fuel pump CHRYSLER CARAVAN 2005 Workshop Manual

TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 297) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
Fig. 297 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - CONVERTER CLUTCH DISC
6 - DRIVE PLATE
21 - 124 40TE AUTOMATIC TRANSAXLERS

TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 321) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
Fig. 321 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - CONVERTER CLUTCH DISC
6 - DRIVE PLATE
RS41TE AUTOMATIC TRANSAXLE21 - 275

CABIN HEATER
TABLE OF CONTENTS
page page
CABIN HEATER
DESCRIPTION........................113
OPERATION
MANUAL TEMPERATURE CONTROL
SYSTEM...........................113
AUTOMATIC TEMPERATURE CONTROL
SYSTEM...........................114
WARNING............................114
DIAGNOSIS AND TESTING
SUPPLEMENTAL CABIN HEATER........114
AIR INTAKE PIPE
REMOVAL............................115
INSTALLATION........................115
EXHAUST TUBE
REMOVAL............................116
INSTALLATION........................116
FUEL DOSING PUMP
DESCRIPTION........................117
OPERATION..........................117REMOVAL............................117
INSTALLATION........................117
FUEL LINE
STANDARD PROCEDURE
CLEANING..........................118
REMOVAL............................118
INSTALLATION........................118
HEATER HOSES
REMOVAL............................119
INSTALLATION........................119
HEATER PIPES
REMOVAL............................119
INSTALLATION........................120
HEATER UNIT
REMOVAL............................121
INSTALLATION........................122
HEATER WIRING
REMOVAL............................122
INSTALLATION........................122
CABIN HEATER
DESCRIPTION
Vehicles equipped with the diesel engine are also
equipped with a supplemental cabin heater. This
cabin heater is mounted under the vehicle and oper-
ates similar to an oil fired furnace. The heater burns
small amounts of fuel to provide additional heat to
the coolant. Coolant is routed from the engine, to the
supplemental cabin heater and then to the front
heater core. This provides additional heat to the pas-
senger compartment. The supplemental cabin heater
system is interfaced to the vehicles on-board com-
puter systems and DRBIIItdiagnostics.
The supplemental cabin heater has an electronic
control module that monitors the heat output of the
heater. The cabin heater operates at full load (5 kW),
half load or idle mode (no additional heat) depending
on engine coolant temperature.
When ambient temperatures are lower than 15É C
(60É F), the supplemental cabin heater automatically
operates once each ignition cycle for five minutes.
This assures a good fuel supply is always present for
the supplemental cabin heater.
OPERATION
MANUAL TEMPERATURE CONTROL SYSTEM
The supplemental cabin heater is activated via the
temperature slide control or knob on the A/C-heater
control when equipped with the manual temperature
control (MTC) system. If the slide control or knob is
moved to or above the upper set point the cabin
heater is activated. The cabin heater can operate in a
full or partial load range as well as an idle mode all
dependent on the engine coolant temperature. The
cabin heater will also turn off if the A/C-heater tem-
perature control is lowered to less than the lower set
point. The cabin heater can take up to three minutes
to completely shut down when either the heater tem-
perature is set below the lower set point or the vehi-
cle ignition is shut down.
NOTE: Do not apply a strong vacuum source such
as a garage ventilation system directly on the sup-
plemental cabin heater exhaust line. Too strong of a
vacuum can prevent the supplemental cabin heater
from starting. If required, place the vacuum source
at least 75 mm (3 in.) away from the exhaust line.
RSCABIN HEATER24 - 113

Symptom Possible Causes
Loss of coolant (Leakage) or heater
develops smoke during combustion
operation and exhaust has an
extremely sweet smell.Inspect coolant hoses for leakage, kinks or loose hose connection.
Inspect the exhaust tube assembly for continuous flow, if OK there is an
internal heater leak and cabin heater should be inspected and
components should be replaced as required.
Loss of fuel (dripping). Check cabin heater system integration in vehicles fuel system. Check
fuel line connection for leakage. If OK there is an internal leak and
cabin heater should be inspected and replaced as required.
AIR INTAKE PIPE
REMOVAL
NOTE: The air intake tube for the supplemental
cabin heater is part of an assembly that includes
the heater cooling intake and return pipes. If the
cabin heater air intake tube requires removal or
replacement the entire cabin heater assembly will
require removal or replacement.
