electr CHRYSLER VOYAGER 2002 Service Manual
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Page 2318 of 2399
ward far enough to disengage the engine compart-
ment ends of the tubes from the dash panel seal.
(14) Remove the heater core tubes and sealing
plate as a unit from beneath the instrument panel.
(15) Use absorbent toweling to clean up any
engine coolant spills from the preceding operation.
REMOVAL - HEATER CORE
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING FRONT - WARNING - HEATER PLUMB-
ING).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Drain the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM DRAIN).
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the silencer boot fasteners located
around the base of the lower steering shaft from the
dash panel so that it may be pushed aside.
(4) Remove the brake lamp switch from its mount-
ing bracket. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
REMOVAL).
(5) Disconnect the power brake booster input rod
(push rod) from the pin on the brake pedal arm.
(Refer to 5 - BRAKES - ABS/HYDRAULIC/ME-
CHANICAL/POWER BRAKE BOOSTER - REMOV-
AL).
(6) Remove the three screws that secure the heater
core shield to the left end of the HVAC distribution
housing (Fig. 17).
(7) Pull the heater core shield rearward far enough
to disengage the two location tabs that position the
front of the shield to the receptacles in the two lower
finger formations of the evaporator housing near the
dash panel.(8) Remove the heater core shield from the distri-
bution housing.
(9) Take the proper precautions to protect the car-
peting below the heater core from spilled engine cool-
ant and have absorbent toweling readily available to
mop up any spills.
(10) Remove the screw that secures the heater core
tube sealing plate to the heater core supply and
return ports (Fig. 18).
Fig. 17 Heater Core Shield
1 - HEATER/ AIR CONDITIONER HOUSING
2 - HEATER CORE SHIELD
3 - DISTRIBUTION HOUSING
4 - SCREWS (3)
5 - LOCATION TABS (2)
Fig. 18 Heater Core
1 - SEALING PLATE
2 - SCREW
3 - SCREWS (2)
4 - HEATER CORE
5 - HEATER CORE TUBES
RSPLUMBING - FRONT24-75
HEATER CORE (Continued)
ProCarManuals.com
Page 2320 of 2399
(6) Install and tighten the screw that secures the
heater core tube sealing plate to the heater core sup-
ply and return ports. Tighten the screw to 3 N´m (27
in. lbs.).
(7) Position the heater core shield onto the distri-
bution housing. Be certain that the two location tabs
on the front of the shield are engaged in the recepta-
cles in the two lower finger formations of the evapo-
rator housing near the dash panel.
(8) Install and tighten the three screws that secure
the heater core shield to the left end of the HVAC
distribution housing. Tighten the screws to 2 N´m (17
in. lbs.).
(9) Reinstall the silencer under the driver side end
of the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/INSTRUMENT PANEL
SILENCER - INSTALLATION).
(10) Reconnect the heater hoses to the heater hose
tubes. (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - FRONT/HEATER HOSE -
INSTALLATION).
(11) Reconnect the battery negative cable.
(12) Refill the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
INSTALLATION - HEATER CORE
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING FRONT - WARNING - HEATER PLUMB-
ING).
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.(1) While pushing the brake pedal downward and
pulling the accelerator pedal upward far enough for
clearance, slide the heater core into the distribution
housing.
(2) Install and tighten the two screws that secure
the heater core mounting plate to the distribution
housing. Tighten the screws to 2 N´m (17 in. lbs.).
(3) Remove the plugs or tape from the heater core
tube fittings and both heater core ports.
(4) Position both heater core tubes and the sealing
plate simultaneously to the heater core supply and
return ports.
(5) The heater core tubes each have a slot that
must be indexed to a location tab within each of the
heater core ports. Adjust the position of the tubes as
required so that the sealing plate fits flush against
the heater core supply and return ports, which indi-
cates that the tubes are properly indexed.
(6) Install and tighten the screw that secures the
heater core tube sealing plate to the heater core sup-
ply and return ports. Tighten the screw to 3 N´m (27
in. lbs.).
