1993 CHEVROLET PLYMOUTH ACCLAIM reset

The PCM may receive a closed throttle input from
the throttle position sensor (TPS) when it senses an
abrupt decrease in manifold pressure. This indicates
a hard deceleration. The PCM may reduce injector
firing to once per engine revolution. This helps main-
tain better control of the air-fuel mixture. During a deceleration condition, the PCM grounds
the exhaust gas recirculation (EGR) solenoid. When
the PCM grounds the solenoid, preventing EGR.
WIDE OPEN THROTTLE MODE This is an OPEN LOOP mode. During wide-open-
throttle operation, the following inputs are received
by the PCM:
² engine coolant temperature
² crankshaft position (distributor pick-up)
² manifold absolute pressure
² engine speed (distributor pick-up)
² throttle position
When the PCM senses wide open throttle condition
through the throttle position sensor (TPS) it will:
² Provide a ground for the electrical EGR transducer
(EET) solenoid. When the PCM grounds the solenoid,
the EGR system stops operating.
² De-energize the air conditioning relay. This dis-
ables the air conditioning system. 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 (Fig. 19) is located at
the left end of the air intake plenum. The throttle
body houses the throttle position sensor and the idle
air control motor. Air flow through the throttle body
is controlled by a cable operated throttle blade lo-
cated in the base of the throttle body.
FUEL SUPPLY CIRCUIT
Fuel is supplied to the fuel rail by an electric pump
mounted in the fuel tank. The pump inlet is fitted
with a strainer to prevent water and other contami-
nants from entering the fuel supply circuit. Fuel pressure is controlled to a preset level above
intake manifold pressure by a pressure regulator.
The pressure regulator is mounted on the fuel rail.
The regulator uses intake manifold pressure as a ref-
erence.
Fig. 19 Throttle Body
Ä FUEL SYSTEMS 14 - 123

the PCM determines crankshaft position, it begins
energizing the injectors in sequence.The auto shutdown (ASD) relay supplies battery
voltage to the injectors. The PCM provides the
ground path for the injectors. By switching the
ground path on and off, the PCM adjusts injector
pulse width. Pulse width is the amount of time the
injector is energized. The PCM adjusts injector pulse
width based on inputs it receives.
IGNITION COILÐPCM OUTPUT
The coil assembly consists of 3 molded coils to-
gether (Fig. 18). The coil assembly is mounted on the
intake manifold. High tension leads route to each
cylinder from the coil. The coil fires two spark plugs
every power stroke. One plug is the cylinder under
compression, the other cylinder fires on the exhaust
stroke. The PCM determines which of the coils to
charge and fire at the correct time.
The auto shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary, causing the
spark. The PCM will de-energize the ASD relay if it
does not receive the crankshaft position sensor and
camshaft position sensor inputs. Refer to Auto Shut-
down (ASD) Relay/Fuel Pump RelayÐPCM Output
in this section for relay operation.
RADIATOR FAN RELAYÐPCM OUTPUT
The radiator fan is energized by the PCM through
the radiator fan relay. The radiator fan relay is lo-
cated on the drivers side fender well near the PCM
(Fig. 14). The PCM grounds the radiator fan relay
when engine coolant reaches a predetermined tem-
perature or the A/C system head pressure is high.
SPEED CONTROL SOLENOIDSÐPCM OUTPUT
The speed control vacuum and vent solenoids are
operated by the PCM. When the PCM supplies a ground to the vacuum and vent solenoids, the speed
control system opens the throttle blade. When the PCM
supplies a ground only to the vent solenoid, the throttle
blade holds position. When the PCM removes the
ground from both the vacuum and vent solenoids, the
throttle blade closes. The PCM balances the two sole-
noids to maintain the set speed. Refer to Group 8H for
speed control information.
TACHOMETERÐPCM OUTPUT
The PCM supplies engine RPM to the instrument
panel tachometer through the CCD Bus. The CCD Bus
is a communications port. Various modules use the
CCD Bus to exchange information. Refer to Group 8E
for more information.
MODES OF OPERATION
As input signals to the PCM change, the PCM
adjusts its response to output devices. For example, the
PCM must calculate a different injector pulse width
and ignition timing for idle than it does for wide open
throttle (WOT). There are several different modes of
operation that determine how the PCM responds to the
various input signals. There are two different areas of operation, Open
Loop and Closed Loop. During Open Loop modes the PCM receives input
signals and responds according to preset PCM pro-
gramming. Input from the oxygen (O
2) sensor is not
monitored during Open Loop modes. During Closed Loop modes the PCM does monitor
the oxygen (O
2) sensor input. This input indicates to
the PCM whether or not the calculated injector pulse
width results in the ideal air-fuel ratio of 14.7 parts air
to 1 part fuel. By monitoring the exhaust oxygen
content through the O
2sensor, the PCM can fine tune
the injector pulse width. Fine tuning injector pulse
width allows the PCM to achieve optimum fuel
economy combined with low emissions. The 3.3L multi-port fuel injection system has the
following modes of operation:
² Ignition switch ON (Zero RPM)
² Engine start-up
² Engine warm-up
² Cruise (Idle)
² Acceleration
² Deceleration
² Wide Open Throttle
² Ignition switch OFF
The engine start-up (crank), engine warm-up, and
wide open throttle modes are OPEN LOOP modes.
Under most operating conditions, the acceleration,
deceleration, and cruise modes, with the engine at
operating temperature are CLOSED LOOP modes.
Fig. 18 Coil PackÐ3.3L Engine
Ä FUEL SYSTEMS 14 - 153