(1) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(2) Remove clamps from the cabin heater tubes at
the lower heater port and the lower EGR connector
which are located under the hood.
(3) Remove the retaining clamp at the cabin
heater air intake muffler connection (Refer to 24 -
HEATING & AIR CONDITIONING/CABIN HEAT-
ER/INLET MUFFLER - REMOVAL).
(4) Remove the clamp at the flexible tube to steel
tube connection (Fig. 1).(5) Remove the two retaining screws and remove
pipe assembly (Fig. 2).
INSTALLATION
(1) Install the air intake pipe assembly and install
the two retaining screws. Tighten the screws to 7
N´m (62 in. lbs.).
(2) Attach the steel tube to the flexible tube and
position and then tighten the retaining clamp
securely.
(3) Install the flexible tube to the cabin heater air
intake muffler and install and tighten the retaining
clamp securely.
(4) Install the cabin heater tubes to the lower
heater connection and the lower EGR cooler connec-
tion and tighten the retaining clamps.
(5) Lower the vehicle.
Fig. 1 Flexible Air Intake Line
1 - CABIN HEATER AND SPLASH SHIELD
2 - DOSING PUMP
3 - DOSING PUMP FUEL LINE
4 - FLEXIBLE AIR INTAKE LINE
5 - CLAMP
6 - STEEL INTAKE PIPE
Fig. 2 Cabin Heater Air Intake And Heater Pipe
Assembly
1 - INTAKE TUBE AIR INTAKE
2 - INTAKE PIPE
3 - RETAINING SCREWS
4 - INTAKE HEATER LINE
5 - RETURN HEATER LINE
RSCABIN HEATER24 - 115
CABIN HEATER (Continued)

FUEL DOSING PUMP
DESCRIPTION
The dosing pump is a combined delivery, dosing
and shut-off system for the fuel supply to the supple-
mental cabin heater from the vehicle fuel tank.
OPERATION
The dosing pump is an electrically operated pump
that receives its operation instructions from the sup-
plemental cabin heater control module. The pump
supplies diesel fuel from the vehicle fuel tank to the
cabin heater.
REMOVAL
NOTE: The dosing pump is serviceable without
removing the supplemental cabin heater from the
vehicle.
(1) Disconnect and isolate the negative battery
cable.
CAUTION: Make sure that the hoist is properly posi-
tioned under the vehicle to prevent damage to the
flexible section of the cabin heater exhaust tube.
(2) Raise and support the vehicle.
(3) Disconnect the wiring harness connector to the
dosing pump by depressing the integral spring and
pulling the connector away from the pump.
NOTE: Utilize an approved fuel storage container to
catch any residual fuel that may drain from the
heater fuel hose or the dosing pump.
(4) Remove the clamp that secures the heater fuel
hose to the dosing pump (Fig. 4).
(5) Disconnect the heater fuel hose from the dosing
pump.
NOTE: Position and retain the heater fuel line to
prevent fuel leakage from the cabin heater unit
while servicing the dosing pump.
(6) Disconnect the fuel line between the dosing
pump and the cabin heater unit.
NOTE: Have an approved fuel storage container
ready to catch any residual fuel that may drain from
the fuel line or the cabin heater unit.(7) Remove the dosing pump from the rubber iso-
lator and the vehicle.
INSTALLATION
(1) Position the dosing pump to the vehicle and
onto the rubber isolator.
(2) Connect the fuel line between the dosing pump
and the cabin heater unit.
NOTE: The connectors should point towards the
cabin heater fuel line.
(3) Connect the heater fuel hose to the dosing
pump.
(4) Install the clamp that secures the heater fuel
hose to the dosing pump. Tighten the clamp securely.
(5) Connect the wire harness connector to the dos-
ing pump by depressing the integral spring and
pushing the connector toward the pump. Verify con-
nector installation.
(6) Lower the vehicle
(7) Reconnect the negative battery cable.
(8) Verify function of the supplemental cabin
heater.