(7) Position the heater core shield onto the distri-
bution housing. Be certain that the two location tabs
on the front of the shield are engaged in the recepta-
cles in the two lower finger formations of the evapo-
rator housing near the dash panel.
(8) Install and tighten the three screws that secure
the heater core shield to the left end of the HVAC
distribution housing. Tighten the screws to 2 N´m (17
in. lbs.).
(9) Reconnect the power brake booster input rod
(push rod) to the pin on the brake pedal arm(Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/POWER
BRAKE BOOSTER - INSTALLATION).
(10) Reinstall the brake lamp switch into its
mounting bracket(Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
INSTALLATION).
(11) Reinstall the silencer boot around the base of
the lower steering shaft on the dash panel.
(12) Reconnect the battery negative cable.
(13) Refill the engine cooling system. (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
(14) Operate system for two thermostat cycles to
assure elimination of air in the system.
RSPLUMBING - FRONT24-77
HEATER CORE (Continued)
ProCarManuals.com
Page 2332 of 2399
location of a possible refrigerant leak, the exact leak
location should be confirmed with an electronic leak
detector prior to component repair or replacement.
An electronic leak detector designed for R-134a
refrigerant is recommended for locating and confirm-
ing refrigerant system leaks. See the operating
instructions supplied by the equipment manufacturer
for proper care and use of this equipment.
To detect a leak in the refrigerant system, perform
one of the following procedures as indicated by the
results of the refrigerant system charge level test.
SYSTEM EMPTY
(1) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(2) Connect and dispense 0.283 kilograms (0.625
pounds or 10 ounces) of R-134a refrigerant into the
evacuated refrigerant system. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - FRONT/
REFRIGERANT - STANDARD PROCEDURE -
REFRIGERANT SYSTEM CHARGE).
(3) Proceed to the SYSTEM LOW procedures.
SYSTEM LOW
(1) Position the vehicle in a wind-free work area.
This will aid in detecting small leaks.
(2) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run at idle under the following condi-
tions for five minutes, then turning the engine off.
(a) Front windows are open.
(b) Rear air conditioner Off (if equipped).
(c) Transaxle in Park.
(d) Front heater-A/C controls set to outside air,
panel mode, blower high, and compressor engaged.
(3) Wait five to seven minutes and, with the
engine not running, use a electronic R-134a leak
detector and search for leaks. Because R-134a refrig-
erant is heavier than air, the leak detector probe
should be moved slowly along the bottom side of all
refrigerant lines, connector fittings and components.
(4) To inspect an evaporator for leaks, insert the
electronic leak detector probe into a floor outlet or
the recirculation air intake.
DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM CHARGE LEVEL 2.5L DIESEL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
NOTE: The proper amount of R-134a refrigerant for
the refrigerant system in this model is:
²Single or Dual Zone (Front Unit Only - 2.5L Die-
sel) ± 0.91 kilograms (2.00 pounds or 32 ounces)
²Single or Dual Zone (Front Unit Only) - 0.96
kilograms (2.13 pounds or 34 ounces)
²Three Zone (Front and Rear Units) - 1.31 kilo-
grams (2.88 pounds or 46 ounces)
The procedure that follows should be used to deter-
mine whether the refrigerant system contains the
proper refrigerant charge. Symptoms of an improper
refrigerant charge (low) include: poor air conditioner
performance, fog emitted from the air conditioner
outlets, a hissing sound from the expansion valve/
evaporator area. There are two different methods
with which the refrigerant charge level may be
tested:
²Using a DRBIIItscan tool, a thermocouple and
the Charge Determination Chart (Fig. 34). Refer to
the appropriate diagnostic information.
²Using a manifold gauge set, a thermocouple and
the Charge Determination Chart (Fig. 34).