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

(16) Connect the battery ground (negative) cable.
Test the operation of the lights and horns. If applica-
ble, reset the clock and radio.
STEERING COLUMN COMPONENT SERVICE
The Acustar tilt and standard steering columns
(Fig.1) have been designed to be serviced as an as-
sembly; less wiring, switches, shrouds, steering
wheel, etc. Also most steering column components
can be serviced without removing the steering col-
umn from the vehicle. For additional information on
electrical components refer to Group 8H Electrical.
GEAR SHIFT LEVER
The gear shift lever (if equipped) is a serviceable
component of the Acustar steering column assembly.
REMOVE (1) Support the steering column assembly as
shown in (Fig. 1) using a suitable size socket. (2) Using a drift of the appropriate size drive the
roll pin out of the steering column and gear shift le-
ver (Fig. 1). Remove the gear shift lever from the
steering column assembly.
INSTALL (1) Support the steering column assembly as
shown in (Fig. 1) using a suitable size socket. (2) Install the gear shift lever into the steering col-
umn assembly. Align the roll pin holes in the gear
shift lever and the steering column assembly. (3) Carefully Install the roll pin into the steering
column assembly and through the shift lever. If the
roll pin binds check the alignment on the holes. Be
sure roll pin is fully installed into the steering col-
umn assembly.
IGNITION SWITCH SERVICE
TEST AND REPAIR
If the ignition switch effort seems to be excessive
due to binding. Follow the procedure outlined below
to determine the cause.
When service procedures are performed on the
Acustar steering column there are certain areas of the
column that can not be tampered with. If a problem re-
lated to these areas of the steering column are detected.
The entire steering column (less the removable compo-
nents) should be replaced see (Fig. 2 and 3).
(1) Remove ignition switch from steering column.
Refer to Group 8H Electrical.
(2) Using a key cylinder, check the turning effort
of the switch.
² If the ignition switch binds look for the following
conditions.
Fig. 1 Gear Shift Lever Removal
Fig. 2 Steering Column Non-Serviceable Components
19 - 34 STEERING Ä