Fig. 4 Dosing Pump Fuel Line
1 - HEATER FUEL LINE
2 - HEATER FUEL HOSE
3 - HEATER AIR INTAKE PIPE
4 - RETAINING CLAMP (2)
5 - DOSING PUMP
RSCABIN HEATER24 - 117

FUEL LINE
STANDARD PROCEDURE
CLEANING
(1) Remove the cabin heater fuel line (Refer to 24 -
HEATING & AIR CONDITIONING/CABIN HEAT-
ER/FUEL LINE - REMOVAL).
(2) With the cabin heater fuel line removed from
the vehicle, place a shop cloth on the fuel tank end of
the fuel line to catch any residue, then apply a small
amount of air pressure to the other end of the fuel
line.
(3) Check to see if air pressure is coming from the
tank end of the line. If pressure is flowing unre-
stricted the line is clean.
(4) If the fuel line shows any signs of being
restricted after air pressure is applied, the fuel line
should be replaced.
(5) Install the cabin heater fuel line (Refer to 24 -
HEATING & AIR CONDITIONING/CABIN HEAT-
ER/FUEL LINE - INSTALLATION).
(6) Verify function of the cabin heater.
REMOVAL
CAUTION: Make sure that the hoist is properly posi-
tioned under the vehicle to prevent damage to the
flexible section of the cabin heater exhaust tube.
(1) Raise and support the vehicle.
NOTE: Utilize an approved fuel storage container to
catch any residual fuel that may drain from the
heater fuel hose or the dosing pump.
(2) Remove the two clamps that secure the heater
fuel hose to the dosing pump and the heater fuel line
(Fig. 5).
(3) Disconnect the heater fuel hose from the dosing
pump and the heater fuel line.
(4) Remove the clamp that secures the heater fuel
line to the fuel tank.
(5) Disconnect the heater fuel line from the fuel
tank.
(6) Disconnect the fuel line from the body retain-
ing clips and remove the fuel line from vehicle.
INSTALLATION
WARNING: DO NOT OPERATE THE DIESEL SUP-
PLEMENTAL CABIN HEATER IN AN ENCLOSED
AREA SUCH AS A GARAGE THAT DOES NOT HAVE
EXHAUST VENTILATION FACILITIES. ALWAYS VENT
THE CABIN HEATER EXHAUST WHEN OPERATING
THE CABIN HEATER. ALLOW THE DIESEL SUPPLE-
MENTAL CABIN HEATER TO COOL BEFORE PER-
FORMING ANY SERVICE PROCEDURES TO THE
CABIN HEATER. VERIFY THAT ALL DIESEL SUP-
PLEMENTAL CABIN HEATER FUEL LINES ARE
SECURELY FASTENED TO THEIR RESPECTIVE
COMPONENTS BEFORE PERFORMING ANY SER-
VICE PROCEDURES TO THE CABIN HEATER. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS MAY
RESULT IN PERSONAL INJURY OR DEATH.
(1) Position the cabin heater fuel line to the vehi-
cle and connect the body retaining clips.
(2) Connect the heater fuel line to the fuel tank.
(3) Install the clamp that secure the heater fuel
line to the fuel tank. Tighten the clamp securely.
(4) Connect the heater fuel hose to the dosing
pump and the heater fuel line.
(5) Install the clamps that secure the heater fuel
hose to the dosing pump and the heater fuel line.
Tighten the clamps securely.
(6) Lower the vehicle.
Fig. 5 Dosing Pump Fuel Line
1 - HEATER FUEL LINE
2 - HEATER FUEL HOSE
3 - HEATER AIR INTAKE PIPE
4 - RETAINING CLAMP (2)
5 - DOSING PUMP
24 - 118 CABIN HEATERRS

NOTE: Verify that there is more than 1/8 of a tank of
fuel in the vehicle's fuel tank before performing this
procedure. Add fuel, if necessary.
NOTE: Failure to prime the dosing pump after drain-
ing the supplemental cabin fuel line will prevent
cabin heater activation during the first attempt to
start the cabin heater. This will also set a diagnostic
trouble code (DTC) in the cabin heater control's
memory. Do not perform the Dosing Pump Priming
procedure if an attempt was made to start the cabin
heater without priming the dosing pump first. This
will put excess fuel in the cabin heater and cause
smoke to emit from the cabin heater exhaust pipe
when cabin heater activation occurs.