A temperature probe is required to measure liquid
line temperature. The clamp-on, Type K thermocou-
ple temperature probe used in this procedure is
available through the DaimlerChrysler Professional
Service Equipment (PSE) program. This probe (PSE
#66-324-0014 or #80PK-1A) is compatible with tem-
perature-measuring instruments that accept Type K
thermocouples, and have a miniature connector
input. Other temperature probes are available
through aftermarket sources; however, all references
in this procedure will reflect the use of the probe
made available through the PSE program.
In order to use the temperature probe, a digital
thermometer will also be required. If a digital ther-
mometer is not available, an adapter is available
through the PSE program that will convert any stan-
dard digital multimeter into a digital thermometer.
This adapter is designed to accept any standard Type
K thermocouple. If a digital multimeter is not avail-
able, this tool is also available through the PSE pro-
gram.
NOTE: When connecting the service equipment
couplings to the refrigerant system service ports,
be certain that the valve of each coupling is fully
closed. This will reduce the amount of effort
required to make the connection.
(1) Remove the caps from the refrigerant system
service ports and attach a manifold gauge set or a
R-134a refrigerant recovery/recycling/charging sta-
RSPLUMBING - FRONT24-89
REFRIGERANT (Continued)
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Page 2354 of 2399
FUEL DOSING PUMP
DESCRIPTION
The dosing pump is a combined delivery, dosing
and shut-off system for the fuel supply to the heater
from the vehicles fuel tank.
OPERATION
The dosing pump is an electrically operated pump
that receives its operation instructions from the sup-
plemental heater electronic control module. The
pump supplies diesel fuel from the fuel tank to the
heater unit.
REMOVAL
The dosing pump is serviceable without removing
the component from the vehicle.
(1) Disconnect the rubber hose at the fuel line to
heater fuel pump. Leave the rubber hose on the fuel
line.(Refer to 24 - HEATING & AIR CONDITION-
ING/CABIN HEATER/FUEL LINE - REMOVAL)
(Fig. 2).
(2) Disconnect the fuel line between the dosing
pump and the heater unit.NOTE: Position and retain heater fuel line to pre-
vent fuel leakage while servicing dosing pump.
NOTE: Utilize an approved fuel storage container to
catch any residual fuel.
(3) Disconnect the electrical connector to the fuel
pump by depressing the integral spring and pulling
the connector away from the pump.
(4) Remove the dosing pump from the rubber iso-
lation.
INSTALLATION
(1) Mount the rubber isolation back onto the
splash shield mounting flanges at two locations.
(2) Connect fuel lines to the dosing pump and the
heater unit. The connectors should point towards the
heater fuel line.
(3) Use aviation style clamps to attach the hose to
the fuel pump nipples(Refer to 24 - HEATING & AIR
CONDITIONING/CABIN HEATER/FUEL LINE -
INSTALLATION).
Fig. 1 Diesel Cabin Heater Exhaust System
1 - Mounting screws (3)
2 - Steel heater exhaust pipe
3 - Exhaust clamp (2)
4 - Flexible heater exhaust pipe5 - Heater and heater shield
6 - Exhaust pipe mounting clips (3)
RSDIESEL SUPPLEMENTAL HEATER - DCHA - BUX24 - 111
EXHAUST TUBE (Continued)
ProCarManuals.com
Page 2355 of 2399
(4) Connect the electrical connector to the fuel
pump by depressing the integral spring and pushing
the connector towards the dosing pump. Pull the con-
nector towards the heater to verify the installation.
(5) Verify function of the heater.
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 cabin heater line removed from 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 line shows any signs of being restricted
after air pressure is applied, then the fuel line should
be replaced.
(5) Install the cabin heater line(Refer to 24 -
HEATING & AIR CONDITIONING/CABIN HEAT-
ER/FUEL LINE - INSTALLATION).
(6) Verify function of the heater.
REMOVAL
(1) Elevate vehicle on a lift taking note of the
heater exhaust tube flexible section.
(2) Remove clamps on dosing pump end of fuel line
and separate line from pump (Fig. 3).
NOTE: Have an approved fuel holding device ready
to capture any diesel fuel that drains from fuel line
or heater unit.
