coolant CHRYSLER VOYAGER 1996 Service Manual
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Page 1868 of 1938
SAFETY PRECAUTIONS AND WARNINGS
WARNING: WEAR EYE PROTECTION WHEN SER-
VICING THE AIR CONDITIONING REFRIGERANT
SYSTEM. SERIOUS EYE INJURY CAN RESULT
FROM EYE CONTACT WITH REFRIGERANT. IF EYE
CONTACT IS MADE, SEEK MEDICAL ATTENTION
IMMEDIATELY.
DO NOT EXPOSE REFRIGERANT TO OPEN
FLAME. POISONOUS GAS IS CREATED WHEN
REFRIGERANT IS BURNED. AN ELECTRONIC TYPE
LEAK DETECTOR IS RECOMMENDED.
LARGE AMOUNTS OF REFRIGERANT RELEASED
IN A CLOSED WORK AREA WILL DISPLACE THE
OXYGEN AND CAUSE SUFFOCATION.
THE EVAPORATION RATE OF REFRIGERANT AT
AVERAGE TEMPERATURE AND ALTITUDE IS
EXTREMELY HIGH. AS A RESULT, ANYTHING THAT
COMES IN CONTACT WITH THE REFRIGERANT
WILL FREEZE. ALWAYS PROTECT SKIN OR DELI-
CATE OBJECTS FROM DIRECT CONTACT WITH
REFRIGERANT. R-134a SERVICE EQUIPMENT OR
VEHICLE A/C SYSTEM SHOULD NOT BE PRES-
SURE TESTED OR LEAK TESTED WITH COM-
PRESSED AIR.
SOME MIXTURES OF AIR and R-134a HAVE BEEN
SHOWN TO BE COMBUSTIBLE AT ELEVATED
PRESSURES. THESE MIXTURES ARE POTENTIALLY
DANGEROUS AND MAY RESULT IN FIRE OR
EXPLOSION CAUSING INJURY OR PROPERTY
DAMAGE.
ANTIFREEZE IS AN ETHYLENE GLYCOL BASE
COOLANT AND IS HARMFUL IF SWALLOWED OR
INHALED. SEEK MEDICAL ATTENTION IMMEDI-
ATELY IF SWALLOWED OR INHALED. DO NOT
STORE IN OPEN OR UNMARKED CONTAINERS.
WASH SKIN AND CLOTHING THOROUGHLY AFTER
COMING IN CONTACT WITH ETHYLENE GLYCOL.
KEEP OUT OF REACH OF CHILDREN AND PETS.
DO NOT OPEN A COOLING SYSTEM WHEN THE
ENGINE IS AT RUNNING TEMPERATURE. PER-
SONAL INJURY CAN RESULT.
CAUTION: The engine cooling system is designed
to develop internal pressure of 97 to 123 kPa (14 to
18 psi). Allow the vehicle to cool a minimum of 15
minutes before opening the cooling system. Refer
to Group 7, Cooling System.
DESCRIPTION AND OPERATION
AIR DISTRIBUTION DUCTS
The air distribution ducts for the A/C, Heater,
Defroster, and Second Seating Air Distribution arenot serviceable in vehicle. The procedures for service
of these ducts are covered in Group 8E, Instrument
Panel and Gauges.
The only ducts that are serviceable in the vehicle
are the side window demister ducts and the ducts
that feed the front door outlets for the first rear pas-
senger(s) seating. To service the door ducts refer to
Group 23, Body.
A/C PRESSURE TRANSDUCER
The A/C Pressure Transducer (Fig. 1) monitors the
refrigerant gas pressure on the high side of the sys-
tem. The transducer is located on the liquid line. The
pressure transducer turns off the voltage to the com-
pressor clutch coil when refrigerant gas pressure
drops to levels that could damage the compressor.
The transducer also is used to adjust condenser fan
speeds and will turn off compressor at high refriger-
ant pressures. The pressure transducer is a sealed
factory calibrated unit. It must be replaced if defec-
tive. O-ring replacement is required whenever the
pressure transducer is serviced. Be sure to use the
O-ring specified for the transducer.
