solenoid
²Electric EGR Transducer
²Fuel Injectors
²Fuel Pump Relay
²Generator Field
²Idle Air Control Motor
²Ignition Coil
²Leak Detection Pump
²Malfunction Indicator (Check Engine) Lamp
²Radiator Fan Control Module
²Speed Control Solenoids
²Tachometer Output
²Torque Converter Clutch Solenoid (3 speed
transmission)
²Transmission Control Module
Based on inputs it receives, the PCM adjusts fuel
injector pulse width, idle speed, ignition spark
advance, ignition coil dwell and canister purge oper-
ation. The PCM regulates the cooling fan, air condi-
tioning and speed control systems. The PCM changes
generator charge rate by adjusting the generator
field.
The PCM adjusts injector pulse width (air/fuel
ratio) based on the following inputs:
²Battery voltage
²Engine coolant temperature
²Exhaust gas content (oxygen sensors)
²Engine speed (crankshaft position sensor)
²Manifold absolute pressure
²Throttle position
The PCM adjusts ignition timing based on the fol-
lowing inputs.
²Barometric pressure
Fig. 1 Powertrain Control Module (PCM)
14 - 32 FUEL SYSTEMNS
GENERAL INFORMATION (Continued)

Shutdown (ASD) RelayÐPCM Output in this section
for relay operation.
TORQUE CONVERTER CLUTCH SOLENOIDÐPCM
OUTPUT
Three-speed automatic transaxles use a torque con-
verter clutch solenoid. The PCM controls the engage-
ment of the torque converter clutch through the
solenoid. The torque converter clutch is engaged only
in direct drive mode. Refer to Group 21 for transaxle
information.
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT
The PCM supplies the malfunction indicator (check
engine) lamp on/off signal to the instrument panel
through the CCD Bus. The CCD Bus is a communi-
cations port. Various modules use the CCD Bus to
exchange information.
The Check Engine lamp comes on each time the
ignition key is turned ON and stays on for 3 seconds
as a bulb test.
The Malfunction Indicator Lamp (MIL) stays on
continuously, when the PCM has entered a Limp-In
mode or identified a failed emission component. Dur-
ing Limp-in Mode, the PCM attempts to keep the
system operational. The MIL signals the need for
immediate service. In limp-in mode, the PCM com-
pensates for the failure of certain components that
send incorrect signals. The PCM substitutes for the
incorrect signals with inputs from other sensors.
If the PCM detects active engine misfire severe
enough to cause catalyst damage, it flashes the MIL.
At the same time the PCM also sets a Diagnostic
Trouble Code (DTC).
For signals that can trigger the MIL (Check
Engine Lamp) refer to Group 25, On-Board
Dianostics.
SOLID STATE FAN RELAYÐPCM OUTPUT
The radiator fan runs at a variable speed depend-
ing on coolant temperature and A/C system pressure.
The radiator fan circuit contains a Solid State Fan
Relay (SSFR). Refer to the Group 8W for a circuit
schematic.
A 5 volt signal is supplied to the SSFR. The PCM
provides a pulsed ground for the SSFR. Depending
upon the amount of pulse on time, the SSFR puts out
a proportional voltage to the fan motor at the lower
speed. For instance, if the on time is 30 percent, then
the voltage to the fan motor will be 3.6 volts.
When engine coolant reaches approximately 102ÉC
(215ÉF) the PCM grounds the SSFR relay. If engine
coolant reaches 207ÉC (225ÉF) the PCM grounds the
high speed ground relay and high speed fan relay. If
the fan operates at high speed, the PCM de-energizes
the high speed relay and high speed ground relay
when coolant temperature drops to approximately
101ÉC (214ÉF). When coolant temperature drops to
101ÉC (214ÉF) the fan operates at low speed. The
PCM de-energizes the low speed relay when coolant
temperature drops to approximately 93ÉC (199ÉF).
Also, when the air conditioning pressure switch
closes, the fan operates at high speed. The air condi-
tioning switch closes at 285 psi610 psi. When air
conditioning pressure drops approximately 40 psi, the
pressure switch opens and the fan operates at low
speed.
The SSFR relay is located on the left front inner
frame just behind the radiator (Fig. 42).
SPEED CONTROL SOLENOIDSÐPCM OUTPUT
The speed control vacuum and vent solenoids are
operated by the PCM. When the PCM supplies a
ground to the vacuum and vent solenoids, the speed
control system opens the throttle plate. When the
PCM removes the ground from the vacuum and vent
solenoids, the throttle blade closes. The PCM bal-
Fig. 41 Ignition Coil Ð3.3/3.8L
Fig. 42 Fan Control Module
14 - 46 FUEL SYSTEMNS
DESCRIPTION AND OPERATION (Continued)

ances the two solenoids to maintain the set speed.
Refer to Group 8H for speed control information.
TACHOMETERÐPCM OUTPUT
The PCM supplies engine RPM to the instrument
panel tachometer through the CCD Bus. The CCD
Bus is a communications port. Various modules use
the CCD Bus to exchange information. Refer to
Group 8E for more information.
THROTTLE BODY
On all engine assemblies (2.4, 3.0, and 3.3/3.8L)
the throttle body's are located on the left side of the
intake manifold plenum. The throttle body houses
the throttle position sensor and the idle air control
motor. Air flow through the throttle body is con-
trolled by a cable operated throttle blade located in
the base of the throttle body (Fig. 43) or (Fig. 44) or
(Fig. 45).
DIAGNOSIS AND TESTING
VISUAL INSPECTIONÐ2.4L ENGINE
A visual inspection for loose, disconnected, or mis-
routed wires and hoses should be made before
attempting to diagnose or service the fuel injection
system. A visual check helps save unnecessary test
and diagnostic time. A thorough visual inspection will
include the following checks:
(1) Check ignition cable routing from the coil pack
to the spark plugs. Verify the cable are routed in the
correct order and are fully seated to the coil and
spark plug.
(2) Check direct ignition system (DIS) coil electri-
cal connection for damage and a complete connection
to the coil pack (Fig. 46).
Fig. 43 Throttle BodyÐ2.4L
Fig. 44 Throttle BodyÐ3.0L
NSFUEL SYSTEM 14 - 47
DESCRIPTION AND OPERATION (Continued)