(3) Remove clamp from fuel line at fuel tank con-
nection and separate line from tank.
(4) Remove any retaining clips and remove line
from vehicle.
INSTALLATION
WARNING: DO NOT OPERATE THE DCHA IN AN
ENCLOSED AREA SUCH AS A GARAGE THAT
DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. ALWAYS VENT THE DCHA'S EXHAUST WHEN
OPERATING THE DCHA. FAILURE TO FOLLOW
THESE INSTRUCTIONS MAY RESULT IN PERSONAL
INJURY OR DEATH.
Fig. 2 Dosing Pump Fuel Line
1 - Fuel Line
2 - Retaining Clamps3 - Dosing Pump
4 - Heater Unit Air Intake Pipe
24 - 112 DIESEL SUPPLEMENTAL HEATER - DCHA - BUXRS
FUEL DOSING PUMP (Continued)
ProCarManuals.com
Page 2357 of 2399
(7) With the DRBIIItin Cabin Heater, select Sys-
tem 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 DRBIIItkey pad to exit the Dosing Pump Prime.
The Dosing Pump priming procedure is now com-
plete.
HEATER UNIT
REMOVAL
WARNING: ALLOW THE DCHA TO COOL BEFORE
PERFORMING A COMPONENT INSPECTION/REPAIR
OR REPLACEMENT. FAILURE TO FOLLOW THESE
INSTRUCTIONS MAY RESULT IN PERSONAL
INJURY.
WARNING: ALLOW THE EXHAUST SYSTEM TO
COOL BEFORE PERFORMING A COMPONENT
INSPECTION/REPAIR OR REPLACEMENT. FAILURE
TO FOLLOW THESE INSTRUCTION MAY RESULT IN
PERSONAL INJURY.
(1) Elevate the vehicle on a hoist/lift taking note of
heater exhaust tube flexible section.
(2) Drain 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 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 cross member at two locations.
(6) Disconnect the electrical connector from the
body harness near the toe board cross member and
rail.
(7) Remove the wiring harness from the toe board
cross member(Refer to 24 - HEATING & AIR CON-
DITIONING/CABIN HEATER/HEATER UNIT -
REMOVAL).
(8) Open the fuel fill 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 M8 fasteners at the rail. Take
care to notice that the exhaust tube bracket tab is on
top of the heater bracket.(10) Remove the heater exhaust tube flex section
from the exhaust tube by loosening the M6 bolt of
the clamp assembly. 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 cross member.
(12) Loosen the remaining M6 and M8 fasteners
which mount the exhaust tube assembly to the vehi-
cle.
(a) Install a suitable cabin heater support device
under the cabin heater and secure the cabin heater
to the device.
(13) Loosen the remaining three M6 fasteners to
the cross members.
(14) Remove the loosened fasteners that support
the heater while supporting the weight of the heater.
(15) Swing the unit mounting bracket from
between the exhaust bracket and rail mounting loca-
tion. Drain any residual coolant from the heater unit.
(16) Lower the cabin heater and remove from the
supporting device and place on a suitable work area.
INSTALLATION
(1) Install the unit mounting bracket between the
exhaust bracket and the rail mounting location.
(2) Install the fasteners that support the heater
while supporting the weight of the heater.
(3) Install the three M6 fasteners to the cross
members. Tighten the M6 fasteners to 7 Nm (5 ft.
lbs.).
(4) Tighten the remaining M6 fasteners to 7 Nm (5
ft. lbs.) and the M8 fasteners to 23 Nm (17 ft. lbs.)
which mount the exhaust tube assembly to the vehi-
cle.
(5) Install the seat hex nut at the heater mounting
flange to the cross members. Tighten to 60 Nm (44 ft.
lbs.)
(6) Install the heater exhaust tube flex section to
the exhaust tube by tightening the M6 bolt of the
clamp assembly. Install the hose to the exhaust tube.
(7) Tighten the two M8 fasteners at the rail to 23
Nm (17 ft. lbs.). Taking care so that the exhaust tube
bracket tab is on the top of the heater bracket.