A/C SERVICE PORTS
The A/C service port valve cores are located within
the A/C lines. The High Side (Discharge) valve ser-
vice port is located on the liquid line near the right
strut tower. The Low Side (Suction) valve service
port is located on the suction line near the compres-
sor.
The High Side service port is a two piece port and
is serviceable. The Low Side service port is not ser-
viceable, and the suction line would have to be
replaced.
COMPRESSOR
The A/C compressor for the 2.5L Turbo Diesel, is
located on the front side of the engine block. It is
mounted to the engine block by four bolts. The com-
Fig. 1 A/C Pressure Transducer
24 - 2 HEATING AND AIR CONDITIONINGNS/GS
GENERAL INFORMATION (Continued)
Page 1871 of 1938
capacity of the system and consequently result in
higher discharge air temperatures.
NOTE: The oil used in the Denso 2.5L Turbo Diesel
and the Denso 2.0L gasoline engine compressors is
ND-8 PAG R134a refrigerant oil. Only refrigerant oil
of the same type should be used to service the sys-
tem. Do not use any other oil. The oil container
should be kept tightly capped until it is ready for
use. Tightly cap afterwards to prevent contamina-
tion from dirt and moisture. Refrigerant oil will
quickly absorb any moisture it comes in contact
with. Special effort must be used to keep all R-134a
system components moisture-free. Moisture in the
oil is very difficult to remove and will cause a reli-
ability problem with the compressor.
It will not be necessary to check oil level in the
compressor or to add oil unless there has been an oil
loss. Oil loss at a leak point will be evident by the
presence of a wet, shiny surface around the leak.
REFRIGERANT OIL LEVEL CHECK
When an air conditioning system is first assem-
bled, all components (except the compressor) are
refrigerant oil free. After the system has been
charged with R134a refrigerant and operated, the oil
in the compressor is dispersed through the lines and
components. The evaporator, condenser, and filter-
drier will retain a significant amount of oil, refer to
the Refrigerant Oil Capacities chart. When a compo-
nent is replaced, the specified amount of refrigerant
oil must be added. When the compressor is replaced,
the amount of oil that is retained in the rest of the
system must be drained from the replacement com-
pressor. When a line or component has ruptured and
oil has escaped, the compressor should be removed
and drained. The compressor is drained through the
suction port or by removing the sump bolt on top of
the compressor, refer to Compressor Removal and
Installation procedures. The filter-drier must be
replaced along with the ruptured part. The oil capac-
ity of the system, minus the amount of oil still in the
remaining components, can be measured and poured
into the suction port of the compressor.
Example: The evaporator retains 50 ml (1.7 oz.).
The condenser retains 30 ml (1 oz) of oil, and system
capacity may be 220 ml (7.40 oz) of oil.
220 ml minus 90 ml = 130 ml (4.40 oz.).
CAUTION: The refrigerant oil used in a R-134a A/C
system is unique. Use only oils which were designed
to work with R-134a refrigerant. The oil designated
for the Denso 2.5L Turbo Diesel and Denso 2.0L gas-
oline engine compressors is ND-8 PAG compressor
oil. For gasoline vehicles still using R-12 refrigerant,
use ND8 PAG compressor oil.
SERVICING REFRIGERANT OIL LEVEL
(1) Using a refrigerant recovery machine, remove
refrigerant from the A/C system.
(2) Remove refrigerant lines from A/C compressor.
(3) Remove compressor from vehicle.
(4) From suction port on top of compressor, drain
refrigerant oil from compressor.
(5) Add system capacity minus the capacity of
components that have not been replaced through suc-
tion port on compressor. Refer to the Refrigerant Oil
Capacity Chart.
(6) Install compressor, connect refrigerant lines,
evacuate, and charge refrigerant system.
DIAGNOSIS AND TESTING
ACTUATOR CALIBRATION/DIAGNOSTICS AND
COOLDOWN TEST
GENERAL INFORMATION
If the HVAC control module is replaced, the Cali-
bration Diagnostic and Cooldown tests will need to
be performed. Once this group of tests have success-
fully passed, they can be performed individually. The
engine must be running during the test to provide
hot coolant for the heater, A/C compressor operation
and to assure that the actuators are calibrated cor-
rectly. The HVAC control module is capable of trou-
bleshooting the system in approximately 120 seconds.
If a condition is detected, an error code is displayed.