(7) Connect the DRBIIItscan tool to the diagnos-
tic link connector.
(8) Turn the ignition to the ON position.
NOTE: Do not activate the dosing pump prime more
than one time. This will put excess fuel in the sup-
plemental cabin heater and cause smoke to emit
from the cabin heater exhaust pipe when cabin
heater activation occurs.
NOTE: A clicking noise heard coming from the dos-
ing pump indicates that the pump is operational.
(9) With the DRBIIItscan tool in Cabin Heater,
select System Tests and Dosing Pump Prime. Allow
the dosing pump to run for the full 45 second cycle
time. When the 45 second cycle is complete, press
Page Back on the DRBIIItscan tool key pad to exit
the Dosing Pump Prime. The Dosing Pump Priming
procedure is now complete.
HEATER HOSES
REMOVAL
(1) Raise and support the vehicle. Take note of the
location of the flexible section of the cabin heater
exhaust tube.
(2) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
NOTE: Complete removal of the supplemental cabin
heater from vehicle is not required, lowering the
cabin heater allows easier access to coolant line
clamps.(3) Lower the supplemental cabin heater from the
vehicle (Refer to 24 - HEATING & AIR CONDITION-
ING/CABIN HEATER/HEATER UNIT - REMOVAL).
(4) Remove the clamps from both flexible coolant
line ends.
NOTE: It is recommended that both flexible cabin
heater coolant lines be replaced if either cabin
heater coolant line is damaged.
(5) Remove both coolant lines from vehicle.
INSTALLATION
(1) Install both flexible coolant lines to the supple-
mental cabin heater and install the clamps.
(2) Install the flexible coolant lines to the coolant
pipes and install the clamps.
(3) Install the supplemental cabin heater into the
vehicle (Refer to 24 - HEATING & AIR CONDITION-
ING/CABIN HEATER/HEATER UNIT - INSTALLA-
TION).
(4) Lower the vehicle.
(5) Fill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(6) Verify operation of the supplemental cabin
heater.
HEATER PIPES
REMOVAL
WARNING: ALLOW THE ENGINE COOLING SYSTEM
TO COOL COMPLETELY BEFORE REMOVING RADI-
ATOR CAP OR DRAINING THE ENGINE COOLING
SYSTEM. PERSONAL INJURY MAY RESULT IF THE
ENGINE COOLING SYSTEM IS OPENED WHILE
ENGINE COOLANT IS HOT AND UNDER PRES-
SURE.
NOTE: Steel heater lines from engine compartment
to the supplemental cabin heater are part of an
assembly that includes the air intake pipe. If the
cabin heater lines or air intake pipe require removal
or replacement the entire cabin heater assembly
will require removal or replacement.
(1) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(2) Remove clamps from both the EGR cooler and
the lower heater port. Separate hoses from the mat-
ing plumbing port (Fig. 6).
RSCABIN HEATER24 - 119
FUEL LINE (Continued)

(7) Connect the heater lines to the heater hoses at
the heater core and EGR port. Position spring clamps
onto the hoses.
(8) Fill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
HEATER UNIT
REMOVAL
WARNING: DO NOT OPERATE THE DIESEL SUP-
PLEMENTAL CABIN HEATER IN AN ENCLOSED
AREA SUCH AS A GARAGE THAT DOES NOT HAVE
EXHAUST VENTILATION FACILITIES. ALWAYS VENT
THE CABIN HEATER EXHAUST WHEN OPERATING
THE CABIN HEATER. ALLOW THE DIESEL SUPPLE-
MENTAL CABIN HEATER TO COOL BEFORE PER-
FORMING ANY SERVICE PROCEDURES TO THE
CABIN HEATER. VERIFY THAT ALL DIESEL SUP-
PLEMENTAL CABIN HEATER FUEL LINES ARE
SECURELY FASTENED TO THEIR RESPECTIVE
COMPONENTS BEFORE PERFORMING ANY SER-
VICE PROCEDURES TO THE CABIN HEATER. FAIL-
URE TO FOLLOW THESE INSTRUCTION MAY
RESULT IN PERSONAL INJURY OR DEATH.(1) Raise and support the vehicle. Take note of the
location of the flexible section of the cabin heater
exhaust tube.