CAUTION: Be sure crossover bellcrank does NOT
move when tightening adjusting screw (Fig. 10).
CAUTION: Proper torque to the crossover cable ad-
justing screw is very important (Fig. 10).
(6) Remove lock pin from gearshift housing and re-
install lock pin (so long end is up) in gear shift hous-
ing. Tighten lock pin to 8 N Im (70 in. lbs.).
(7) Check for shift into first and reverse.
(8) Gearshift mechanism and cables are now func-
tioning properly.
IN-CAR TRANSAXLE DISASSEMBLE/ASSEMBLE
The following items can be serviced without remov-
ing the transaxle from the vehicle:
² Gear shift housing
² Synchronizers
² Intermediate shaft speed gears
² Input shaft
² Reverse idler gear and shaft
² Shift forks and pads
² Shift rails ²
Roller detents
² Speedometer pinion
² All external covers
Observe following procedure:
(1) Disconnect negative cable from battery.
(2) Remove both shift cables from shift cover levers.
(3) Remove left front wheel and tire assembly and
left splash shield. (4) Place drain pan under transaxle and remove
transaxle rear end cover. (5) Push out the fifth fork roll pin and slide the fifth
fork and synchronizer sleeve off the rail/hub. (6) Remove the fifth hub snap ring, hub assembly
and speed gear. (7) Remove fifth gear nut and fifth input gear.
(8) Remove the bearing retainer plate, interlock
plate and shuttles.
CAUTION: Before removing the gearshift housing
assembly, reverse the lock pin (so the long end is
down) and insert lock pin into the same threaded
hole. This procedure will save time when the gear
shift housing assembly is reinstalled. (9) Remove selector shaft housing bolts (note the two
pilot bolts) and remove housing. (10) Remove roller detents and springs, noting that
the rollers align with the shift rails. (11) Push out the 1-2 and 3-4 lug roll pins, remove
the reverse pivot lever and fifth rail C-Clip. If a roll
pin or C-Clip falls, be sure to remove it from the
bottom of the case. (12) Pull out the fifth shift rail and remove the fifth
shift lug and interlock pin. If the pin falls, be sure to
remove it from the bottom of the case. (13) Remove the intermediate shaft ball bearing
snap ring and the bearing support plate. (14) Remove reverse shift rail and lug assembly.
(15) Remove the reverse idler shaft and gear assem-
bly. (16) Rotate the 1-2 shift lug and rail, and 3-4 shift
lug towards the front of the vehicle. (17) Firmly grasp both the input and intermediate
shaft assemblies and pull them out of the transmission
with the 1-2 and 3-4 shift rails, lugs and forks. The differential assembly can only be serviced
by removing the complete transaxle from the
vehicle because bearing preload must be reset. The components listed in the first paragraph can now
be serviced. Refer to the appropriate subassembly
recondition section.
To reassemble the transaxle in the vehicle, reverse
the above procedure using the proper sealants. Fill the
transaxle with SAE 5W-30 engine oil to the bottom of
the fill hole in the end cover.
Fig. 9 Install Cables
Fig. 10 Adjusting Crossover Cable
21 - 4 TRANSAXLE Ä

first separator plate and watch carefully for the pis-
ton to move forward. The piston should return to its
original position after the air pressure is removed.
UNDERDRIVE CLUTCH
Because this clutch piston cannot be seen, its oper-
ation is checked by function. Air pressure is applied
to the low/reverse and the 2/4 clutches. This locks
the output shaft. Use a piece of rubber hose wrapped
around the input shaft and a pair of clamp-on pliers
to turn the input shaft. Next apply air pressure to
the underdrive clutch. The input shaft should not ro-
tate with hand torque. Release the air pressure and
confirm that the input shaft will rotate.
FLUID LEAKAGE-TORQUE CONVERTER HOUSING
AREA
(1) Check for source of leakage.
Since fluid leakage at or around the torque con-
verter area may originate from an engine oil leak,
the area should be examined closely. Factory fill
fluid is dyed red and, therefore, can be distinguished
from engine oil. (2) Prior to removing the transaxle, perform the
following checks: When leakage is determined to originate from the
transaxle, check fluid level prior to removal of the
transaxle and torque converter. High oil level can result in oil leakage out the vent
in the manual shaft. If the fluid level is high, adjust
to proper level. After performing this operation, inspect for leak-
age. If a leak persists, perform the following opera-
tion on the vehicle to determine if it is the torque
converter or transaxle that is leaking.
LEAKAGE TEST PROBE
(1) Remove torque converter housing dust shield.
(2) Clean the inside of torque converter housing
(lower area) as dry as possible. A solvent spray fol-
lowed by compressed air drying is preferable. (3) Fabricate and fasten test probe (Fig. 4) securely
to convenient dust shield bolt hole. Make certain
torque converter is cleared by test probe. Tool must be
clean and dry. (4) Run engine at approximately 2,500 rpm with
transaxle in neutral, for about 2 minutes. Transaxle
must be at operating temperature. (5) Stop engine and carefully remove tool.
(6) If upper surface of test probe is dry, there is no
torque converter leak. A path of fluid across probe
indicates a torque converter leak. Oil leaking under the
probe is coming from the transaxle torque converter
area. (7) Remove transaxle and torque converter assembly
from vehicle for further investigation. The fluid should
be drained from the transaxle. Re install oil pan (with
MOPAR tAdhesive Sealant) at specified torque.
Possible sources of transaxle torque converter area
fluid leakage are: (1) Torque converter hub seal.
² Seal lip cut, check torque converter hub finish.
² Bushing moved and/or worn.
² Oil return hole in pump housing plugged or omitted.
² Seal worn out (high-mileage vehicles).
(2) Fluid leakage at the outside diameter from pump
housing O-ring. (3) Fluid leakage at the front pump to case bolts.
Check condition of washers on bolts and use new bolts,
if necessary. (4) Fluid leakage due to case or front pump housing
porosity.
TORQUE CONVERTER LEAKAGE
Possible sources of torque converter leakage are:
² Torque converter weld leaks at the out side (periph-
eral) weld.
² Torque converter hub weld.
Hub weld is inside and not visible. Do not
attempt to repair. Replace torque converter. If the torque converter must be replaced, refer
to Torque Converter Clutch Break-in Procedure
in this section. This procedure will reset the
transmission control module break-in status.
Failure to perform this procedure may cause
transaxle shutter.
AIR PRESSURE TEST OF TRANSAXLE
Fabricate equipment needed for test as shown in
Figures 5 and 6. The transaxle should be prepared for pressure test as
follows after removal of the torque converter: (1) Plug dipstick tube and plug oil cooler line fitting.
Remove vent from manual shaft and in stall a 1/8 inch
pipe plug.Fig. 4 Leak Locating Test Probe Tool
Ä TRANSAXLE 21 - 97