The error code cannot be erased until the condition is
repaired and the diagnostic test is performed. Check
wire before replacing components, refer to Group 8W,
Wiring Diagrams.
CAUTION: Do not remove the actuators from the
Heater-A/C unit assembly with power applied.
Removal should only be done with the Ignition OFF.
The actuators have no mechanical stops to limit the
travel. If the actuator rotates and is not connected to
the unit assembly, it will become out of calibration.
ACTUATOR CALIBRATION
Mode, Blend and Zone (if equipped) door calibra-
tion compensates for mechanical variations in the
REFRIGERANT OIL CAPACITIES
REFRIGERANT OIL CAPACITIES
COMPONENT ML OZ
Compressor 135 ml 4.5 oz
Filter-Drier 30 ml 1.0 oz
Condenser 30 ml 1.0 oz
Evaporator 50 ml 1.7 oz
NS/GSHEATING AND AIR CONDITIONING 24 - 5
DESCRIPTION AND OPERATION (Continued)
Page 1880 of 1938
(6) If coil current reads zero, the coil is open and
should be replaced. If the ammeter reading is 4
amperes or more, the coil is shorted and should be
replaced. If the coil voltage is not within two volts of
the battery voltage, test clutch coil feed circuit for
excessive voltage drop.
EXPANSION VALVE
NOTE: Special effort must be used to keep all
R-134a system components moisture-free. Moisture
in the oil is very difficult to remove and will cause a
reliability problem with the compressor.
TESTS
NOTE: Expansion valve tests should be performed
after compressor tests.
Review Safety Precautions and Warnings in this
group. The work area and vehicle temperature must
be 21ÉC to 27ÉC (70ÉF to 85ÉF). To test the expansion
valve:
NOTE: Liquid CO2 is required to test the expansion
valve. It is available from most welding supply facil-
ities. CO2 is also available from companies which
service and sell fire extinguishers.
(1) Connect a charging station or manifold gauge
set to the refrigerant system service ports. Verify the
refrigerant charge level.
(2) Close all doors, windows and vents to the pas-
senger compartment.
(3) Set heater A/C control to A/C, full heat,
FLOOR, and high blower.
(4) Start the engine and allow to idle (1000 rpm).
After the engine has reached running temperature,
allow the passenger compartment to heat up. This
will create the need for maximum refrigerant flow
into the evaporator.
(5) I
f the refrigerant charge is sufficient, discharge
(high pressure) gauge should read 965 to 1655 kPa (140
to 240 psi). Suction (low pressure) gauge should read
140 kPa to 207 kPa (20 psi to 30 psig). If system cannot
achieve proper pressure readings, replace the expan-
sion valve. If pressure is correct, proceed with test.
WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO2 PERSONAL INJURY CAN RESULT.
(6) If suction side low pressure is within specified
range, freeze the expansion valve control head for 30
seconds. Use a super cold substance (liquid CO2).Do
not spray R-134a Refrigerant on the expansion
valve for this test.Suction side low pressure should
drop by 10 psi. If not, replace expansion valve.(7) Allow expansion valve to thaw. The low pres-
sure gauge reading should stabilize at 140 kPa to
240 kPa (20 psi to 30 psig). If not, replace expansion
valve.
(8) When expansion valve test is complete, test
A/C overall performance. Remove all test equipment
before returning vehicle to use.
HEATER PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
Review Safety Precautions and Warnings in this
group before performing the following procedures.
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.
WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing cap. Place a rag over the cap and
turn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.
MAXIMUM HEATER OUTPUT: TEST AND
ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference chart.
If the floor outlet air temperature is insufficient,
refer to Group 7, Cooling Systems for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
TEMPERATURE REFERENCE CHART
AMBIENT TEMP.MINIMUM FLOOR
OUTLET TEMP.
CELSIUS FAHRENHEIT CELSIUS FAHRENHEIT
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
24 - 14 HEATING AND AIR CONDITIONINGNS/GS
DIAGNOSIS AND TESTING (Continued)
Page 1881 of 1938
POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW
(1) Pinched or kinked heater hoses.
(2) Improper heater hose routing.
(3) Plugged heater hoses or supply and return
ports at cooling system connections, refer to Group 7,
Cooling System.
