Valve DODGE RAM 2001 Service Repair Manual

LOCATING VACUUM LEAKS
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 AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect the vacuum harness connector
located between the a/c heater control and the HVAC
housing under the instrument panel.
(2) Connect the test set vacuum hose probe to each
port in the HVAC housing half of the vacuum har-
ness connector, one port at a time, and pause after
each connection (Fig. 2). The test set gauge should
return to the 27 kPa (8 in. Hg.) setting shortly after
each connection is made. If OK, replace the faulty a/c
heater control. If not OK, go to step Step 3.
(3) Determine the vacuum line color of the vacuum
circuit that is leaking. To determine the vacuum line
colors, see the Vacuum Circuits chart (Fig. 3).
(4) Disconnect and plug the vacuum line from the
component (fitting, actuator, valve, switch, or reser-
voir) on the other end of the leaking circuit. Instru-
ment panel disassembly or removal may be necessary
to gain access to some components. Refer to Instru-
ment Panel System for the procedures.(5) Connect the test set hose or probe to the open
end of the leaking circuit. The test set gauge should
return to the 27 kPa (8 in. Hg.) setting shortly after
each connection is made. If OK, replace the faulty
disconnected component. If not OK, go to Step 6.
(6) To locate a leak in a vacuum line, leave one
end of the line plugged and connect the test set hose
or probe to the other end of the line. Run your fin-
gers slowly along the line while watching the test set
gauge. The vacuum reading will fluctuate when your
fingers contact the source of the leak. To repair the
vacuum line, cut out the leaking section of the line.
Then, insert the loose ends of the line into a suitable
length of 3 millimeter (0.125 inch) inside diameter
rubber hose.
Fig. 2 VACUUM CIRCUIT TEST
BR/BECONTROLS 24 - 11
CONTROLS (Continued)

(5) Remove the four screws that secure the a/c
heater control to the instrument panel (Fig. 19).
(6) Pull the a/c heater control assembly away from
the instrument panel far enough to access the con-
nections on the back of the control.
(7) Unplug the wire harness connector from the
back of the a/c heater control.
(8) On vehicles with heated mirrors, unplug the
heated mirror wire harness connector from the back
of the a/c heater control.
(9) Remove the a/c heater control from the instru-
ment panel.
INSTALLATION
(1) Plug the wire harness connector(s) into the
receptacle(s) on the back of the a/c heater control.
(2) Route the HVAC vacuum harness through the
hole in the reinforcement below the a/c heater control
opening of the instrument panel.
(3) Position the a/c heater control in the instru-
ment panel and secure it with four screws. Tighten
the screws to 2.2 N´m (20 in. lbs.).
(4) Reinstall the cluster bezel to the instrument
panel. Refer to Instrument Panel System for the pro-
cedures.
(5) Reach under the instrument panel to reinstall
the a/c heater control vacuum harness retainer to the
side of the center distribution duct.
(6) Plug in the two halves of the a/c heater control
to HVAC housing vacuum harness connector.
(7) Connect the battery negative cable.
A/C HIGH PRESSURE SWITCH
DESCRIPTION
The a/c high pressure switch is located on the dis-
charge line near the compressor. The switch is
screwed onto a fitting that contains a Schrader-type
valve, which allows the switch to be serviced without
discharging the refrigerant system. The discharge
line fitting is equipped with an O-ring to seal the
switch connection.
OPERATION
The a/c high pressure switch is connected in series
electrically with the a/c low pressure switch between
ground and the Powertrain Control Module (PCM).
The switch contacts open and close causing the PCM
to turn the compressor clutch on and off. This pre-
vents compressor operation when the discharge line
pressure approaches high levels.
The a/c high pressure switch contacts are open
when the discharge line pressure rises above about
3100 to 3375 kPa (450 to 490 psi). The switch con-
tacts will close when the discharge line pressure
drops to about 1860 to 2275 kPa (270 to 330 psi).
When checking refrigerant system pressures with a
manifold gauge set, keep in mind that the indicated
pressures will be about 172 kpa (25 psi) below the
actual switch pressure values due to the pressure
drop that occurs in the refrigerant system between
the switch and the high pressure service port.