(8) Install the wiring harness(Refer to 24 - HEAT-
ING & AIR CONDITIONING/CABIN HEATER/
HEATER UNIT - INSTALLATION).
(9) Tighten the hose and tube assembly to the toe-
board cross member at two locations.
(10) Install the second hose to the underbody hose
and tube assembly.
(11) 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.
24 - 114 DIESEL SUPPLEMENTAL HEATER - DCHA - BUXRS
FUEL LINE (Continued)
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Page 2360 of 2399
EMISSIONS CONTROL
TABLE OF CONTENTS
page page
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - VEHICLE EMISSION
CONTROL INFORMATION LABEL..........1
DESCRIPTION - TRIP DEFINITION.........1
DESCRIPTION - MONITORED COMPONENT . 1
OPERATION - NON-MONITORED CIRCUITS . . 5
DESCRIPTION - MONITORED SYSTEMS....6DESCRIPTION - HIGH AND LOW LIMITS....9
OPERATION
OPERATION - SYSTEM..................9
DRB IIITSTATE DISPLAY TEST MODE.....10
EVAPORATIVE EMISSIONS................11
EXHAUST GAS RECIRCULATION...........20
ON-BOARD DIAGNOSTICS................24
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - VEHICLE EMISSION CONTROL
INFORMATION LABEL
All models have a Vehicle Emission Control Infor-
mation (VECI) Label. Chrysler permanently attaches
the label in the engine compartment. It cannot be
removed without defacing information and destroying
the label.
The label contains the vehicle's emission specifica-
tions and vacuum hose routings. All hoses must be
connected and routed according to the label.
DESCRIPTION - TRIP DEFINITION
A ªTripº means vehicle operation (following an
engine-off period) of duration and driving mode such
that all components and systems are monitored at
least once by the diagnostic system. The monitors
must successfully pass before the PCM can verify
that a previously malfunctioning component is meet-
ing the normal operating conditions of that compo-
nent. For misfire or fuel system malfunction, the
MIL may be extinguished if the fault does not recur
when monitored during three subsequent sequential
driving cycles in which conditions are similar to
those under which the malfunction was first deter-
mined.
Anytime the MIL is illuminated, a DTC is stored.
The DTC can self erase only after the MIL has been
extinguished. Once the MIL is extinguished, the
PCM must pass the diagnostic test for the most
recent DTC for 40 warm-up cycles (80 warm-up
cycles for the Fuel System Monitor and the Misfire
Monitor). A warm-up cycle can best be described by
the following:
²The engine must be running²A rise of 40ÉF in engine temperature must occur
from the time when the engine was started
²
Engine coolant temperature must crossover 160ÉF
²A ªdriving cycleº that consists of engine start up
and engine shut off.
Once the above conditions occur, the PCM is con-
sidered to have passed a warm-up cycle. Due to the
conditions required to extinguish the MIL and erase
the DTC, it is most important that after a repair has
been made, all DTC's be erased and the repair veri-
fied by running 1±good trip.
DESCRIPTION - MONITORED COMPONENT
There are several components that will affect vehi-
cle emissions if they malfunction. If one of these com-
ponents malfunctions the Malfunction Indicator
Lamp (Check Engine) will illuminate.
Some of the component monitors are checking for
proper operation of the part. Electrically operated
components now have input (rationality) and output
(functionality) checks. Previously, a component like
the Throttle Position sensor (TPS) was checked by
the PCM for an open or shorted circuit. If one of
these conditions occurred, a DTC was set. Now there
is a check to ensure that the component is working.
This is done by watching for a TPS indication of a
greater or lesser throttle opening than MAP and
engine rpm indicate. In the case of the TPS, if engine
vacuum is low and engine rpm is 1600 or greater and
the TPS indicates a small throttle opening, a DTC
will be set. The same applies to low vacuum and
1600 rpm.
Any component that has an associated limp in will
set a fault after 1 trip with the malfunction present.
