1993 CHEVROLET PLYMOUTH ACCLAIM air conditioning

within a range of 12.9 to 15.0 volts. Refer to Group
8A for charging system information.
AUTO SHUTDOWN (ASD) RELAY AND FUEL PUMP
RELAYÐPCM OUTPUT
The PCM operates the auto shutdown (ASD) relay
and fuel pump relay through one ground path. The
PCM operates the relays by switching the ground
path on and off. Both relays turn on and off at the
same time. The ASD relay connects battery voltage to the fuel
injector and ignition coil. The fuel pump relay con-
nects battery voltage to the fuel pump and oxygen
sensor heating element. The PCM turns the ground path off when the igni-
tion switch is in the Off position. Both relays are off.
When the ignition switch is in the On or Crank po-
sition, the PCM monitors the crankshaft position
sensor and camshaft position sensor signals to deter-
mine engine speed and ignition timing (coil dwell). If
the PCM does not receive the crankshaft position
sensor and camshaft position sensor signals when the
ignition switch is in the Run position, it de-energizes
both relays. When the relays are de-energized, bat-
tery voltage is not supplied to the fuel injector, igni-
tion coil, fuel pump and oxygen sensor heating
element. The ASD relay and fuel pump relay are located in
the power distribution center (Fig. 14).
IDLE AIR CONTROL MOTORÐPCM OUTPUT
The idle air control motor is mounted on the throt-
tle body. The PCM operates the idle air control motor
(Fig. 13). The PCM adjusts engine idle speed through
the idle air control motor to compensate for engine
load or ambient conditions. The throttle body has an air bypass passage that
provides air for the engine at idle (the throttle blade is closed). The idle air control motor pintle protrudes
into the air bypass passage and regulates air flow
through it. The PCM adjusts engine idle speed by moving the
idle air control motor pintle in and out of the bypass
passage. The adjustments are based on inputs the
PCM receives. The inputs are from the throttle posi-
tion sensor, crankshaft position sensor, coolant tem-
perature sensor, and various switch operations
(brake, park/neutral, air conditioning). Deceleration
die out is also prevented by increasing airflow when
the throttle is closed quickly after a driving (speed)
condition.
CANISTER PURGE SOLENOIDÐPCM OUTPUT
Vacuum for the Evaporative Canister is controlled
by the Canister Purge Solenoid (Fig. 15). The sole-
noid is controlled by the PCM.
The PCM operates the solenoid by switching the
ground circuit on and off based on engine operating
conditions. When energized, the solenoid prevents
vacuum from reaching the evaporative canister.
When not energized the solenoid allows vacuum to
flow to the canister. The PCM removes the ground to the solenoid when
the engine reaches a specified temperature and the
time delay interval has occurred. When the solenoid
is de-energized, vacuum flows to the canister purge
valve. Vapors are purged from the canister and flow
to the throttle body. The purge solenoid will also be energized during
certain idle conditions, in order to update the fuel de-
livery calibration.
MALFUNCTION INDICATOR LAMP (CHECK ENGINE
LAMP)ÐPCM OUTPUT
The malfunction indicator lamp (instrument panel
Check Engine Lamp) comes on each time the ignition
key is turned ON and stays on for 3 seconds as a
bulb test. The malfunction indicator lamp warns the
Fig. 14 Relay Identification
Fig. 15 Canister Purge Solenoid
Ä FUEL SYSTEMS 14 - 151

WIDE OPEN THROTTLE MODE This is an OPEN LOOP mode. During wide-open-
throttle operation, the following inputs are received
by the PCM:
² battery voltage
² engine coolant temperature
² manifold absolute pressure
² engine speed
² throttle position
When the PCM senses wide open throttle condition
through the throttle position sensor (TPS) it will:
² De-energize the air conditioning relay. This dis-
ables the air conditioning system.
² Provide a ground for the electrical EGR transducer
(EET) solenoid. When the PCM grounds the solenoid,
the EGR system stops operating. The exhaust gas oxygen content input is not ac-
cepted by the PCM during wide open throttle opera-
tion. The PCM will adjust injector pulse width to
supply a predetermined amount of additional fuel.
IGNITION SWITCH OFF MODE When the ignition switch is turned to the OFF po-
sition, the following occurs:
² All outputs are turned off.