The a/c high pressure switch is a factory-calibrated
unit. The switch cannot be adjusted or repaired and,
if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - A/C HIGH
PRESSURE SWITCH
Before performing diagnosis of the a/c high pres-
sure switch, verify that the refrigerant system has
the correct refrigerant charge. (Refer to 24 - HEAT-
ING & AIR CONDITIONING - DIAGNOSIS AND
TESTING)
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the a/c high pressure switch wire har-
ness connector from the switch on the refrigerant
system fitting.
(3) On the four terminal high pressure switch,
check for continuity between terminals C and D. On
the two terminal switch, check for continuity
between both terminals of the a/c high pressure
switch. There should be continuity. If OK, test and
repair the A/C switch sense circuit as required. If not
OK, replace the faulty switch.
Fig. 19 A/C HEATER CONTROL REMOVE/INSTALL
1 - HEATED MIRROR WIRE HARNESS CONNECTOR
2 - WIRE HARNESS CONNECTOR
3 - SCREW
4 - HEATER-A/C CONTROL
24 - 20 CONTROLSBR/BE
A/C HEATER CONTROL (Continued)

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the a/c
high pressure switch, which is mounted to a fitting
on the discharge line between the compressor and
the condenser inlet.
(3) Unscrew the a/c high pressure switch from the
discharge line fitting.
(4) Remove the a/c high pressure switch from the
vehicle.
(5) Remove the O-ring seal from the discharge line
fitting and discard.
INSTALLATION
(1) Lubricate a new O-ring seal with clean refrig-
erant oil and install it on the discharge line fitting.
Use only the specified O-rings as they are made of a
special material for the R-134a system. Use only
refrigerant oil of the type recommended for the com-
pressor in the vehicle. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING/REFRIGERANT
OIL - DESCRIPTION)
(2) Install and tighten the high pressure cut-off
switch on the discharge line fitting. The switch
should be hand-tightened onto the discharge line fit-
ting.
(3) Plug the wire harness connector into the high
pressure cut-off switch.
(4) Connect the battery negative cable.
A/C LOW PRESSURE SWITCH
DESCRIPTION
The a/c low pressure switch is located on the top of
the accumulator. The switch is screwed onto an accu-
mulator fitting that contains a Schrader-type valve,
which allows the switch to be serviced without dis-
charging the refrigerant system. The accumulator fit-
ting is equipped with an O-ring to seal the switch
connection.
OPERATION
The a/c low pressure switch is connected in series
electrically with the a/c high pressure switch and the
a/c heater control, between ground and the Power-
train Control Module (PCM). The switch contacts
open and close causing the PCM to turn the compres-
sor clutch on and off. This regulates the refrigerant
system pressure and controls evaporator tempera-
ture. Controlling evaporator temperature prevents
condensate water on the evaporator fins from freez-
ing and obstructing air conditioning system air flow.
The a/c low pressure switch contacts are open
when the suction pressure is about 152-165 kPa(22-24 psi) or lower. The switch contacts will close
when the suction pressure rises to about 255-296 kPa
(37-43 psi) or above. Lower ambient temperatures,
below about -1É C (30É F), will also cause the switch
contacts to open. This is due to the pressure/temper-
ature relationship of the refrigerant in the system.
The a/c low pressure switch is a factory-calibrated
unit. It cannot be adjusted or repaired and, if faulty
or damaged, it must be replaced.
DIAGNOSIS AND TESTING - A/C LOW
PRESSURE SWITCH
Before performing diagnosis of the a/c low pressure
switch, be certain that the switch is properly
installed on the accumulator fitting. If the switch is
too loose it may not open the Schrader-type valve in
the accumulator fitting, which will prevent the
switch from correctly monitoring the refrigerant sys-
tem pressure. Also verify that the refrigerant system
has the correct refrigerant charge. (Refer to 24 -
HEATING & AIR CONDITIONING - DIAGNOSIS
AND TESTING - A/C PERFORMANCE)
Remember that lower ambient temperatures, below
about -1É C (30É F), during cold weather will open the
switch contacts and prevent compressor operation
due to the pressure/temperature relationship of the
refrigerant. For circuit descriptions and diagrams,
(Refer to Appropriate Wiring Information).
