(3) Install steering column lower shroud.
(4) Install knee bolster (Fig. 274).
(5) Install instrument panel lower silencer (Fig.
275).
(6) Connect battery negative cable.
(7) Verify proper shift interlock system operation.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 31TH/SHIFT INTERLOCK SOLENOID -
OPERATION)
SOLENOID/PRESSURE
SWITCH ASSY
DESCRIPTION
The Solenoid/Pressure Switch Assembly (Fig. 276)
is external to the transaxle and mounted to the transaxle case. The assembly consists of four sole-
noids that control hydraulic pressure to the LR/CC,
2/4, OD, and UD friction elements. The reverse
clutch is controlled by line pressure from the manual
valve in the valve body. The solenoids are contained
within the Solenoid/Pressure Switch Assembly, and
can only be serviced by replacing the assembly.
The solenoid assembly also contains pressure
switches that monitor and send hydraulic circuit
information to the PCM/TCM. Likewise, the pressure
switches can only be service by replacing the assem-
bly.
OPERATION
SOLENOIDS
The solenoids receive electrical power from the
Transmission Control Relay through a single wire.
The PCM/TCM energizes or operates the solenoids
individually by grounding the return wire of the sole-
noid needed. When a solenoid is energized, the sole-
noid valve shifts, and a fluid passage is opened or
closed (vented or applied), depending on its default
operating state. The result is an apply or release of a
frictional element. The 2/4 and UD solenoids are normally applied,
which by design allow fluid to pass through in their
relaxed or ªoffº state. This allows transaxle limp-in
(P,R,N,2) in the event of an electrical failure. The continuity of the solenoids and circuits are
periodically tested. Each solenoid is turned on or off
depending on its current state. An inductive spike
Fig. 274 Knee Bolster
1 - KNEE BOLSTER
Fig. 275 Instrument Panel Lower Silencer
1 - INSTRUMENT PANEL LOWER SILENCER
Fig. 276 Solenoid/Pressure Switch Assembly
1 - SOLENOID AND PRESSURE SWITCH ASSEMBLY
RS 40TE AUTOMATIC TRANSAXLE21s - 137
SHIFT INTERLOCK SOLENOID (Continued)
(9)Fill the transmission with the recommended fluid.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 41TE/FLUID - STANDARD PROCEDURE)
TRANSMISSION CONTROL RELAY
DESCRIPTION
The transmission control relay (Fig. 302) is located
in the Intelligent Power Module (IPM), which is
located on the left side of the engine compartment
between the battery and left fender.
OPERATION
The Transmission Control Relay is supplied fused
B+ voltage, energized by the PCM, and is used to
supply power to the solenoid pack when the trans-
mission is in normal operating mode. When the relay
is ªoffº, no power is supplied to the solenoid pack and
the transmission is in ªlimp-inº mode. After a control-
ler reset (ignition key turned to the ªrunº position or
after cranking engine), the PCM energizes the relay.
Prior to this, the PCM verifies that the contacts are
open by checking for no voltage at the switched bat-
tery terminals. After this is verified, the voltage at
the solenoid pack pressure switches is checked. After
the relay is energized, the PCM monitors the termi-
nals to verify that the voltage is greater than 3 volts.
TRANSMISSION RANGE SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) is mounted
to the top of the valve body inside the transaxle and can only be serviced by removing the valve body. The
electrical connector extends through the transaxle
case (Fig. 303).
The Transmission Range Sensor (TRS) has four
switch contacts that monitor shift lever position and
send the information to the PCM/TCM.
Fig. 301 Checking Torque Converter Seating
1 - SCALE
2 - STRAIGHTEDGE
Fig. 302 Transmission Control Relay Location
1 - TRANSMISSION CONTROL RELAY
2 - LEFT FENDER
3 - INTELLIGENT POWER MODULE (IPM)
4 - BATTERY
Fig. 303 Transmission Range Sensor (TRS) Location
1 - TRANSMISSION RANGE SENSOR
21s - 150 40TE AUTOMATIC TRANSAXLERS
TORQUE CONVERTER (Continued)
REAR CONTROL PANEL
The rear A/C-heater control centrally mounted in
the headliner allows intermediate seat passengers to
adjust rear air distribution, temperature and blower
motor speed when the center knob on the front A/C-
heater control is set to the Rear position. The rear
A/C-heater control contains:
²a rotary adjustment knob for temperature.
²a rotary adjustment for fan speed control.