Refer to the Diagnostic Trouble Codes Description
Charts (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL
MODULE - DESCRIPTION) and the appropriate
Powertrain Diagnostic Procedure Manual for diag-
nostic procedures.
RSEMISSIONS CONTROL25-1
ProCarManuals.com
Page 2361 of 2399
The following is a list of the monitored compo-
nents:
²Comprehensive Components
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
COMPREHENSIVE COMPONENTS
Along with the major monitors, OBD II requires
that the diagnostic system monitor any component
that could affect emissions levels. In many cases,
these components were being tested under OBD I.
The OBD I requirements focused mainly on testing
emissions-related components for electrical opens and
shorts.
However, OBD II also requires that inputs from
powertrain components to the PCM be tested for
rationality, and that outputs to powertrain compo-
nents from the PCM be tested forfunctionality.
Methods for monitoring the various Comprehensive
Component monitoring include:
(1) Circuit Continuity
²Open
²Shorted high
²Shorted to ground
(2) Rationality or Proper Functioning
²Inputs tested for rationality
²Outputs tested for functionality
NOTE: Comprehensive component monitors are
continuous. Therefore, enabling conditions do not
apply.
Input RationalityÐWhile input signals to the
PCM are constantly being monitored for electrical
opens and shorts, they are also tested for rationality.
This means that the input signal is compared against
other inputs and information to see if it makes sense
under the current conditions.
PCM sensor inputs that are checked for rationality
include:
²Manifold Absolute Pressure (MAP) Sensor
²Oxygen Sensor (O2S)
²Engine Coolant Temperature (ECT) Sensor
²Camshaft Position (CMP) Sensor
²Vehicle Speed Sensor
²Crankshaft Position (CKP) Sensor
²Intake/inlet Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Ambient/Battery Temperature Sensors
²Power Steering Switch
²Oxygen Sensor Heater
²Engine Controller
²Brake Switch
²Leak Detection Pump Switch (if equipped)
²P/N Switch
²Trans ControlsOutput FunctionalityÐPCM outputs are tested
for functionality in addition to testing for opens and
shorts. When the PCM provides a voltage to an out-
put component, it can verify that the command was
carried out by monitoring specific input signals for
expected changes. For example, when the PCM com-
mands the Idle Air Control (IAC) Motor to a specific
position under certain operating conditions, it expects
to see a specific (target) idle speed (RPM). If it does
not, it stores a DTC.
PCM outputs monitored for functionality include:
²Fuel Injectors
²Ignition Coils
²Torque Converter Clutch Solenoid
²Idle Air Control
²Purge Solenoid
²EGR Solenoid (if equipped)
²LDP Solenoid (if equipped)
²Radiator Fan Control
²Trans Controls
OXYGEN SENSOR (O2S) MONITOR
DESCRIPTIONÐEffective 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 operating temperature 300É to 350ÉC
(572É to 662ÉF), the sensor generates a voltage that
is inversely proportional to the amount of oxygen in
the exhaust. When there is a large amount of oxygen
in the exhaust caused by a lean condition, the sensor
produces a low voltage, below 450 mV. When the oxy-
gen content is lower, caused by a rich condition, the
sensor produces a higher voltage, above 450mV.
The information obtained by the sensor is used to
calculate the fuel injector pulse width. The PCM is
programmed to maintain the optimum air/fuel ratio.
At this mixture ratio, the catalyst works best to
remove hydrocarbons (HC), carbon monoxide (CO)
and nitrous oxide (NOx) from the exhaust.
The O2S is also the main sensing element for the
EGR (if equipped), Catalyst and Fuel Monitors.