If the torque converter has been replaced, refer
to Torque Converter Clutch Break-in Procedure
in this section. This procedure will reset the transmission control module break-in status.
Failure to perform this procedure may cause
transaxle shutter. Check and/or adjust gear shift cable.
Refill transaxle with MOPAR tATF PLUS (Auto-
matic Transmission Fluid) Type 7176.
SOLENOID ASSEMBLY-REPLACE
Fig. 9 Lower Transaxle Assembly
Fig. 1 Input Speed Sensor
Fig. 6 Remove Starter Assembly
Fig. 7 Position Transmission Jack
Fig. 8 Remove Left Transmission Mount
Ä TRANSAXLE 21 - 101

SPEED SENSOR-OUTPUT
CAUTION: When disconnecting speed sensor con-
nector, be sure that the weather seal does not fall
off or remain in old sensor. The output speed sensor is located to the left of the
manual shift lever (Fig. 8).
TRANSMISSION CONTROL MODULE
When replacing a transmission control module, do
not interchange transmission control modules with
previous year transmission control modules. If a
same year transmission control module is being used
from a different vehicle, the following procedures
must be performed before operating the transaxle:
² Quick Learn Procedure
² Torque Converter Clutch Break-in Procedure
² Electronic Pinion Procedure
The transmission control module is located on the
passenger side of the engine compartment. It is held
in place by four mounting screws. If the transmission control module has been
replaced, the following procedures must be per-
formed:
² ``Quick Learn Procedure''. This procedure will al-
low the transmission control module to learn the
characteristics of the vehicle.
² ``Electronic Pinion Procedure''. This procedure will
reprogram settings within the transmission control
module to compensate for different tire sizes and fi-
nal drive ratios.
² ``Converter Clutch Break-In Procedure'' This proce-
dure will reset the torque converter clutch status.
REMOVAL AND INSTALLATION
(1) Loosen 60 way retaining screw, located in the
center of the 60 way connector. Then disconnect the
60 way connector on transmission control module. (2) Remove transmission control module mounting
screws and lift module from vehicle. To install, reverse removal procedure.
TRANSAXLE QUICK LEARN PROCEDURE
The quick learn procedure requires the use of the
DRB II scan tool and the 1993 DRB II scan tool car-
tridge. This program allows the electronic transaxle sys-
tem to recelebrate itself to provide the best possible
transaxle operation. The quick learn procedure
should be performed if any of the following proce-
dures are performed:
² Transaxle Assembly Replacement
² Transmission Control Module Replacement
² Solenoid Pack Replacement
² Clutch Plate and/or Seal Replacement
² Valve Body Replacement or Recondition
(1) Plug the DRB II scan tool into the blue CCD
Buss connector. The connector is located under the
instrument panel on the drivers side of the vehicle. (2) Insert the 1993 DRB II scan tool cartridge into
the DRB II scan tool. (3) The red and green lights on the DRB II scan
tool will light up and then begin flashing. Wait until
the lights stop flashing before continuing with this
procedure. (4) Press the number 4 key on the DRB II scan
tool key pad. Item number 4 will not appear on the
DRB II scan tool screen unless you scroll down. It is
not necessary to scroll down to be able to choose item
4. (5) Press the number 2 on the DRB II scan tool
key pad (Transmission). (6) Press the number 1 on the DRB II scan tool
key pad. Wait for the DRB II scan tool to perform the
following three tests before continuing (These tests
are done automatically by the DRB II scan tool).
² Buss Test
² Initialize
² Controller Part Number
Fig. 7 Park/Neutral Position Switch
Fig. 8 Output Speed Sensor
Ä TRANSAXLE 21 - 103