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the a/c low pressure switch wire har-
ness connector from the switch on the accumulator
fitting.
(3) Install a jumper wire between the two cavities
of the a/c low pressure switch wire harness connector.
(4) Connect a manifold gauge set to the refrigerant
system service ports. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM SERVICE
EQUIPMENT)
(5) Connect the battery negative cable.
(6) Place the a/c heater mode control switch knob
in any A/C position and start the engine.
(7) Check for continuity between the two terminals
of the low pressure cycling clutch switch. There
should be continuity with a suction pressure reading
of 296 kPa (43 psi) or above, and no continuity with a
suction pressure reading of 172 kPa (25 psi) or below.
If OK, test and repair the A/C switch sense circuit as
required. If not OK, replace the faulty switch.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
BR/BECONTROLS 24 - 21
A/C HIGH PRESSURE SWITCH (Continued)

(1) Disconnect and isolate the battery negative
cable.
(2) Remove the glove box from the instrument
panel. Refer to Glove Box in Instrument Panel Sys-
tem for the procedures.
(3) Reach through the glove box opening to access
and unplug the vacuum harness connector from the
recirculation door actuator (Fig. 27).
(4) Loosen the two nuts that secure the recircula-
tion door actuator to the mounting bracket on the
HVAC housing.
(5) Slide the two actuator mounting studs out of
the slots in the actuator mounting bracket.
(6) Pull the recirculation door actuator downward
far enough to access the clip that retains the actua-
tor link to the recirculation door lever.
(7) Unsnap the clip from the recirculation door
actuator link and disengage the link from the recir-
culation door lever.
(8) Remove the recirculation door actuator from
the HVAC housing.INSTALLATION
NOTE: When reinstalling the recirculation door
actuator, insert a screwdriver or another suitable
tool through the recirculation air intake grille to
prop the recirculation air door up in the open posi-
tion far enough to access the recirculation air door
lever through the instrument panel glove box open-
ing.
NOTE: Before installing the blend door actuator, be
certain that the blend door is not binding.
(1) Snap the clip on the recirculation door actuator
link to engage the link to the recirculation door lever.
(2) Slide the two actuator mounting studs into the
slots in the actuator mounting bracket.
(3) Install the two nuts that secure the recircula-
tion door actuator to the mounting bracket on the
HVAC housing. Tighten the mounting nuts until the
recirculation air door actuator is seated to the
mounting bracket.
(4) Plug in the vacuum harness connector to the
recirculation door actuator.
(5) Install the glove box in the instrument panel.
Refer to Glove Box in Instrument Panel System for
the procedures.
(6) Connect the battery negative cable.
VACUUM CHECK VALVE
DESCRIPTION
On models with a gasoline engine, a vacuum check
valve is installed in the accessory vacuum supply line
near the vacuum tap on the right side of the engine
intake manifold. On models with a diesel engine, a
vacuum check valve is installed on the engine vac-
uum pump. The vacuum check valve is designed to
allow vacuum to flow in only one direction through
the accessory vacuum supply circuits.
OPERATION
The use of a vacuum check valve helps to maintain
the system vacuum needed to retain the selected
HVAC mode and vehicle speed control settings. On
gasoline engine models, it prevents the engine from
bleeding down system vacuum through the intake
manifold during extended heavy engine load (low
engine vacuum) operation. On diesel engine models,
it prevents oil from contaminating the vacuum sup-
ply system by maintaining vacuum in the pump after
the engine is shut-off.
On gasoline engine models, a second vacuum check
valve is installed in the accessory vacuum supply line
at the tee fitting near the dash panel in the engine
Fig. 27 RECIRCULATION DOOR ACTUATOR
1 - DOOR SHAFT RETAINER
2 - RECIRCULATION DOOR
3 - ROD CLIP
4 - BLOWER MOTOR ELECTRICAL CONNECTOR
5 - RECIRCULATION DOOR ACTUATOR
6 - BLOWER MOTOR
7 - VACUUM LINE
24 - 28 CONTROLSBR/BE
RECIRCULATION DOOR ACTUATOR (Continued)

compartment. This check valve also helps to main-
tain the system vacuum needed to retain the selected
HVAC mode settings, but isolates the HVAC vacuum
circuit from the vehicle speed control vacuum circuit.