(4) Plugged heater core.
(5) Air locked heater core.
(6) If coolant flow is verified and outlet tempera-
ture is insufficient, a mechanical problem may exist.
POSSIBLE LOCATION OR CAUSE OF
INSUFFICIENT HEAT
(1) Obstructed cowl air intake.
(2) Obstructed heater system outlets.
(3) Blend-air door not functioning properly.
TEMPERATURE CONTROL
If temperature cannot be adjusted with the TEMP
lever on the control panel, the following could require
service:
(1) Blend-air door binding.
(2) Faulty blend-air door motor.
(3) Improper engine coolant temperature.
(4) Faulty Instrument Panel Control.
SYSTEM CHARGE LEVEL TEST
The procedure below should be used to check
and/or fill the refrigerant charge in the air condition-
ing system.
NOTE: The amount of R134a refrigerant that the air
conditioning system holds is 0.96 kg (34 oz. or 2.13
lbs.).
NOTE: Low Charge, condition may be described
as:
²Loss of A/C performance
²Fog from A/C outlets
²evaporator may have a HISS sound
There are two different ways the system can be
tested:
²With a scan tool (DRB), thermocouple and the
Charge Determination Graph. Use the scan tool
(DRB) diagnostic topic: Engine±System Monitors, A/C
Pressure.
²Using a manifold gauge set, a thermocouple and
the Charge Determination Graph.
It is recommended to use the gauges or reclaim/re-
cycle equipment.
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAEREQUIREMENTS TO DISCHARGE R-134a SYSTEM. IF
ACCIDENTAL SYSTEM DISCHARGE OCCURS, VEN-
TILATE WORK AREA BEFORE RESUMING SERVICE.
R-134a SERVICE EQUIPMENT OR VEHICLE A/C
SYSTEM SHOULD NOT BE PRESSURE TESTED OR
LEAK TESTED WITH COMPRESSED AIR. SOME
MIXTURES OF AIR/R-134a HAVE BEEN SHOWN TO
BE COMBUSTIBLE AT ELEVATED PRESSURES.
THESE MIXTURES ARE POTENTIALLY DANGER-
OUS AND MAY RESULT IN FIRE OR EXPLOSION
CAUSING INJURY OR PROPERTY DAMAGE.
(1) Establish your preferred method of measuring
liquid line pressure. Use a manifold gauge set or a
DRB scan tool.
(2) A
ttach a clamp-on thermocouple (Professional
Service Equipment 66-324-0014 or 80PK-1A) or equiv-
alent to the liquid line. It must be placed as close to
the A/C Pressure Transducer as possible to observe liq-
uid line temperature. Refer to ªThermocouple Probeº in
this section for more information on probe.
(3) The vehicle must be in the following modes:
²Transaxle in Park
²Engine Idling at 700 rpm
²A/C Controls Set to Outside Air
²Panel Mode
²Full Cool
²High Blower motor, (vehicle equipped with rear
A/C turn rear blower motor ON HIGH)
²A/C Button in the ON position
²Vehicle Windows Open.
²Recirc. button turned OFF
(4) Operate system for a couple of minutes to allow
the system to stabilize.
(5) Set system pressure to about 1793 kPa (260
psi) by placing a piece of cardboard over part of the
front side of the condenser. To place cardboard prop-
erly, remove the upper radiator-condenser cover.
Insert cardboard between condenser and radiator
front. This will maintain a constant pressure.
(6) Observe Liquid Line pressure and Liquid line
temperature. Using theCharge Determination
Chartdetermine where the system is currently oper-
ating. If the system is in the undercharged region,
ADD 0.057 Kg. (2 oz.) to the system and recheck
readings. If the system is in the overcharged region,
RECLAIM 0.057 Kg. (2 oz.) from the system and
recheck readings. Continue this process until the sys-
tem readings are in the proper charge area on the
Charge Determination Chart.
(7) The same procedure can be performed using
the scan tool (DRB). To determine liquid line pres-
sure, attach the scan tool, go to System Moni-
tors±A/C Pressure. Observe liquid line pressure from
A/C Pressure Transducer on digital display and digi-
tal thermometer. Refer toCharge Determination
Chartand determine where the system is operating.