² No inputs are monitored.
² The PCM shuts down.
THROTTLE BODY
The throttle body assembly is located on the left
side of the intake manifold plenum (Fig. 19). The
throttle body houses the throttle position sensor and
the idle air control motor. Air flow through the throt- tle body is controlled by a cable operated throttle
blade located in the base of the throttle body.
FUEL SUPPLY CIRCUIT
Fuel is pumped to the fuel rail by an electrical
pump in the fuel tank. The pump inlet is fitted with
a strainer to prevent water and other contaminants
from entering the fuel supply circuit. Fuel pressure is controlled to a preset level above
intake manifold pressure by a pressure regulator.
The regulator is mounted on the fuel rail. The regu-
lator uses intake manifold pressure as a reference.
FUEL INJECTORS AND FUEL RAIL ASSEMBLY
Six fuel injectors are retained in the fuel rail by
lock rings (Fig. 20). The rail and injector assembly is
installed in position with the injectors inserted in re-
cessed holes in the intake manifold.
Fig. 19 Throttle Body
Fig. 20 Fuel Rail Assembly
Ä FUEL SYSTEMS 14 - 155

(18) Lower vehicle.
(19) Install the serpentine drive belt. Refer to (Fig.
10) for correct serpentine belt routing. See Cooling,
Group 7 for detailed installation procedure.
CAUTION: Do not use automatic transmission fluid
in power steering system. Only use Mopar T, Power
Steering Fluid, or equivalent.
(20) Fill power steering pump reservoir to correct
fluid level. (21) Connect the negative battery cable on the
negative battery post. (22) Start engine and turn steering wheel several
times from stop to stop to bleed air from fluid in sys-
tem. Stop engine, check fluid level, and inspect sys-
tem for leaks. See Checking Fluid Level.
TURBO III
REMOVE
(1) Disconnect the battery (-) negative cable from
the battery and isolate cable. (2) Raise vehicle See Hoisting, Group 0. Put oil
drain pan under vehicle to catch power steering
fluid. (3) Remove the right front underhood splash shield
for access to the serpentine belt tensioner. (4) Release the tension on the serpentine drive belt
tensioner and remove drive belt from power steering
pump pulley (Fig. 20). Drive belt does not have to be
fully removed from engine.
(5) Remove the power steering fluid return hose at
the steering gear metal tube. Let power steering
fluid drain from the hose and power steering pump
into drain pan. (6) Remove the high pressure fluid line banjo bolt
fitting from the power steering pump. Remove high
pressure power steering fluid line from the power
steering pump. (7) Remove the lower power steering pump to
bracket mounting nut and fluid hose routing clip. Re-
move the 2 bolts and the stud attaching the power
steering pump to its mounting bracket (Fig. 21).
(8) Lower vehicle.
(9) Remove the wiring harness electrical connector
from the H-valve on the air conditioning fluid lines. (10) Remove the power steering pump from the ve-
hicle out through the area between the cylinder head
and the dash panel (Fig. 22).
(11) Transfer the required components from the
failed power steering pump to the replacement power
steering pump. See the appropriate area of this ser-
vice manual section for the component replacement
procedures.
Fig. 20 Turbo III Accessory Drive Belt Routing
Fig. 21 Power Steering Pump Mounting
Fig. 22 Power Steering Pump Removal From Vehicle
Ä STEERING 19 - 19

INSTALL (1) Install the power steering pump back into the
vehicle in the reverse order of removal, between cyl-
inder head and dash panel (Fig. 20). (2) Install the wiring harness connector back on
the H-valve located on the air conditioning fluid
lines (Fig. 20). (3) Raise vehicle See Hoisting, Group 0.
(4) Install the power steering pump on its mount-
ing bracket, and the hose locator bracket. Install the
bolt/stud and 2 bolts attaching the power steering
pump to its mounting bracket, and the bolts attach-
ing the hose locator bracket (Fig. 19). Torque all fas-
teners to 31 N Im (280 in. lbs.).
(5) Install the power steering fluid pressure hose,
banjo bolt and seal washer onto power steering pump
(Fig. 4). Pressure hose is to be installed so it is
routed to the left of the hose locator bracket (Fig.
