Chrysler Stratus Convertible. Manual — part 18

output voltage to the PCM varies from approximately
0.5 volt at minimum throttle opening (idle) to a max-
imum of 3.7 volts at wide open throttle.

Along with inputs from other sensors, the PCM

uses TPS input to determine current engine operat-
ing conditions. The PCM also adjusts fuel injector
pulse width and ignition timing based on these
inputs.

VEHICLE SPEED AND DISTANCE—PCM INPUT

DESCRIPTION

The vehicle speed output sensor is located in the

transmission (Fig. 12).

OPERATION

The transaxle control module (TCM) supplies the

vehicle speed signal to the PCM based on the output
shaft speed. The PCM sends a 5 volt signal to the
TCM. The TCM switches this signal to a ground, and
then opens the circuit at a rate of 8000 pulses per
mile. When the PCM counts 8000 pulses, the PCM
assumes the vehicle has traveled one mile. The out-
put speed sensor is located on the side of the tran-
saxle (Fig. 12).

The speed and distance signals, along with a closed

throttle signal from the TPS, determine if a closed
throttle deceleration or normal idle condition (vehicle
stopped) exists. Under deceleration conditions, the
PCM adjusts the idle air control motor to maintain a
desired MAP value. Under idle conditions, the PCM
adjusts the idle air control motor to maintain a
desired engine speed.

AUTOMATIC SHUTDOWN RELAY—PCM
OUTPUT

DESCRIPTION

The ASD relay and fuel pump relay are located in

the Power Distribution Center (PDC) near the Air
Cleaner (Fig. 13). The inside top of the PDC cover
has a label showing relay and fuse location. They are
ISO relays.

OPERATION

The PCM operates the Automatic Shut Down

(ASD) relay and fuel pump relay through one ground
path. The PCM operates them by switching the
ground path for the relays on and off.

The ASD relay connects battery voltage to the fuel

injectors and ignition coil. The fuel pump relay con-
nects battery voltage to the fuel pump.

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 posi-
tion, the PCM monitors the crankshaft position sen-
sor

and

camshaft

position

sensor

signals

to

determine engine speed. If the PCM does not receive
a crankshaft position sensor signal and camshaft
position sensor signal when the ignition switch is in
the Run position, it de-energizes both relays. When
the relays are de-energized, battery voltage is not
supplied to the fuel injectors, ignition coil and fuel
pump.

Fig. 11 Throttle Position Sensor—2.5L Engine

1 – THROTTLE BODY
2 – THROTTLE POSITION SENSOR

Fig. 12 Output Speed Semsor— Automatic

Transaxle

1 – OUTPUT SPEED SENSOR
2 – PARK/NEUTRAL SWITCH (BLACK)
3 – TRANSMISSION RANGE SWITCH

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DESCRIPTION AND OPERATION (Continued)

PROPORTIONAL PURGE SOLENOID—PCM
OUTPUT

DESCRIPTION

The solenoid attaches to a bracket near the front

engine mount (Fig. 14). To operate correctly, the sole-
noid must be installed with the electrical connector
on top.

OPERATION

The purge solenoid regulates the rate of vapor flow

from the EVAP canister to the throttle body. The
PCM operates the solenoid.

During the cold start warm-up period and the hot

start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged.

The proportional purge solenoid operates at a fre-

quency of 200 hz and is controlled by an engine con-
troller circuit that senses the current being applied
to the proportional purge solenoid and then adjusts
that current to achieve the desired purge flow. The
proportional purge solenoid controls the purge rate of
fuel vapors from the vapor canister and fuel tank to
the engine intake manifold.

IDLE AIR CONTROL MOTOR—PCM OUTPUT

DESCRIPTION

The Idle Air Control (IAC) motor is mounted on the

throttle body. The PCM operates the idle air control
motor (Fig. 15) or (Fig. 16).

Fig. 13 Power Distribution Center (PDC)

1 – BATTERY POSITIVE
2 – BATTERY GROUND
3 – AIR CLEANER
4 – PCM
5 – PDC
6 – TCM

Fig. 14 Proportional Purge Solenoid

1 – TEST PORT
2 – PROPORTIONAL PURGE SOLENOID

Fig. 15 Idle Air Control Motor Air Bypass Passage—

2.4L

1 – IDLE AIR CONTROL MOTOR
2 – TPS

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DESCRIPTION AND OPERATION (Continued)

OPERATION

The PCM adjusts engine idle speed through the

idle air control motor to compensate for engine load,
coolant temperature or barometric pressure changes.