It prevents the vehicle speed control servo from
bleeding down the HVAC system vacuum during
extended heavy engine load operation.
The vacuum check valve cannot be repaired and, if
faulty or damaged, it must be replaced.
REMOVAL
(1) On models with a gasoline engine, unplug the
vacuum supply line connector at the vacuum check
valve (Fig. 28). On models with a diesel engine,
remove the clamp from the vacuum supply line con-
nector and unplug the connector from the vacuum
check valve (Fig. 29).
(2) On models with a gasoline engine, note the ori-
entation of the check valve in the vacuum supply line
for correct reinstallation.
(3) On models with a gasoline engine, unplug the
remaining line on the vacuum check valve from the
vacuum supply line fitting. On models with a diesel
engine, unscrew the check valve and nipple unit from
the engine vacuum pump.
INSTALLATION
(1) On models with a gasoline engine, plug in the
vacuum check valve to the vacuum line fittings, not-ing the proper orientation of the check valve in the
line. On models with a diesel engine, screw the check
valve and nipple unit into the engine vacuum pump.
Tighten the check valve and nipple unit to 24 N´m
(18 ft. lbs.).
(2) On models with a diesel engine, plug in the
connector to the vacuum check valve and install the
clamp from the vacuum supply line connector.
VACUUM RESERVOIR
DESCRIPTION
Models equipped with a gasoline engine have a
vacuum reservoir. The vacuum reservoir is mounted
in the passenger side cowl plenum area, under the
cowl plenum cover/grille panel. The cowl plenum cov-
er/grille panel must be removed from the vehicle to
access the vacuum reservoir for service.
OPERATION
Engine vacuum is stored in the vacuum reservoir.
The stored vacuum is used to operate the vacuum-
controlled vehicle accessories during periods of low
engine vacuum such as when the vehicle is climbing
a steep grade, or under other high engine load oper-
ating conditions.
The vacuum reservoir cannot be repaired and, if
faulty or damaged, it must be replaced.
Fig. 28 VACUUM CHECK VALVES - GASOLINE
ENGINE
1 - INTAKE MANIFOLD VACUUM TAP
2 - VACUUM CHECK VALVES
Fig. 29 VACUUM CHECK VALVE - DIESEL ENGINE
1 - VACUUM CHECK VALVE
2 - VACUUM SUPPLY LINE
BR/BECONTROLS 24 - 29
VACUUM CHECK VALVE (Continued)

TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(2) Remove the secondary clip from the spring-lock
coupler.
(3) Fit the proper size A/C line disconnect tool
(Special Tool Kit 7193) over the spring-lock coupler
cage (Fig. 2).
(4) Close the two halves of the A/C line disconnect
tool around the spring-lock coupler.
(5) Push the A/C line disconnect tool into the open
side of the coupler cage to expand the garter spring.
Once the garter spring is expanded and while still
pushing the disconnect tool into the open side of the
coupler cage, pull on the refrigerant line attached to
the female half of the coupler fitting until the flange
on the female fitting is separated from the garter
spring and cage on the male fitting within the dis-
connect tool.
INSTALLATION
(1) Check to ensure that the garter spring is
located within the cage of the male coupler fitting,
and that the garter spring is not damaged.
(a) If the garter spring is missing, install a new
spring by pushing it into the coupler cage opening.
(b) If the garter spring is damaged, remove it
from the coupler cage with a small wire hook (DO
NOT use a screwdriver) and install a new garter
spring.
(2) Clean any dirt or foreign material from both
halves of the coupler fitting.(3) Install new O-rings on the male half of the cou-
pler fitting.
CAUTION: Use only the specified O-rings as they
are made of a special material for the R-134a sys-
tem. The use of any other O-rings may allow the
connection to leak intermittently during vehicle
operation.
(4) Lubricate the male fitting and O-rings, and the
inside of the female fitting with clean R-134a refrig-
erant oil. Use only refrigerant oil of the type recom-
mended for the compressor in the vehicle.
(5) Fit the female half of the coupler fitting over
the male half of the fitting.
(6) Push together firmly on the two halves of the
coupler fitting until the garter spring in the cage on
the male half of the fitting snaps over the flanged
end on the female half of the fitting.