NS/GSHEATING AND AIR CONDITIONING 24 - 15
DIAGNOSIS AND TESTING (Continued)
Page 1892 of 1938
(2) Hand-start the stud into the expansion valve
and torque to7-11N´m(64-96in.lbs.).
(3) Carefully install the expansion valve to the
sealing plate. Install the two screws and tighten 8 to
14 N´m (70 to 130 in. lbs.) torque.
(4) Carefully install the refrigerant lines and seal-
ing plate to the expansion valve. Install the nut and
tighten 20 to 26 N´m (170 to 230 in. lbs.) torque.
(5) Install the ground wire at dash panel.
(6) Pull generator back into the proper position for
bracket mounting.
(7) Install generator field wire connector.
(8) Install the upper generator bracket.
(9) Install accessory drive belt.
(10) Evacuate and recharge system.
(11) After expansion valve is installed, the system
is charged, and leaks have checked repeat the A/C
performance check.
FILTER-DRIER ASSEMBLY
REMOVAL
WARNING: THE REFRIGERATION SYSTEM MUST
BE COMPLETELY EMPTY BEFORE PROCEEDING
WITH THIS OPERATION.
(1) Recover A/C system refrigerant.
(2) Remove liquid line at filter-drier (Fig. 21).
(3) Remove the (2) bolts holding filter-drier bracket
to radiator fan module bracket.
(4) Remove the lower liquid line at condenser.
(5) Remove the upper radiator crossmember.
(6) Pull up on radiator and slide filter-drier from
the mounting location.
INSTALLATION
(1) Before installation, replace both refrigerant
line O-rings. Then reverse the above procedures.
(2) Evacuate and recharge system.
HEATER A/C UNIT HOUSING
REMOVAL
WARNING: IF EQUIPPED WITH AIR CONDITIONING,
THE REFRIGERATION SYSTEM MUST BE COM-
PLETELY EMPTY BEFORE PROCEEDING.
(1) Set parking brake.
(2) Disconnect battery negative cable.
(3) Using a refrigerant recovery machine, remove
refrigerant from the A/C system.
(4) Remove wiper module. Refer to Group 8K,
Windshield Wipers and Washers.
(5) Drain engine coolant. Remove heater hoses at
the heater core, refer to Heater Hoses Removal and
Installation procedures. Plug coolant lines.(6) Remove suction and liquid lines at the expan-
sion valve (Fig. 27).
(7) Remove the Instrument Panel Assembly. Refer
to Group 8E, Instrument Panel and Systems.
(8) Remove heater ducts.
(9) Disconnect the two upper mounts from the
upper reinforcement and the lower mount from the
tunnel.
(10) Remove the (3) nuts (in the engine compart-
ment) securing the unit to the dash panel (Fig. 30).
(11) Disconnect the HVAC housing wiring harness.
(12) Pull the entire unit rearward until the studs
on the unit clear the dash panel. Drop the unit down.
Pull it rearward to remove it from vehicle.
INSTALLATION
(1) For installation of the assembly, reverse the
above procedures. Install new O-rings on plumbing
inlets
(2) Evacuate and recharge the A/C system.
(3) Perform HVAC control Calibration Diagnostic
and Cooldown test.
HEATER CORE
REMOVAL
(1) Drain coolant system.
(2) Remove left side lower column cover.
(3) Remove steering column assembly. Refer to
Group 19, Steering for service procedure.
(4) Remove ABS module, bracket and wiring (Fig.
31).
(5) Remove I/P to body harness interconnect and
bracket (Fig. 32).
(6) Remove lower silencer boot at base of steering
shaft (Fig. 33)
(7) Pinch off heater lines under the hood.
Fig. 30 HVAC Bolt-Up
24 - 26 HEATING AND AIR CONDITIONINGNS/GS
REMOVAL AND INSTALLATION (Continued)
Page 1894 of 1938
INSTALLATION
For installation, reverse the above procedures.
Install screws to retain heater core in housing.
Replace heater core tube inlet O-rings. Tighten
heater core tube retaining plate to 361 N´m (276
9 in. lbs.) torque.
HEATER HOSES
REMOVAL
NOTE: Review Safety Precautions and Warnings
before proceeding with this operation.