The throttle body has an air bypass passage that

provides air for the engine during closed throttle idle.
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

IAC motor pintle in and out of the bypass passage.
The adjustments are based on inputs the PCM
receives. The inputs are from the throttle position
sensor, crankshaft position sensor, coolant tempera-
ture sensor, MAP sensor, vehicle speed sensor and
various switch operations (brake, park/neutral, air
conditioning).

DATA LINK CONNECTOR

DESCRIPTION

The data link connector is located inside the vehi-

cle, under the instrument panel, at the driver’s kick
panel (Fig. 17).

OPERATION

The data link connector (diagnostic connector)

links the DRB scan tool with the Powertrain Control
Module (PCM). Refer to On-Board Diagnostics in the
Emission Control section.

MALFUNCTION INDICATOR (CHECK ENGINE)
LAMP—PCM OUTPUT

DESCRIPTION

Refer to the Instrument Panel Systems for more

information.

OPERATION

The PCM supplies the malfunction indicator (check

engine) lamp on/off signal to the instrument panel
through the CCD Bus. The CCD Bus is a communi-
cations port. Various modules use the CCD Bus to
exchange information.

The 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 (MIL) stays on

continuously, when the PCM has entered a Limp-In
mode or identified a failed emission component. Dur-
ing Limp-in Mode, the PCM attempts to keep the
system operational. The MIL signals the need for
immediate service. In limp-in mode, the PCM com-
pensates for the failure of certain components that
send incorrect signals. The PCM substitutes for the
incorrect signals with inputs from other sensors.

If the PCM detects active engine misfire severe

enough to cause catalyst damage, it flashes the MIL.
At the same time the PCM also sets a Diagnostic
Trouble Code (DTC).

For signals that can trigger the MIL (Check

Engine Lamp) refer to the On-Board Diagnos-
tics Chart.

Fig. 16 Idle Air Control Motor Air Bypass Passage—

2.5L

1 – THROTTLE BODY
2 – IDLE AIR CONTROL MOTOR
3 – THROTTLE POSITION SENSOR

Fig. 17 Data Link (Diagnostic) Connector

1 – HOOD RELEASE
2 – DIAGNOSTIC CONNECTOR
3 – DRIVER’S SIDE KICK PANEL

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DESCRIPTION AND OPERATION (Continued)

RADIATOR FAN RELAYS—PCM OUTPUT

DESCRIPTION

The radiator fan relays are located in the PDC.

The inside top of the PDC cover has a label showing
relay and fuse location.

OPERATION

The PCM energizes the radiator fans through

either the low or high speed radiator fan relay. The
PCM controls the ground circuit for the coil side of
the relay. Power for both relay coils is supplied
through a 10 amp fuse in the PDC. Power for both
relay contacts is supplied power through a 40 amp
fuse in the PDC. Refer to the Wiring Diagrams for
circuit information.

The PCM monitors the A/C compressor discharge

(high side) pressure through the air conditioning
pressure transducer. Depending on engine coolant
temperature and A/C system high side pressure, both
fans operate at either low or high speed.

TACHOMETER—PCM OUTPUT

DESCRIPTION

Refer to the Instrument panel System for more

information.

OPERATION

The tachometer receives its information across the

CCD Bus from the Body Control Module (BCM).
Information on engine RPM is transmitted from the
Powertrain Control Module (PCM) across the CCD
Bus to the BCM. The BCM calculates the position of
the tachometer pointer based on the input from the
PCM and adjusts the position of the gauge pointer to
the necessary position. This signal is sent over the
CCD Bus to the instrument cluster.

5 VOLT SUPPLY—PCM OUTPUT

OPERATION

The PCM supplies 5 volts to the following sensors:
• A/C pressure transducer

• Engine coolant temperature sensor

• Manifold absolute pressure sensor

• Throttle position sensor

• Linear EGR solenoid

8-VOLT SUPPLY—PCM OUTPUT

OPERATION

The PCM supplies 8 volts to the crankshaft posi-

tion sensor, camshaft position sensor.

THROTTLE BODY

DESCRIPTION

The throttle body mounts to the intake manifold.

The throttle position sensor and idle air control motor
attach to the throttle body (Fig. 18) or (Fig. 19).

Fig. 18 Throttle Body—2.4L Engines

1 – THROTTLE SHIELD
2 – PURGE HOSE
3 – THROTTLE POSITION SENSOR
4 – IDLE AIR CONTROL MOTOR

Fig. 19 Throttle Body—2.5L Engine

1 – PURGE HOSE
2 – EGR TUBE
3 – AIS
4 – TPS

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DESCRIPTION AND OPERATION (Continued)