(7) Ensure that the spring-lock coupler is fully
engaged by trying to separate the two coupler halves.
This is done by pulling the refrigerant lines on either
side of the coupler away from each other.
(8) Reinstall the secondary clip over the spring-
lock coupler cage.
STANDARD PROCEDURE - REFRIGERANT
SYSTEM SERVICE EQUIPMENT
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
When servicing the air conditioning system, a
R-134a refrigerant recovery/recycling/charging sta-
tion that meets SAE Standard J2210 must be used.
Contact an automotive service equipment supplier for
refrigerant recovery/recycling/charging equipment.
Refer to the operating instructions supplied by the
equipment manufacturer for proper care and use of
this equipment.
A manifold gauge set may be needed with some
recovery/recycling/charging equipment (Fig. 3). The
service hoses on the gauge set being used should
have manual (turn wheel), or automatic back-flow
valves at the service port connector ends. This will
prevent refrigerant from being released into the
atmosphere.
MANIFOLD GAUGE SET CONNECTIONS
CAUTION: Do not use an R-12 manifold gauge set
on an R-134a system. The refrigerants are not com-
patible and system damage will result.
Fig. 2 REFRIGERANT LINE SPRING-LOCK
COUPLER DISCONNECT
24 - 44 PLUMBINGBR/BE
PLUMBING (Continued)

LOW PRESSURE GAUGE HOSE The low pressure
hose (Blue with Black stripe) attaches to the suction
service port. This port is located on the suction line
between the accumulator outlet and the compressor.
HIGH PRESSURE GAUGE HOSE The high pres-
sure hose (Red with Black stripe) attaches to the dis-
charge service port. This port is located on the
discharge line between the compressor and the con-
denser inlet.
RECOVERY/RECYCLING/EVACUATION/CHARG-
ING HOSE The center manifold hose (Yellow, or
White, with Black stripe) is used to recover, evacu-
ate, and charge the refrigerant system. When the low
or high pressure valves on the manifold gauge set
are opened, the refrigerant in the system will escape
through this hose.
STANDARD PROCEDURE - REFRIGERANT
RECOVERY
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to recover the refrigerant from an R-134a refrig-
erant system. Refer to the operating instructions sup-
plied by the equipment manufacturer for the proper
care and use of this equipment.
STANDARD PROCEDURE - REFRIGERANT
SYSTEM EVACUATE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
If the refrigerant system has been open to the
atmosphere, it must be evacuated before the system
can be charged. If moisture and air enters the system
and becomes mixed with the refrigerant, the com-
pressor head pressure will rise above acceptable
operating levels. This will reduce the performance of
the air conditioner and damage the compressor.
Evacuating the refrigerant system will remove the
air and boil the moisture out of the system at near
room temperature. To evacuate the refrigerant sys-
tem, use the following procedure:
(1) Connect a R-134a refrigerant recovery/recy-
cling/charging station that meets SAE Standard
J2210 and a manifold gauge set to the refrigerant
system of the vehicle.
(2) Open the low and high side valves and start
the charging station vacuum pump. When the suc-
tion gauge reads 88 kPa (26 in. Hg.) vacuum or
greater, close all of the valves and turn off the vac-
uum pump.
(a) If the refrigerant system fails to reach the
specified vacuum, the system has a leak that must
be corrected. (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - DIAGNOSIS AND
TESTING - REFRIGERANT SYSTEM LEAKS)
(b) If the refrigerant system maintains the spec-
ified vacuum for five minutes, restart the vacuum
pump, open the suction and discharge valves and
evacuate the system for an additional ten minutes.
(3) Close all of the valves, and turn off the charg-
ing station vacuum pump.