DESCRIPTION - AUTOMATIC THREE ZONE
The automatic temperature control (ATC), three
zone, front and rear heating and air conditioning sys-
tem allows both the driver and front occupants and
the rear intermediate occupants to select individual
comfort temperatures.
NOTE: Individual comfort temperatures are the per-
ceived temperature level at the individual seating
areas, NOT the actual passenger compartment air
temperature.
The ATC system includes a particulate air filter.
The filter element is the same size as the air condi-
tioning evaporator to ensure ample capacity. A door
at the base of the HVAC housing below the glove box
provides easy access to the filter element.
The ATC computer utilizes integrated circuitry and
information carried on the programmable communi-
cations interface (PCI) data bus network to monitor
many sensors and switch inputs throughout the vehi-
cle. In response to those inputs, the internal circuitry
and programming of the ATC computer allow it to
control electronic functions and features of the ATC
system. The inputs to the ATC computer are:
²Vehicle Speed/Engine RPM± The ATC com-
puter monitors engine rpm, vehicle speed and mani-
fold absolute pressure information from the
powertrain control module (PCM).
²Coolant Temperature± ATC computer moni-
tors coolant temperature received from the PCM and
converts it to degrees Fahrenheit.
²Ambient Temperature± ATC computer moni-
tors ambient temperature from the compass mini trip
computer (CMTC) and converts it to degrees Fahren-
heit.
²Engine Miscellaneous Sensor Status±ATC
computer monitors A/C disable information from the
PCM.
²Refrigerant Pressure± ATC computer moni-
tors barometric pressure, intake air temperature,
high side pressure and methanol content as broad-
cast by the PCM.
²Door Ajar Status± The ATC computer moni-
tors driver front door, passenger front door, left rear
door, right rear door and liftgate ajar information, asidentified by the body control module (BCM), to
determine if all in-car temperatures should be main-
tained.
²Dimming± The ATC computer monitors dim-
ming status from the BCM to determine the required
level of brightness and will dim accordingly.
²Vehicle Odometer± The ATC computer moni-
tors the vehicle odometer information from the BCM
to prevent flashing the vacuum-flourescent (VF) dig-
ital display icons if the manual motor calibration or
manual cool down tests have failed. Flashing of the
display icons will cease when the vehicle odometer is
greater than 3 miles.
²English/Metric± The ATC computer monitors
the English/Metric information broadcast by the
CMTC. The set temp displays for both the front and
rear control heads will be set accordingly.
²Vehicle Identification Number± The ATC
computer monitors the last eight characters of the
VIN broadcast by the PCM and compares it to the
information stored in EEPROM. If it is different, the
new number will be stored over the old one and a
motor calibration shall be initiated.
²A/C System Information± The ATC computer
will send a message for evaporator temperature too
low, fan blower relay status, evaporator sensor fail-
ure, rear window defogger relay and A/C select.
FRONT CONTROL PANEL
The front A/C-heater control and integral computer
is mounted in the instrument panel and contains:
²a power button which allows the system to be
completely turned off. The display is blank when the
system is off.
²a rocker switch that selects a cool-down rate.
LO-AUTO or HI-AUTO are displayed when the sys-
tem is in automatic operation.
²three rocker switches that select comfort temper-
atures from 15É to 30É C (59É to 85É F), which are
shown in the VF digital display. If the set temp is 15É
C (59É F) and the down button is pressed, the set
temp value will become 13É C (55É F) but the display
will show LO. If the set temp is 29É C (85É F) and the
up button is pressed, the set temp value will become
32É C (90É F) but the display will show HIGH. Tem-
peratures can be displayed in either metric or Fahr-
enheit, which is controlled from the overhead console.
²an air conditioning button that allows the com-
pressor to be turned off. A Snowflake symbol is illu-
minated when air conditioning is on, whether under
manual or automatic control.
²an air recirculation button. A Recirculation sym-
bol appears in the display when the button is
pressed, or when the system exceeds 80 percent cir-
culated air under automatic control due to high air
conditioning demand.