(2) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(3) Carefully open one hose to the underbody tube
assembly and drain the remaining coolant. A salvage
hose is a good idea to control the residual coolant, as
flow will occur from both the cabin heater and the
hose and tube assemblies.
(4) Remove the second hose from the underbody
hose and tube assembly.
(5) Loosen the hose and tube assembly from the
toe-board crossmember at two locations.
(6) Disconnect the electrical connector from the
body harness near the toe-board crossmember and
rail.
(7) Remove the wiring harness from the toe-board
crossmember (Refer to 24 - HEATING & AIR CON-
DITIONING/CABIN HEATER/HEATER UNIT -
REMOVAL).
(8) Open the fuel filler cap. Disconnect the rubber
fuel hose between the body tube assembly and the
fuel pump nipple at the body tube joint. A minimal
amount of fuel may flow from the open port.
NOTE: Utilize an approved fuel storage container to
catch any residual fuel.
(9) Loosen the two fasteners at the rail. Take care
to notice that the exhaust tube bracket tab is on top
of the heater bracket and that there are two spacer
washers installed between the rubber grommets.
(10) Remove the flexible section of the cabin
heater exhaust tube from the exhaust tube by loos-
ening the clamp. Remove the hose from the exhaust
tube. Removal of the rail tube assembly may aid in
this service operation (Refer to 24 - HEATING & AIR
CONDITIONING/CABIN HEATER/EXHAUST TUBE
- REMOVAL).
(11) Remove seat hex nut at the heater mounting
flange to crossmember.
(12) Loosen the remaining fasteners which mount
the exhaust tube assembly to the vehicle.
(a) Install a suitable support device under the
cabin heater and secure the cabin heater to the
support.
(13) Loosen the remaining three fasteners to the
crossmembers.
(14) Remove the loosened fasteners that support
the cabin heater while supporting the weight of the
heater.
(15) Swing the cabin heater mounting bracket
from between the exhaust bracket and rail mounting
location. Drain any residual coolant from the cabin
heater.
Fig. 7 Cabin Heater Air Intake And Heater Pipe
Assembly
1 - INTAKE TUBE AIR INTAKE
2 - INTAKE PIPE
3 - RETAINING SCREWS
4 - INTAKE HEATER LINE
5 - RETURN HEATER LINE
RSCABIN HEATER24 - 121
HEATER PIPES (Continued)

(16) Remove the cabin heater from the vehicle.
INSTALLATION
(1) Install the cabin heater mounting bracket
between the exhaust bracket and the rail mounting
location.
(2) Support the cabin heater and install the fasten-
ers that secure the cabin heater to the mounting
bracket.
(3) Install the three fasteners to the crossmem-
bers. Tighten the M6 fasteners to 7 N´m (62 in. lbs.).
(4) Position the two spacer washers between the
body and the rubber grommets for the two mounting
points on the rail.
(5) Tighten the remaining M6 fasteners to 7 N´m
(62 in. lbs.) and the M8 fasteners to 23 N´m (17 ft.
lbs.) which mount the exhaust tube assembly to the
vehicle.
(6) Install the seat hex nut at the heater mounting
flange to the crossmembers. Tighten the nut to 60
N´m (44 ft. lbs.)
(7) Install the flexible section of the cabin heater
exhaust tube to the exhaust tube. Tighten the M6
bolt of the clamp securley. Install the hose to the
exhaust tube.
(8) Tighten the two M8 fasteners at the rail to 23
N´m (17 ft. lbs.). Taking care so that the exhaust
tube bracket tab is on the top of the heater bracket.
(9) Install the wiring harness (Refer to 24 - HEAT-
ING & AIR CONDITIONING/CABIN HEATER/
HEATER UNIT - INSTALLATION).
(10) Tighten the hose and tube assembly to the
toe-board crossmember at two locations.
(11) Install the second hose to the underbody hose
and tube assembly.
(12) Connect the rubber fuel hose between the
body tube assembly and the fuel pump nipple at the
body tube joint. Close the fuel fill cap.
(13) Remove the cabin heater support device from
under the vehicle.
(14) Lower the vehicle.(15) Fill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Verify function of the cabin heater.
HEATER WIRING
REMOVAL
(1) Elevate vehicle on a lift taking note of the
exhaust tube flexible section.