The O2S may fail in any or all of the following
manners:
²Slow response rate (Big Slope)
²Reduced output voltage (Half Cycle)
²Heater Performance
Slow Response Rate (Big Slope)ÐResponse rate
is the time required for the sensor to switch from
lean to rich signal output once it is exposed to a
richer than optimum A/F mixture or vice versa. As
the PCM adjusts the air/fuel ratio, the sensor must
be able to rapidly detect the change. As the sensor
ages, it could take longer to detect the changes in the
oxygen content of the exhaust gas. The rate of
change that an oxygen sensor experiences is called
25 - 2 EMISSIONS CONTROLRS
EMISSIONS CONTROL (Continued)
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Page 2362 of 2399
ªBig Slopeº. The PCM checks the oxygen sensor volt-
age in increments of a few milliseconds.
Reduced Output Voltage (Half Cycle)ÐThe
output voltage of the O2S ranges from 0 to 1 volt. A
good sensor can easily generate any output voltage in
this range as it is exposed to different concentrations
of oxygen. To detect a shift in the A/F mixture (lean
or rich), the output voltage has to change beyond a
threshold value. A malfunctioning sensor could have
difficulty changing beyond the threshold value. Each
time the voltage signal surpasses the threshold, a
counter is incremented by one. This is called the Half
Cycle Counter.
Heater PerformanceÐThe heater is tested by a
separate monitor. Refer to the Oxygen Sensor Heater
Monitor.
OPERATIONÐAs the Oxygen Sensor signal
switches, the PCM monitors the half cycle and big
slope signals from the oxygen sensor. If during the
test neither counter reaches a predetermined value, a
malfunction is entered and Freeze Frame data is
stored. Only one counter reaching its predetermined
value is needed for the monitor to pass.
The Oxygen Sensor Monitor is a two trip monitor
that is tested only once per trip. When the Oxygen
Sensor fails the test in two consecutive trips, the
MIL is illuminated and a DTC is set. The MIL is
extinguished when the Oxygen Sensor monitor
passes in three consecutive trips. The DTC is erased
from memory after 40 consecutive warm-up cycles
without test failure.
Enabling ConditionsÐThe following conditions
must typically be met for the PCM to run the oxygen
sensor monitor:
²Battery voltage
²Engine temperature
²Engine run time
²Engine run time at a predetermined speed
²Engine run time at a predetermined speed and
throttle opening
²Transmission in gear and brake depressed (auto-
matic only)
²Fuel system in Closed Loop
²Long Term Adaptive (within parameters)
²Power Steering Switch in low PSI (no load)
²Engine at idle
²Fuel level above 15%
²Ambient air temperature
²Barometric pressure
²Engine RPM within acceptable range of desired
idle
Pending ConditionsÐThe Task Manager typi-
cally does not run the Oxygen Sensor Monitor if over-
lapping monitors are running or the MIL is
illuminated for any of the following:
²Misfire Monitor²Front Oxygen Sensor and Heater Monitor
²MAP Sensor
²Vehicle Speed Sensor
²Engine Coolant Temperature Sensor
²Throttle Position Sensor
²Engine Controller Self Test Faults
²Cam or Crank Sensor
²Injector and Coil
²Idle Air Control Motor
²EVAP Electrical
²EGR Solenoid Electrical (if equipped)
²Intake/inlet Air Temperature
²5 Volt Feed
ConflictÐThe Task Manager does not run the
Oxygen Sensor Monitor if any of the following condi-
tions are present:
²A/C ON (A/C clutch cycling temporarily sus-
pends monitor)
²Purge flow in progress
²Ethanel content learn is takeng place and the
ethenal used once flag is set (if equipped)
SuspendÐThe Task Manager suspends maturing
a fault for the Oxygen Sensor Monitor if any of the
following are present:
²Oxygen Sensor Heater Monitor, Priority 1
²Misfire Monitor, Priority 2
OXYGEN SENSOR HEATER MONITOR
DESCRIPTIONÐIf there is an oxygen sensor
(O2S) DTC as well as a O2S heater DTC, the O2S
fault MUST be repaired first. After the O2S fault is
repaired, verify that the heater circuit is operating
correctly.
The voltage readings taken from the O2S are very
temperature sensitive. The readings are not accurate
below 300ÉC. Heating of the O2S is done to allow the
engine controller to shift to closed loop control as
soon as possible. The heating element used to heat
the O2S must be tested to ensure that it is heating
the sensor properly.