(4) The refrigerant system is now ready to be
charged with R-134a refrigerant. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
Fig. 3 MANIFOLD GAUGE SET - TYPICAL
1 - HIGH PRESSURE GAUGE
2 - VALVE
3 - VACUUM/REFRIGERANT HOSE (YELLOW W/ BLACK
STRIPE)
4 - HIGH PRESSURE HOSE (RED W/ BLACK STRIPE)
5 - LOW PRESSURE HOSE (BLUE W/ BLACK STRIPE)
6 - VALVE
7 - LOW PRESSURE GAUGE
BR/BEPLUMBING 24 - 45
PLUMBING (Continued)

STANDARD PROCEDURE - REFRIGERANT
SYSTEM CHARGE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
After the refrigerant system has been tested for
leaks and evacuated, a refrigerant charge can be
injected into the system. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - SPECIFICA-
TIONS - CHARGE CAPACITY)
A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to charge the refrigerant system with R-134a
refrigerant. Refer to the operating instructions sup-
plied by the equipment manufacturer for proper care
and use of this equipment.
SPECIFICATIONS
SPECIFICATIONS
The R-134a refrigerant system charge capacity for
this vehicle is: 0.907 kilograms (32 ounces).
A/C COMPRESSOR
DESCRIPTION - A/C COMPRESSOR
The air conditioning system uses a Sanden
SD7H15 seven cylinder, reciprocating wobble plate-
type compressor on all models. This compressor has a
fixed displacement of 150 cubic centimeters (9.375
cubic inches), and has both the suction and discharge
ports located on the cylinder head. A label identifying
the use of R-134a refrigerant is located on the com-
pressor.
DESCRIPTION - HIGH PRESSURE RELIEF
VALVE
A high pressure relief valve is located on the com-
pressor cylinder head, which is at the rear of the
compressor. This mechanical valve is designed to
vent refrigerant from the system to protect against
damage to the compressor and other system compo-
nents, caused by condenser air flow restriction or an
overcharge of refrigerant.
OPERATION - A/C COMPRESSOR
The compressor is driven by the engine through an
electric clutch, drive pulley and belt arrangement.
The compressor is lubricated by refrigerant oil that iscirculated throughout the refrigerant system with the
refrigerant.
The compressor draws in low-pressure refrigerant
vapor from the evaporator through its suction port. It
then compresses the refrigerant into a high-pressure,
high-temperature refrigerant vapor, which is then
pumped to the condenser through the compressor dis-
charge port.
The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley and clutch
coil are available for service.
OPERATION - HIGH PRESSURE RELIEF VALVE
The high pressure relief valve vents the system
when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes with
a minimum discharge pressure of 2756 kPa (400 psi)
is reached.
The high pressure relief valve vents only enough
refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean the valve is faulty.
The high pressure relief valve is a factory-cali-
brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The valve is only serviced as a part of the
compressor assembly.
DIAGNOSIS AND TESTING - A/C COMPRESSOR
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.
Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressor
noise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen-
gaged. Check the serpentine drive belt condition and
tension as described in Cooling before beginning this
procedure.
(1) Select a quiet area for testing. Duplicate the
complaint conditions as much as possible. Switch the
compressor on and off several times to clearly iden-
tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
24 - 46 PLUMBINGBR/BE
PLUMBING (Continued)

the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet-
ter localize the source of the noise.
(2) Loosen all of the compressor mounting hard-
ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and pulley are properly aligned and have
the correct air gap. (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH - INSTALLATION)
(3) To duplicate a high-ambient temperature condi-
tion (high head pressure), restrict the air flow
through the condenser. Install a manifold gauge set
to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).
(4) Check the refrigerant system plumbing for
incorrect routing, rubbing or interference, which can
cause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAU-
TION)
(5) If the noise is from opening and closing of the
high pressure relief valve, recover, evacuate, and
recharge the refrigerant system. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT RECOVERY)
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - REFRIG-
ERANT SYSTEM EVACUATE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE) If the high pressure relief valve still
does not seat properly, replace the compressor.
(6) If the noise is from liquid slugging on the suc-
tion line, replace the accumulator. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/AC-
CUMULATOR - REMOVAL) Check the refrigerant oil
level and the refrigerant system charge. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING/
REFRIGERANT OIL - STANDARD PROCEDURE -
REFRIGERANT OIL LEVEL) (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - SPECI-
FICATIONS - CHARGE CAPACITY) If the liquid
slugging condition continues following accumulator
replacement, replace the compressor.
(7) If the noise continues, replace the compressor
and repeat Step 1.
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis-
charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt. Refer to
Cooling for the procedures.