(1) Drain engine cooling system. Refer to Group 7,
Engine Cooling.
(2) Loosen clamps at each end of heater hose to be
removed (Fig. 38) and (Fig. 39).
CAUTION: When removing hoses from heater core
inlet or outlet nipples, do not use excessive force.
Heater core may become damaged and leak engine
coolant.(3) Carefully rotate hose back and forth while tug-
ging slightly away from connector nipple. If the hose
will not come off, slice the hose at the connector nip-
ple and peel off heater hose. This method will require
heater hose replacement.
INSTALLATION
For installation, reverse the above procedures.
LIQUID LINE
REMOVAL
(1) Disconnect the battery negative cable.
(2) Recover A/C system refrigerant.
(3) Remove ground wire at dash panel.
(4) Remove the nut retaining the refrigerant line
sealing plate to the expansion valve (Fig. 27).
(5) Remove the stud from the expansion valve (Fig.
28).
(6) Remove liquid line from expansion valve.
(7) Cover the openings to prevent contamination.
(8) Disconnect wire connector at pressure trans-
ducer.
(9) Remove liquid line mounting clip at right strut
tower.
(10) Using access slot between radiator crossmem-
ber and grille, loosen liquid line mounting plate at
filter-drier. Remove liquid line from filter-drier.
(11) Remove the old O-rings.
INSTALLATION
For installation, reverse the above procedures.
²Install the stud to the evaporator sealing plate
and tighten 7 to 11 N´m (64 to 96 in. lbs.) torque.
²Install new O-rings.
²Install two-piece line in place of original part.
²Assemble line halves after it is installed on vehi-
cle.
²Evacuate and recharge A/C system.
Fig. 37 Brake Pedal
Fig. 38 Upper Heater Hose
Fig. 39 Lower Heater Hose
24 - 28 HEATING AND AIR CONDITIONINGNS/GS
REMOVAL AND INSTALLATION (Continued)
Page 1906 of 1938
cranking. Whenever the Powertrain Control Module
(PCM) sets a Diagnostic Trouble Code (DTC) that
affects vehicle emissions, it illuminates the MIL. If a
problem is detected, the PCM sends a message over
the CCD Bus to the instrument cluster to illuminate
the lamp. The PCM illuminates the MIL only for
DTC's that affect vehicle emissions. The MIL stays
on continuously when the PCM has entered a
Limp-In mode or identified a failed emission compo-
nent or system. The MIL remains on until the DTC
is erased. Refer to the Diagnostic Trouble Code
charts in this group for emission related codes.
Also, the MIL either flashes or illuminates contin-
uously when the PCM detects active engine misfire.
Refer to Misfire Monitoring in this section.
Additionally, the PCM may reset (turn off) the MIL
when one of the following occur:
²PCM does not detect the malfunction for 3 con-
secutive trips (except misfire and fuel system moni-
tors).
²PCM does not detect a malfunction while per-
forming three successive engine misfire or fuel sys-
tem tests. The PCM performs these tests while the
engine is operating within6375 RPM of and within
10 % of the load of the operating condition at which
the malfunction was first detected.
STATE DISPLAY TEST MODE
The switch inputs to the Powertrain Control Mod-
ule (PCM) have two recognized states; HIGH and
LOW. For this reason, the PCM cannot recognize the
difference between a selected switch position versus
an open circuit, a short circuit, or a defective switch.
If the State Display screen shows the change from
HIGH to LOW or LOW to HIGH, assume the entire
switch circuit to the PCM functions properly. From
the state display screen, access either State Display
Inputs and Outputs or State Display Sensors.
STATE DISPLAY INPUTS AND OUTPUTS
Connect the DRB scan tool to the data link connec-
tor and access the State Display screen. Then access
Inputs and Outputs. The following list contains the
PCM system functions accessible through the Inputs
and Outputs screen.
Park/Neutral Switch
Speed Control Resume
Brake Switch
Speed Control On/Off
Speed Control Set
S/C Vent Solenoid
Actual S/C Vent Sol.
S/C Vacuum Solenoid
Actual S/C Vacuum Sol.
S/C Cancel
S/C Last Cutout
S/C Working Status
S/C Denied Status
A/C Clutch Relay
Actual A/C Clutch Relay
EGR Solenoid
Actual EGR Sol.