The heater element itself is not tested. The sensor
output is used to test the heater by isolating the
effect of the heater element on the O2S output volt-
age from the other effects. The resistance is normally
between 100 ohms and 4.5 megaohms. When oxygen
sensor temperature increases, the resistance in the
internal circuit decreases. The PCM sends a 5 volts
biased signal through the oxygen sensors to ground
this monitoring circuit. As the temperature increases,
resistance decreases and the PCM detects a lower
voltage at the reference signal. Inversely, as the tem-
perature decreases, the resistance increases and the
PCM detects a higher voltage at the reference signal.
The O2S circuit is monitored for a drop in voltage.
OPERATIONÐThe Oxygen Sensor Heater Moni-
tor begins after the ignition has been turned OFF.
RSEMISSIONS CONTROL25-3
EMISSIONS CONTROL (Continued)
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Page 2364 of 2399
is enabled to run another test during that trip. When
the test fails 6 times, the counter increments to 3, a
malfunction is entered, and a Freeze Frame is stored,
the code is matured and the MIL is illuminated. If
the first test passes, no further testing is conducted
during that trip.
The MIL is extinguished after three consecutive
good trips. The good trip criteria for the catalyst
monitor is more stringent than the failure criteria. In
order to pass the test and increment one good trip,
the downstream sensor switch rate must be less than
45% of the upstream rate. The failure percentages
are 59% respectively.
Enabling ConditionsÐThe following conditions
must typically be met before the PCM runs the cat-
alyst monitor. Specific times for each parameter may
be different from engine to engine.
²Accumulated drive time
²Enable time
²Ambient air temperature
²Barometric pressure
²Catalyst warm-up counter
²Engine coolant temperature
²Vehicle speed
²MAP
²RPM
²Engine in closed loop
²Fuel level
Pending ConditionsÐ
²Misfire DTC
²Front Oxygen Sensor Response
²Front Oxygen Sensor Heater Monitor
²Front Oxygen Sensor Electrical
²Rear Oxygen Sensor Rationality (middle check)
²Rear Oxygen Sensor Heater Monitor
²Rear Oxygen Sensor Electrical
²Fuel System Monitor
²All TPS faults
²All MAP faults
²All ECT sensor faults
²Purge flow solenoid functionality
²Purge flow solenoid electrical
²All PCM self test faults
²All CMP and CKP sensor faults
²All injector and ignition electrical faults
²Idle Air Control (IAC) motor functionality
²Vehicle Speed Sensor
²Brake switch (auto trans only)
²Intake air temperature
ConflictÐThe catalyst monitor does not run if any
of the following are conditions are present:
²EGR Monitor in progress (if equipped)
²Fuel system rich intrusive test in progress
²EVAP Monitor in progress
²Time since start is less than 60 seconds
²Low fuel level-less than 15 %²Low ambient air temperature
²Ethanel content learn is takeng place and the
ethenal used once flag is set
SuspendÐThe Task Manager does not mature a
catalyst fault if any of the following are present:
²Oxygen Sensor Monitor, Priority 1
²Oxygen Sensor Heater, Priority 1
²EGR Monitor, Priority 1 (if equipped)
²EVAP Monitor, Priority 1
²Fuel System Monitor, Priority 2
²Misfire Monitor, Priority 2
OPERATION - NON-MONITORED CIRCUITS
The PCM does not monitor all circuits, systems
and conditions that could have malfunctions causing
driveability problems. However, problems with these
systems may cause the PCM to store diagnostic trou-
ble codes for other systems or components. For exam-
ple, a fuel pressure problem will not register a fault
directly, but could cause a rich/lean condition or mis-
fire. This could cause the PCM to store an oxygen
sensor or misfire diagnostic trouble code.
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 misfire detection.
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.
RSEMISSIONS CONTROL25-5
EMISSIONS CONTROL (Continued)
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