19). Torque the banjo bolt to 31 N Im (275 in. lbs.).
Inspect the O-rings on the banjo bolt to ensure
they are not damaged and located correctly. (6) Install the low pressure fluid return hose from
the power steering pump back on the steel tube on
the steering gear (Fig. 4). Install hose clamp, be sure
the hose clamp is installed past the retaining bead
the steel tube. Install the hose routing clip on the
power steering pump bolt/stud, install clip retaining
nut and tighten. (7) Install the serpentine accessory drive belt (Fig.
18). Be sure the belt is correctly installed and
aligned on all pulleys before starting engine. (8) Install the right front underhood splash shield.
CAUTION: Do not use automatic transmission fluid
in power steering system. Only use Mopar T, Power
Steering Fluid, or equivalent.
(9) Fill power steering pump reservoir to correct
fluid level. (10) Connect the negative battery cable on the
negative battery post. (11) Start engine and turn steering wheel several
times from stop to stop to bleed air from fluid in sys-
tem. Stop engine, check fluid level, and inspect sys-
tem for leaks. See Checking Fluid Level.
POWER STEERING PUMP PULLEY SERVICE
SAGINAW VANE SUBMERGED PUMP
REMOVE
(1) Remove the pulley with Puller C-4333 (C-4068)
(Fig. 1).
CAUTION: Do not hammer on power steering pump
pulley. This will damage the pulley and the power
steering pump. (2) Replace pulley if bent, cracked, or loose.
INSTALLATION
(1) Install the pulley with Installer C-4063 (Fig.2).
Do not use the tool adapters.
(2) Ensure that the tool and the pulley remain
aligned with the pump shaft. Prevent the pulley from
being cocked on the shaft. (3) Force pulley flush with the end of the shaft.
Fig. 1 Pulley Removal (Typical)
Fig. 2 Pulley Installation (Typical)
19 - 20 STEERING Ä

HEATING AND AIR CONDITIONING
CONTENTS
page page
AUTOMATIC TEMPERATURE CONTROL (ATC) .............................. 66
COMPONENT SERVICE PROCEDURES ...... 47
FIXED DISPLACEMENT COMPRESSORÐ MODEL 10PA17 ...................... 24
FIXED DISPLACEMENT COMPRESSORÐ MODEL SD709P ...................... 38 FIXED DISPLACEMENT COMPRESSORÐ
MODEL TR105 ....................... 32
GENERAL INFORMATION .................. 1
HEATER AND A/C PERFORMANCE TESTS .... 6
REFRIGERANT SERVICE PROCEDURES ...... 8
VACUUM CONTROL SYSTEM DIAGNOSIS .... 4
VARIABLE DISPLACEMENT COMPRESSORÐ MODEL 6C17 ......................... 13
GENERAL INFORMATION INDEX
page page
A/C System Identification ................... 1
Cooling System Precautions ................. 3
Description and Operation ................... 1
Engine Cooling System Requirements .......... 2 Handling Tubing and Fittings
................. 3
Safety Precautions and Warnings ............. 3
Side Window Demisters .................... 2
System Airflow ........................... 1
A/C SYSTEM IDENTIFICATION
The terms Fixed Displacement Compressor and
Variable Displacement Compressor will be used to
describe the two types of A/C systems used through-
out this Group. Refer to (Figs. 1, 2, 3 and 4). The Variable Displacement Compressor can be
identified by the location of the high pressure line. It
is mounted to the end of the compressor case (Fig. 4).
DESCRIPTION AND OPERATION
Both the heater and the heater/air conditioning
systems share many of the same functioning compo-
nents. This Group will deal with both systems to-
gether when component function is common, and
separately when they are not. For proper operation of the instrument panel con-
trols, refer to the Owner's Manual provided with the
vehicle. All vehicles are equipped with a common A/C-heat-
er unit housing assembly. On heater only systems,
the evaporator and recirculating air door are omitted
(Fig. 5).