Automatic Shutdown Relay
Actual Automatic Shutdown Relay
Automatic Shutdown Relay Sense
Radiator Fan Control Module
Actual Radiator Fan Control Module
Duty Cycle EVAP Purge Solenoid
Actual EVAP Purge Sol.
Torque Converter Clutch Solenoid
Power Steering Switch
Closed Loop State
Current CMP Edge
Current CKP State
Current Sync State
Fuel Pump Relay
Actual Fuel Pump Relay
Ignition Sense (A21)
Malfunction Lamp
Limp-in Reason
STATE DISPLAY SENSORS
Connect the DRB scan tool to the vehicle and
access the State Display screen. Then access Sensor
Display. The following list contains the PCM system
functions accessible through the Sensor Display
screen.
Battery Temperature
Engine Coolant Temperature
Engine Coolant Temp Sensor
Throttle Position Volts
Minimum Throttle
Knock Sensor Volts
Battery Voltage
MAP Sensor Reading
Idle Air Control Motor Position
Fig. 1 Data Link (Diagnostic) Connector
25 - 2 EMISSION CONTROL SYSTEMSNS
DESCRIPTION AND OPERATION (Continued)
Page 1908 of 1938
DIAGNOSTIC TROUBLE CODE DESCRIPTIONS
HEX
CODEGENERIC
SCAN
TOOL
CODEDRB SCAN TOOL
DISPLAYDESCRIPTION OF DIAGNOSTIC
TROUBLE CODE
01 P0340 No Cam Signal at PCM No camshaft signal detected during engine
cranking.
02 P0601 Internal Controller Failure PCM Internal fault condition detected.
05 Charging System Voltage Too Low Battery voltage sense input below target charging
during engine operation. Also, no significant
change detected in battery voltage during active
test of generator output circuit.
06 Charging System Voltage Too High Battery voltage sense input above target charging
voltage during engine operation.
0A* Auto Shutdown Relay Control
CircuitAn open or shorted condition detected in the auto
shutdown relay circuit.
0B Generator Field Not Switching
ProperlyAn open or shorted condition detected in the
generator field control circuit.
0C P0743 Torque Converter Clutch Soleniod/
Trans Relay CircuitsAn open or shorted condition detected in the
torque converter part throttle unlock solenoid
control circuit (3 speed auto RH trans. only).
0E P1491 Rad Fan Control Relay Circuit An open or shorted condition detected in the low
speed radiator fan relay control circuit.
0F* Speed Control Solenoid Circuits An open or shorted condition detected in the
Speed Control vacuum or vent solenoid circuits.
10* A/C Clutch Relay Circuit An open or shorted condition detected in the A/C
clutch relay circuit.
11 P0403 EGR Solenoid Circuit An open or shorted condition detected in the EGR
transducer solenoid circuit.
12 P0443 EVAP Purge Solenoid Circuit An open or shorted condition detected in the duty
cycle purge solenoid circuit.
13 P0203 Injector #3 Control Circuit Injector #3 output driver does not respond properly
to the control signal.
14 P0202 Injector #2 Control Circuit Injector #2 output driver does not respond properly
to the control signal.
15 P0201 Injector #1 Control Circuit Injector #1 output driver does not respond properly
to the control signal.
19 P0505 Idle Air Control Motor Circuits A shorted or open condition detected in one or
more of the idle air control motor circuits.
1A P0122 Throttle Position Sensor Voltage
LowThrottle position sensor input below the minimum
acceptable voltage
1B P0123 Throttle Position Sensor Voltage
HighThrottle position sensor input above the maximum
acceptable voltage.
1E P0117 ECT Sensor Voltage Too Low Engine coolant temperature sensor input below
minimum acceptable voltage.
1F P0118 ECT Sensor Voltage Too High Engine coolant temperature sensor input above
maximum acceptable voltage.