RSHEATING & AIR CONDITIONING24-3
HEATING & AIR CONDITIONING (Continued)
A/C PERFORMANCE TEMPERATURE AND PRESSURE
Ambient Temperature21É C
(70É F)27É C
(80É F)32É C
(90É F)38É C
(100É F)43É C
(110É F)
Left Center Panel
Outlet Discharge Air
Temperature1to8ÉC
(34 to 46É F)3to9ÉC
(37 to 49É F)4 to 10ÉC
(39 to 50É F)6to11ÉC
(43 to 52É F)7 to 18É C
(45 to 65É F)
Discharge Pressure
(High Side Service
Port)1034 to 1724
kPa
(150 to 250 psi)1517 to 2275
kPa
(220 to 330
psi)1999 to 2620
kPa
(290 to 380 psi)2068 to 2965
kPa
(300 to 430 psi)2275 to 3421
kPa
(330 to 450
psi)
Suction Pressure
(Low Side Service
Port)103 to 207 kPa
(15 to 30 psi)117to221
kPa
(17 to 32 psi)138 to 241 kPa
(20 to 35 psi)172 to 269 kPa
(25 to 39 psi)207 to 345
kPa
(30 to 50 psi)
(8) If the air outlet temperature fails to meet the
specifications in the A/C Performance Temperature
and Pressure chart, or if the compressor dischargepressure is high, refer to the Pressure Diagnosis
Chart.
PRESSURE DIAGNOSIS
Condition Possible Causes Correction
Rapid A/C compressor clutch
cycling (ten or more cycles
per minute).1. Low refrigerant system
charge.1. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
Equal pressures, but the
compressor clutch does not
engage.1. No refrigerant in the
refrigerant system.1. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
2. Faulty fuse. 2. Check the fuses in the Integrated Power
Module. Repair the shorted circuit or component
and replace the fuses, if required. Refer to Group
8.
3. Faulty A/C compressor
clutch coil.3. See A/C Compressor Clutch Coil in this group.
Test the compressor clutch coil and replace, if
required.
4. Faulty A/C compressor
clutch relay.4. See A/C Compressor Clutch Relay in this
group. Test the compressor clutch relay and relay
circuits. Repair the circuits or replace the relay, if
required.
5. Improperly installed or
faulty evaporator temperature
sensor.5. See Evaporator Temperature Sensor in this
group. Test the sensor and replace, if required.
6. Faulty A/C pressure
transducer.6. See A/C Pressure Transducer in this group.
Test the sensor and replace, if required.
7. Faulty Powertrain Control
Module (PCM).7. Refer to the proper Diagnostic Procedures
manual for testing of the PCM. Test the PCM and
replace, if required.
24 - 8 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)
MECHANICAL PROBLEMS
Possible causes of insufficient heat due to mechan-
ical problems are as follows:
²Obstructed cowl air intake.
²Obstructed heater system outlets.
²Blend door not functioning properly.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
A/C-heater control panel, the following could require
service:
²Blend door binding.²Faulty blend door actuator.
²Faulty A/C-heater control.
²Faulty related wiring harness or connectors.
²Improper engine coolant temperature.
SPECIFICATIONS
A/C SYSTEM
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood Specifica-
tion Label.
SYSTEM SPECIFICATIONS
Item Description Notes
A/C Compressor Denso - 10S20 (2.5L/3.3L/3.8L engines)
Denso - 10S17 (2.4L engine)ND-8 PAG Oil
Freeze±up Control Evaporator temperature sensor Expansion valve mounted (ATC),
HVAC housing mounted (MTC)-
input to A/C-heater control
module
Low PSI Control A/C pressure transducer Liquid line mounted - input to
Powertrain Control Module (PCM)
- PCM opens compressor clutch
relay above 200 kPa (29 psi)
High PSI Control A/C pressure transducer Liquid line mounted - input to
PCM - PCM opens compressor
clutch relay below 3100 kPa (450
psi)
High Pressure relief valve Compressor mounted - opens
above 3445-4135 kPa (500-600
psi), closes below 2756 kPa (400
psi)
Compressor Clutch Coil Draw 2.2 amps @ 12V 0.5V @ 21É C (70É F)
Compressor Clutch Air Gap 0.35 - 0.60 mm (0.014 - 0.025 in.)