SYSTEM AIRFLOW
The system pulls outside (ambient) air through the
cowl opening at the base of the windshield. Then it
goes into the plenum chamber above the A/C-heater unit housing. On air conditioned vehicles, the air
passes through the evaporator. Air flow can be di-
rected either through or around the heater core. This
Fig. 1 Fixed Displacement CompressorÐModel 10PA17
Ä HEATING AND AIR CONDITIONING 24 - 1

is done by adjusting the blend-air door with the
TEMP control on the instrument panel. The air flow
can then be directed from the PANEL, BI-LEVEL
(panel and floor), and FLOOR-DEFROST outlets. Air
flow velocity can be adjusted with the blower speed
selector switch on the instrument panel (Fig. 6). On air conditioned vehicles, ambient air intake can
be shut off by closing the recirculating air door. This
will recirculate the air that is already inside the ve-
hicle. This is done by moving the TEMP control into
the RECIRC position. Depressing the DEFROST or
A/C button will engage the compressor. This will send refrigerant through the evaporator, and will re-
move heat and humidity from the air before it is di-
rected through or around the heater core.
SIDE WINDOW DEMISTERS
The side window demisters direct air from the
heater assembly. The outlets are located on the top
outboard corners of the instrument panel. The De-
misters operate when the A/C control mode selector
is on FLOOR or DEFROST setting.
ENGINE COOLING SYSTEM REQUIREMENTS
To maintain the performance level of the heating/
air conditioning system, the engine cooling system
must be prepared as shown in this manual. The use of a bug screen is not recommended. Any
obstructions in front of the radiator or condenser can
reduce the performance of the A/C or engine cooling
system.
Fig. 2 Fixed Displacement CompressorÐModel TR105
Fig. 3 Fixed Displacement CompressorÐModelSD709P
Fig. 4 Variable Displacement CompressorÐModel 6C17
Fig. 5 Common Blend-Air Heater A/C System
24 - 2 HEATING AND AIR CONDITIONING Ä

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 RE-
FRIGERANT 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 (R-12) REFRIGER-
ANT AT AVERAGE TEMPERATURE AND ALTITUDE
IS EXTREMELY HIGH. AS A RESULT, ANYTHING
THAT COMES IN CONTACT WITH THE REFRIGER-
ANT WILL FREEZE. ALWAYS PROTECT SKIN OR
DELICATE OBJECTS FROM DIRECT CONTACT
WITH REFRIGERANT.
CAUTION: Liquid refrigerant is corrosive to metal
surfaces. Follow the operating instructions supplied
with equipment being used.
COOLING SYSTEM PRECAUTIONS
WARNING: ANTIFREEZE IS AN ETHYLENE GLYCOL
BASE COOLANT AND IS HARMFUL IF SWAL-
LOWED OR INHALED. IF SWALLOWED, DRINK
TWO GLASSES OF WATER AND INDUCE VOMIT-
ING. IF INHALED, MOVE TO FRESH AIR AREA.
SEEK MEDICAL ATTENTION IMMEDIATELY. DO NOT STORE IN OPEN OR UNMARKED CON-
TAINERS. WASH SKIN AND CLOTHING THOROUGHLY AF-
TER COMING IN CONTACT WITH ETHYLENE GLY-
COL. 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.
The engine cooling system is designed to develop
internal pressure of 97 to 123 kPa (14 to 18 psi). Al-
low the vehicle 15 minutes (or until a safe tempera-
ture and pressure are attained) before opening the
cooling system. Refer to Group 7, Cooling System.