(4) Unplug the compressor clutch coil wire harness
connector.
(5) Remove the bolt that secures the refrigerant
line manifold to the compressor. Install plugs in, or
tape over all of the opened refrigerant line fittings.
(6) Remove the four bolts that secure the compres-
sor to the mounting bracket (Fig. 4) or (Fig. 5).
(7) Remove the a/c compressor from the mounting
bracket.
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)(Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTION - REFRIGERANT HOSES/LINES/TUBES
PRECAUTIONS)
NOTE: If a replacement compressor is being
installed, be certain to check the refrigerant oil
level. (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT OIL - STANDARD PRO-
CEDURE) Use only refrigerant oil of the type
recommended for the compressor in the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/REFRIGERANT OIL - DESCRIPTION)
(1) Install the compressor to the mounting bracket.
Tighten the four mounting bolts to 24 N´m (210 in.
lbs.).
(2) Remove the tape or plugs from all of the
opened refrigerant line fittings. Install the suction
and discharge line manifold to the compressor. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING/A/C SUCTION AND DISCHARGE LINE -
INSTALLATION)
BR/BEPLUMBING 24 - 47
A/C COMPRESSOR (Continued)

(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P0206 (M) Injector #6 Control Circuit Injector #6 output driver stage does not respond properly
to the control signal.
P0207 (M) Injector #7 Control Circuit Injector #7 output driver stage does not respond properly
to the control signal.
P0208 (M) Injector #8 Control Circuit Injector #8 output driver stage does not respond properly
to the control signal.
P0209 (M) Injector #9 Control Circuit Injector #9 output driver stage does not respond properly
to the control signal.
P0210 (M) Injector #10 Control Circuit Injector #10 output driver stage does not respond properly
to the control signal.
P0215 Fuel Injection Pump Control Circuit Failure in fuel pump relay control circuit.
P0216 (M) Fuel Injection Pump Timing Failure High fuel supply restriction, low fuel pressure or possible
wrong or incorrectly installed pump keyway.
P0217 Decreased Engine Performance Due
To Engine Overheat ConditionEngine overheating. ECM will derate engine performance.
P0219 Crankshaft Position Sensor
Overspeed SignalEngine has exceeded rpm limits.
P0222 (M) Idle Validation Signals Both Low Problem detected with idle validation circuits within APPS.
P0223 (M) Idle Validation Signals Both High
(Above 5 Volts)Problem detected with idle validation circuits within APPS.
P0230 Transfer Pump (Lift Pump) Circuit
Out of RangeProblem detected in fuel transfer pump circuits.
P0232 Fuel Shutoff Signal Voltage Too High Fuel shut-off signal voltage too high from ECM to fuel
injection pump.
P0234 (M) Turbo Boost Limit Exceeded Problem detected in turbocharger wastegate.
P0236 (M) Map Sensor Too High Too Long Problem detected in turbocharger wastegate.
P0237 (M) Map Sensor Voltage Too Low MAP sensor voltage input below the minimum acceptable
voltage.
P0238 (M) Map Sensor Voltage Too High MAP sensor voltage input above the maximum
acceptable voltage.
P0251 (M) Fuel Inj. Pump Mech. Failure Fuel
Valve Feedback CircuitProblem sensed with fuel circuit internal to fuel injection
pump.
P0253 (M) Fuel Injection Pump Fuel Valve
Open CircuitProblem sensed with fuel circuit internal to fuel injection
pump.
P0254 Fuel Injection Pump Fuel Valve
Current Too HighProblem caused by internal fuel injection pump failure.
P0300 (M) Multiple Cylinder Mis-fire Misfire detected in multiple cylinders.
P0301 (M) CYLINDER #1 MISFIRE Misfire detected in cylinder #1.
P0302 (M) CYLINDER #2 MISFIRE Misfire detected in cylinder #2.
P0303 (M) CYLINDER #3 MISFIRE Misfire detected in cylinder #3.
P0304 (M) CYLINDER #4 MISFIRE Misfire detected in cylinder #4.
P0305 (M) CYLINDER #5 MISFIRE Misfire detected in cylinder #5.
BR/BEEMISSIONS CONTROL 25 - 5
EMISSIONS CONTROL (Continued)