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A/C Compressor Shaft
Bolt17.5 ± 155
A/C Compressor Mounting
Bolts (2.4L/2.5L)28 21 ±
A/C Compressor Mounting
Bolts (3.3L/3.8L)54 40 ±
A/C Compressor Mounting
Bracket Bolts (2.4L)54 40 ±
A/C Condenser Mounting
Bracket Screws5±45
RSHEATING & AIR CONDITIONING24-11
HEATING & AIR CONDITIONING (Continued)
CONTROLS - FRONT
TABLE OF CONTENTS
page page
A/C COMPRESSOR CLUTCH/COIL
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING - A/C
COMPRESSOR CLUTCH COIL...........15
REMOVAL.............................16
INSPECTION..........................17
INSTALLATION.........................17
A/C COMPRESSOR CLUTCH RELAY
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................20
INSTALLATION.........................20
A/C HEATER CONTROL
DESCRIPTION.........................20
STANDARD PROCEDURE - A/C-HEATER
CONTROL CALIBRATION...............20
REMOVAL.............................21
INSTALLATION.........................21
A/C PRESSURE TRANSDUCER
DESCRIPTION.........................21
OPERATION...........................21
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER.......................22
REMOVAL.............................22
INSTALLATION.........................22
BLEND DOOR ACTUATOR
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................23
INSTALLATION.........................23
BLOWER MOTOR RELAY
DESCRIPTION.........................24
OPERATION...........................24
REMOVAL.............................25
INSTALLATION.........................25
BLOWER MOTOR RESISTOR BLOCK
DESCRIPTION.........................26OPERATION...........................26
DIAGNOSIS AND TESTING - BLOWER
MOTOR RESISTOR BLOCK..............26
REMOVAL.............................26
INSTALLATION.........................27
EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................27
OPERATION...........................28
REMOVAL
REMOVAL - AUTOMATIC TEMPERATURE
CONTROL (ATC)......................28
REMOVAL - MANUAL TEMPERATURE
CONTROL (MTC)......................29
INSTALLATION
INSTALLATION - AUTOMATIC
TEMPERATURE CONTROL (ATC).........29
INSTALLATION - MANUAL TEMPERATURE
CONTROL (MTC)......................29
INFRARED TEMPERATURE SENSOR
DESCRIPTION.........................29
OPERATION...........................29
MODE DOOR ACTUATOR
DESCRIPTION.........................30
OPERATION...........................30
REMOVAL.............................30
INSTALLATION.........................31
POWER MODULE - BLOWER MOTOR
DESCRIPTION.........................31
OPERATION...........................31
REMOVAL.............................31
INSTALLATION.........................32
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................32
OPERATION...........................32
REMOVAL.............................33
INSTALLATION.........................33
24 - 14 CONTROLS - FRONTRS
A/C COMPRESSOR CLUTCH/
COIL
DESCRIPTION
The A/C compressor clutch assembly consists of a
stationary electromagnetic A/C clutch field coil with a
zener diode, a pulley bearing and pulley assembly,
and a clutch plate (Fig. 1). A/C clutch field coil and
the pulley bearing and pulley assembly are each
retained on the nose of the compressor front housing
with snap rings. The clutch plate is keyed or splined
to the compressor shaft, and secured with a nut or
bolt (depending on application). These components
provide the means to engage and disengage the com-
pressor from the engine serpentine accessory drive
belt.
The A/C compressor clutch and coil are available
for separate service replacement. The clutch coil
zener diode is integral to the clutch coil pigtail wire
and connector and, if faulty or damaged, the clutch
electromagnetic coil must be replaced.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch plate into contact with the clutch pulley and
drives the compressor shaft. When the coil is not
energized, the pulley freewheels on the clutch hub
bearing, which is part of the pulley.
A zener diode is connected in parallel with the
clutch electromagnetic coil. This diode controls the
dissipation of voltage induced into the coil windingsby the collapsing of the electromagnetic fields that
occurs when the compressor clutch is disengaged.
The zener diode dissipates this induced voltage by
regulating a current path to ground. This arrange-
ment serves to protect other circuits and components
from potentially damaging voltage spikes in the vehi-
cle electrical system that might occur if the voltage
induced in the clutch coil windings could not be dis-
sipated.
The compressor clutch engagement is controlled by
several components: the heater-A/C controls in the
passenger compartment, the A/C pressure transducer
on the liquid line, the evaporator temperature sensor
on the expansion valve for automatic temperature
control (ATC) system or on the HVAC housing for
manual temperature control (MTC) system, the Pow-
ertrain Control Module (PCM) in the engine compart-
ment, and the compressor clutch relay in the
Integrated Power Module (IPM). The PCM may delay
compressor clutch engagement for up to thirty sec-
onds (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL
MODULE - DESCRIPTION - PCM OPERATION).
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the powertrain control
module (PCM) through the A/C compressor clutch
relay, which is located in the integrated power mod-
ule (IPM) in the engine compartment. Begin testing
of a suspected compressor clutch coil problem by per-
forming the preliminary checks.