25 - 4 EMISSION CONTROL SYSTEMSNS
DESCRIPTION AND OPERATION (Continued)
Page 1914 of 1938
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three port
solenoid is briefly energized. This initializes the
pump by drawing air into the pump cavity and also
closes the vent seal. During non test conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that prevents the diaphragm
assembly from reaching full travel. After the brief
initialization period, the solenoid is de-energized
allowing atmospheric pressure to enter the pump
cavity, thus permitting the spring to drive the dia-
phragm which forces air out of the pump cavity and
into the vent system. When the solenoid is energized
and de energized, the cycle is repeated creating flow
in typical diaphragm pump fashion. The pump is con-
trolled in 2 modes:
Pump Mode:The pump is cycled at a fixed rate to
achieve a rapid pressure build in order to shorten the
overall test length.
Test Mode:The solenoid is energized with a fixed
duration pulse. Subsequent fixed pulses occur when
the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5º H20.
The cycle rate of pump strokes is quite rapid as the
system begins to pump up to this pressure. As the
pressure increases, the cycle rate starts to drop off. If
there is no leak in the system, the pump would even-
tually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .020º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases due
to the flow through the purge system, the leak check
portion of the diagnostic is complete.
The canister vent valve will unseal the system
after completion of the test sequence as the pumpdiaphragm assembly moves to the full travel position.
Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicated
by a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
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 when 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 running
²A rise of 40ÉF in engine temperature must occur
from the time when the engine was started
²Engine coolant temperature must reach at least
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.
COMPONENT MONITORS
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
25 - 10 EMISSION CONTROL SYSTEMSNS
DESCRIPTION AND OPERATION (Continued)
Page 1923 of 1938
the amount of EGR supplied to the engine. This pro-
vides the correct amount of exhaust gas recirculation
for different operating conditions.
This system does not allow EGR at idle. The EGR
systems can operate at all coolant temperatures
above 60ÉF as long as the battery ambient tempera-
ture is above 7ÉF.
DIAGNOSIS AND TESTING
EGR SYSTEM ON-BOARD DIAGNOSTICS
The PCM performs an on-board diagnostic check of
the EGR system. The diagnostic system uses the
electronic EGR transducer for the system tests.
The diagnostic check activates only during selected
engine/driving conditions. When the conditions are
met, the PCM energizes the transducer solenoid to
disable the EGR. The PCM checks for a change in
the heated oxygen sensor signal. If the air-fuel mix-
ture goes lean, the PCM will attempt to enrichen the
mixture. The PCM registers a Diagnostic Trouble
Code (DTC) if the EGR system is not operating cor-
rectly. After registering a DTC, the PCM turns on the
malfunction indicator (Check Engine) lamp after 2
consecutive trips. There are 2 types of failures sensed
by the PCM. The first is a short or open in the elec-
trical solenoid circuit. The second is a mechanical
failure or loss of vacuum. The Malfunction Indicator
Lamp (MIL) indicates the need for service.
If a problem is indicated by the MIL and a DTC for
the EGR system is set, check for proper operation of
the EGR system. Use the System Test, EGR Gas
Flow Test. If the EGR system tests properly, check
the system using the DRB scan tool. Refer to
On-Board Diagnosis sections in this Group. Also,
refer to the DRB scan tool and the appropriate Pow-
ertrain Diagnostics Procedure manual.
EGR SYSTEM TEST
WARNING: APPLY PARKING BRAKE AND/OR
BLOCK WHEELS BEFORE TESTING THE EGR SYS-
TEM.
(1) Check the condition of all EGR system hoses
and tubes for leaks, cracks, kinks and hardening of
rubber hoses. Repair and correct these conditions
before performing any tests.
(2) Be sure the hoses at both the EGR valve and
EGR valve control are connected to the proper fit-
tings (Fig. 4).
(3) Be sure the electrical connector is firmly con-
nected at the valve control.
(4) To check EGR system operation, connect the
DRB scan tool to the 16±way data link connector.
The data link connector is located on the lower edge
of the instrument panel near the steering column.
Refer to the appropriate Powertrain Diagnostic Pro-
cedures service manual for operation of the DRB
scan tool when diagnosing the EGR system.
(5) After checking the system with the DRB scan
tool, proceed to the following EGR Valve Leakage and
EGR Valve Control Tests and repair as necessary.
Fig. 3 Electric EGR Transducer Assembly
Fig. 4 EGR Value and EGR Value ÐTypical
NSEMISSION CONTROL SYSTEMS 25 - 19
DESCRIPTION AND OPERATION (Continued)