(2) Unplug connector from vehicle wiring harness
to cabin heater harness.
(3) Unplug connector from cabin heater harness to
dosing pump connector.
(4) Unplug two connectors from cabin heater har-
ness to cabin heater controller connectors.
(5) Remove two wiring harness connectors from
underbody.
(6) Remove two wiring harness connectors from
cabin heater shield.
(7) Carefully route the cabin heater harness to the
left side between the cabin heater unit and the cabin
heater shield.
INSTALLATION
(1) Carefully route the cabin heater harness from
the left side of the cabin heater between the cabin
heater unit and the cabin heater shield.
(2) Install the two wiring harness retaining con-
nectors to the cabin heater shield.
(3) Route the wiring harness along the underside
of the vehicle and install the two wiring harness
retaining connectors.
(4) Plug the two connectors from the cabin heater
harness to the cabin heater controller.
(5) Plug the connector to the cabin heater harness
to the dosing pump connector.
(6) Plug the connector from the vehicle wiring har-
ness to the cabin heater harness.
(7) Lower the vehicle.
(8) Verify function of the cabin heater.
24 - 122 CABIN HEATERRS
HEATER UNIT (Continued)

The major non-monitored circuits are listed below
along with examples of failures modes that do not
directly cause the PCM to set a DTC, but for a sys-
tem that is monitored.
FUEL PRESSURE
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor, fuel system, or mis-
fire diagnostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables. The misfire will however,
increase the oxygen content in the exhaust, deceiving
the PCM in to thinking the fuel system is too lean.
Also see misfire detection. There are DTC's that can
detect misfire and Ionization shorts in the secondary
ignition circuit, refer to the Powertrain Diagnostic
manual for more information
CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine
cylinder compression. Low compression lowers O2
content in the exhaust. Leading to fuel system, oxy-
gen sensor, or misfire detection fault.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or
leaking exhaust system. It may set a EGR (if
equipped) or Fuel system or O2S fault.
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The PCM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injector
is installed. However, these could result in a rich or
lean condition causing the PCM to store a diagnostic
trouble code for either misfire, an oxygen sensor, or
the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen
content when the system is in closed loop, it cannot
determine excessive oil consumption.
THROTTLE BODY AIR FLOW
The PCM cannot detect a clogged or restricted air
cleaner inlet or filter element.
VACUUM ASSIST
The PCM cannot detect leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices. However, these could cause the PCMto store a MAP sensor diagnostic trouble code and
cause a high idle condition.
PCM SYSTEM GROUND
The PCM cannot determine a poor system ground.
However, one or more diagnostic trouble codes may
be generated as a result of this condition. The mod-
ule should be mounted to the body at all times,
including when diagnostics are performed.
PCM CONNECTOR ENGAGEMENT
The PCM may not be able to determine spread or
damaged connector pins. However, it might store
diagnostic trouble codes as a result of spread connec-
tor pins.
DESCRIPTION - MONITORED SYSTEMS
There are new electronic circuit monitors that
check fuel, emission, engine and ignition perfor-
mance. These monitors use information from various
sensor circuits to indicate the overall operation of the
fuel, engine, ignition and emission systems and thus
the emissions performance of the vehicle.
The fuel, engine, ignition and emission systems
monitors do not indicate a specific component prob-
lem. They do indicate that there is an implied prob-
lem within one of the systems and that a specific
problem must be diagnosed.
If any of these monitors detect a problem affecting
vehicle emissions, the Malfunction Indicator (Check
Engine) Lamp will be illuminated. These monitors
generate Diagnostic Trouble Codes that can be dis-
played with the a scan tool.
The following is a list of the system monitors:
²EGR Monitor (if equipped)
²Misfire Monitor
²Fuel System Monitor
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
²Evaporative System Leak Detection Monitor (if
equipped)
Following is a description of each system monitor,
and its DTC.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
OXYGEN SENSOR (O2S) MONITOR
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperatures of 300É to 350ÉC (572É to 662ÉF),
the sensor generates a voltage that is inversely pro-
portional to the amount of oxygen in the exhaust.
25 - 6 EMISSIONS CONTROLRS
EMISSIONS CONTROL (Continued)