PRELIMINARY CHECKS
(1) If the compressor clutch will not engage, verify
the refrigerant charge level (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - FRONT/RE-
FRIGERANT - DIAGNOSIS AND TESTING -
REFRIGERANT CHARGE LEVEL). If the refriger-
ant charge level is OK, go to Step 2. If the refriger-
ant charge level is not OK, adjust the refrigerant
charge as required.
(2) If the A/C compressor clutch still will not
engage, disconnect the wire harness connector for the
A/C pressure transducer and check for battery cur-
rent at the connector with the engine running and
the A/C-heater control set to the A/C mode. If OK, go
to TESTS. If not OK, refer to Body Diagnostic Proce-
dures to perform further diagnosis.
TESTS
(1) Verify the battery state of charge (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY -
DIAGNOSIS AND TESTING).
Fig. 1 Compressor Clutch - Typical
1 - CLUTCH PLATE
2 - SHAFT KEY (SOME MODELS)
3 - PULLEY AND BEARING
4 - CLUTCH COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
RSCONTROLS - FRONT24-15
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
3.3L/3.8L - INSTALLATION).
(15) Lower the vehicle.
(16) Reconnect the battery negative cable.
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the A/C-heater control to the A/C
Recirculation Mode, the blower motor switch in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces and provide a higher
compressor clutch torque capability.
A/C COMPRESSOR CLUTCH
RELAY
DESCRIPTION
The compressor clutch relay (Fig. 7) is a Interna-
tional Standards Organization (ISO) micro-relay.
Relays conforming to the ISO specifications have
common physical dimensions, current capacities, ter-
minal patterns, and terminal functions. The ISO
micro-relay terminal functions are the same as a con-
ventional ISO relay. However, the ISO micro-relay
terminal pattern (or footprint) is different, the cur-
rent capacity is lower, and the physical dimensions
are smaller than those of the conventional ISO relay.
The A/C compressor clutch relay is located in the
Integrated Power Module (IPM) in the engine com-
partment. See the fuse and relay layout map molded
into the inner surface of the IPM cover for A/C com-
pressor clutch relay identification and location.The black, molded plastic case is the most visible
component of the A/C compressor clutch relay. Five
male spade-type terminals extend from the bottom of
the base to connect the relay to the vehicle electrical
system, and the ISO designation for each terminal is
molded into the base adjacent to each terminal. The
ISO terminal designations are as follows:
²30 (Common Feed)- This terminal is con-
nected to the movable contact point of the relay.
²85 (Coil Ground)- This terminal is connected
to the ground feed side of the relay control coil.
²86 (Coil Battery)- This terminal is connected
to the battery feed side of the relay control coil.
²87 (Normally Open)- This terminal is con-
nected to the normally open fixed contact point of the
relay.
²87A (Normally Closed)- This terminal is con-
nected to the normally closed fixed contact point of
the relay.
OPERATION
The A/C compressor clutch relay is an electrome-
chanical switch that uses a low current input from
the powertrain control module (PCM) to control the
high current output to the compressor clutch electro-
magnetic coil. The movable common feed contact
point is held against the fixed normally closed con-
tact point by spring pressure. When the relay coil is
energized, an electromagnetic field is produced by the
coil windings. This electromagnetic field draws the
movable relay contact point away from the fixed nor-
mally closed contact point, and holds it against the
fixed normally open contact point. When the relay
coil is de-energized, spring pressure returns the mov-
able contact point back against the fixed normally
closed contact point. The resistor or diode is con-
nected in parallel with the relay coil in the relay, and
helps to dissipate voltage spikes and electromagnetic
interference that can be generated as the electromag-
netic field of the relay coil collapses.
The compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the integrated power module (IPM). The
inputs and outputs of the A/C compressor clutch
relay include:
²The common feed terminal (30) receives a bat-
tery current input from a fuse in the IPM through a
fused B(+) circuit at all times.
²The coil ground terminal (85) receives a ground
input from the PCM through the compressor clutch
relay control circuit only when the PCM electroni-
cally pulls the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the PCM through a fused ignition
switch output (run-start) circuit only when the igni-
tion switch is in the On or Start positions.
Fig. 7 A/C Compressor Clutch Relay
RSCONTROLS - FRONT24-19
A/C COMPRESSOR CLUTCH/COIL (Continued)