HANDLING TUBING AND FITTINGS
Kinks in the refrigerant tubing or sharp bends in
the refrigerant hose lines will greatly reduce the ca-
pacity of the entire system. High pressures are pro-
duced in the system when it is operating. Extreme
care must be exercised to make sure that all connec-
tions are pressure tight. Dirt and moisture can enter
the system when it is opened for repair or replace-
ment of lines or components. The refrigerant oil will
absorb moisture readily out of the air. This moisture
will convert into acids within a closed system. The following precautions must be observed:
The system must be completely empty before open-
ing any fitting or connection in the refrigeration sys-
tem. Open fittings with caution even after the
system has been emptied. If any pressure is noticed
as a fitting is loosened, allow trapped pressure to
bleed off very slowly. A good rule for the flexible hose lines is to keep the
radius of all bends at least 10 times the diameter of
the hose. Sharper bends will reduce the flow of re-
frigerant. The flexible hose lines should be routed so
they are at least 3 inches (80 mm) from the exhaust
manifold. Inspect all flexible hose lines to make sure
they are in good condition and properly routed. Unified plumbing connections with aluminum gas-
kets cannot be serviced with O-rings. These gaskets
are not reusable and do not require lubrication be-
fore installing. The use of correct wrenches when making connec-
tions is very important. Improper wrenches or im-
proper use of wrenches can damage the fittings. The A/C system will remain chemical stabile as
long as pure-moisture-free R-12 and refrigerant oil is
used. Abnormal amounts of dirt, moisture or air can
upset the chemical stability. This condition could
cause operational troubles or even serious damage if
present in more than very small quantities. When it is necessary to open the refrigeration sys-
tem, have everything needed to service the system
ready. The system should not be left open any longer
than necessary. Cap or plug all lines and fittings as
soon as they are opened to prevent the entrance or
dirt and moisture. All lines and components in parts
stock should be capped or sealed until they are ready
to be used. All tools, including the refrigerant dispensing man-
ifold, the manifold gauge set, and test hoses should
be kept clean and dry.
Fig. 6 Heater only or HeaterÐA/C Controls
Ä HEATING AND AIR CONDITIONING 24 - 3

VACUUM CONTROL SYSTEM DIAGNOSIS
GENERAL INFORMATION
Use an adjustable Vacuum Test Gauge (C-3707)
and a suitable vacuum pump to test heater A/C con-
trol vacuum. With a finger placed over the end of
test hose (Fig. 1), calibrate vacuum control valve on
the test gauge to obtain -27 kPa (8 in. Hg.). Release
and block the end of the test hose several times to
verify vacuum setting.
VACUUM TESTING THE ONE-WAY CHECK VALVE
(1) In the engine compartment, disconnect the
Heater-A/C vacuum supply (black) hose. This hose
passes through an opening in the dash panel used for
the air conditioning expansion valve. (2) Remove the vacuum check valve. This valve is
located on the (black) vacuum supply hose at the
brake power booster. (3) Connect test vacuum supply hose to the heater
side of the valve. In this direction the gauge should
return to calibrated setting. If valve leaks vacuum in
this direction, valve replacement is necessary. (4) Connect test vacuum supply hose to the engine
vacuum side of the valve. Vacuum should flow
through valve.
VACUUM TESTING THE HEATER-A/C CONTROLS
(1) Connect the test vacuum prod to the vehicles
(black) vacuum supply hose. Position vacuum test
gauge so it can be viewed from the passenger com-
partment. (2) Position the heater A/C control mode selector to
DEFROST, FLOOR, BI-LEVEL, PANEL, and RE-
CIRC (with A/C). Pause after each selection. The test
gauge should return to the calibrated setting of -27
kPa (8 in. Hg.) after each selection is made. If the
gauge cannot achieve the calibrated setting, a vac-
uum circuit or component has a leak.
LOCATING VACUUM LEAKS
To locate a vacuum leak, disconnect 7-way vacuum
connector behind the instrument panel at the heater
A/C control. For removal and installation of heater
A/C control panel, refer to the Switch and Panel
Component Service section of Group 8E, Instrument
Panel. Connect the calibrated vacuum hose prod (Fig.
4) to each port in the vacuum harness connector (Fig.
2). The brown, bi-level, vacuum circuit has a metal
fiber restrictive device located in the line. More reac-
tion time is required for the test gauge to return to
calibrated setting. After each connection is made, the
test gauge should return to calibrated setting. If all
circuits function properly, replace control mode vac-
uum switch. If not, determine the color of the vac-
uum circuit that is leaking. To determine vacuum
line colors, refer to the Vacuum Circuits-Heater or
Heater A/C Control chart in this section. Disconnect
the vacuum actuator at the other end of the circuit.
(Instrument panel removal may be necessary to gain
access to some components). Block the end of the dis-
connected vacuum line. The test gauge should return
to calibrated setting. If not, that circuit has a leak
and must be repaired or replaced. If test gauge re-
turns to calibrated setting, the vacuum actuator
must be replaced.
Fig. 1 Adjust Vacuum Test Bleed Valve
Fig. 2 Vacuum Circuit Test
24 - 4 HEATING AND AIR CONDITIONING Ä