Content .. 81 82 83 84 ..

Chrysler Town, Dodge Caravan. Manual - part 83

SHIFT SCHEDULES

As mentioned earlier, the PCM has programming

that allows it to select a variety of shift schedules.
Shift schedule selection is dependent on the follow-
ing:

• Shift lever position

• Throttle position

• Engine load

• Fluid temperature

• Software level
As driving conditions change, the PCM appropri-

ately adjusts the shift schedule. Refer to the follow-
ing chart to determine the appropriate operation
expected, depending on driving conditions.

Schedule

Condition

Expected Operation

Extreme Cold

Oil temperature at start-up below
-16° F

Park, Reverse, Neutral and 2nd
gear only (prevents shifting which
may fail a clutch with frequent
shifts)

Cold

Oil temperature at start-up above
-12° F and below 36° F

– Delayed 2-3 upshift
(approximately 22-31 mph)

– Delayed 3-4 upshift (45-53 mph)

– Early 4-3 costdown shift
(approximately 30 mph)

– Early 3-2 coastdown shift
(approximately 17 mph)

– High speed 4-2, 3-2, 2-1 kickdown
shifts are prevented

– No EMCC

Warm

Oil temperature at start-up above
36° F and below 80 degree F

– Normal operation (upshift,
kickdowns, and coastdowns)

– No EMCC

Hot

Oil temperature at start-up above
80° F

– Normal operation (upshift,
kickdowns, and coastdowns)

– Full EMCC, no PEMCC except to
engage FEMCC (except at closed
throttle at speeds above 70-83 mph)

Overheat

Oil temperature above 240° F or
engine coolant temperature above
244° F

– Delayed 2-3 upshift (25-32 mph)

– Delayed 3-4 upshift (41-48 mph)

– 3rd gear FEMCC from 30-48 mph

– 3rd gear PEMCC from 27-31 mph

Super Overheat

Oil temperature above 260° F

– All

Overheat

shift schedule

features apply

– 2nd gear PEMCC above 22 mph

– Above 22 mph the torque
converter will not unlock unless the
throttle is closed or if a wide open
throttle 2nd PEMCC to 1 kickdown
is made

8E - 14

ELECTRONIC CONTROL MODULES

POWERTRAIN CONTROL MODULE (Continued)

OPERATION - SENSOR RETURN - PCM INPUT

The sensor return circuit provides a low electrical

noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits

within

the

Powertrain

Control

Module

(PCM).

OPERATION - DATA BUS COMMUNICATION
RECEIVE - PCM INPUT

The PCM uses the SCI communication bus to pre-

form engine diagnostics and flash operations. The
transmission side of the PCM uses the SCI commu-
nication bus to flash new software. However, diagnos-
tics is performed via the vehicles J1850 bus for the
transmission side of the PCM.

OPERATION - IGNITION SENSE - PCM INPUT

The ignition sense input informs the Powertrain

Control Module (PCM) that the ignition switch is in
the crank or run position.

OPERATION - PCM GROUND

Ground is provided through multiple pins of the

PCM connector. Depending on the vehicle there may
be as many as two different ground pins. There are
power grounds and sensor grounds.

The power grounds are used to control the ground

side relays, solenoids, ignition coil or injectors. The
signal ground is used for any input that uses sensor
return for ground, and the ground side of any inter-
nal processing component.

The PCM case is shielded to prevent RFI and EMI.

The PCM case is grounded and must be firmly
attached to a good, clean body ground.

Internally all grounds are connected together, how-

ever there is noise suppression on the sensor ground.
For EMI and RFI protection the housing and cover
are also grounded separately from the ground pins.

OPERATION

OPERATION - 8-VOLT SUPPLY - PCM OUTPUT
- SBEC CONTROLLER

The PCM supplies 8 volts to the crankshaft posi-

tion sensor, camshaft position sensor.

OPERATION - 5 VOLT SUPPLY - PCM OUTPUT

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

• Ambient Temperature sensor

• Battery temperature

• Camshaft Position Sensor (NGC)

• Crankshaft Position Sensor (NGC)

• Electronic Throttle Control (1.6L)

• Engine coolant temperature sensor

• Inlet Air Temperature Sensor

• Knock sensor

• Linear EGR solenoid (if equipped)

• Manifold absolute pressure sensor

• Oil Pressure Switch

• Pedal Position Sensor (1.6L)

• Throttle position sensor

• Vehicle Speed Sensor

STANDARD PROCEDURE

STANDARD PROCEDURE - OBTAINING
DIAGNOSTIC TROUBLE CODES

BULB CHECK

Key on: Bulb illuminated until vehicle starts, as

long as all once per trip (readiness) monitors com-
pleted. If monitors have not been completed, then:
Key on: bulb check for about 5 to 8 seconds, lamp
then flashes if once per trip (readiness) monitors
have not been completed until vehicle is started,
then MIL is extinguished.

OBTAINING DTC’S USING DRB SCAN TOOL

(1) Connect the DRB scan tool to the data link

(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.

(2) Turn the ignition switch on and access the

“Read Fault” screen.

(3) Record all the DTC’s and “freeze frame” infor-

mation shown on the DRB scan tool.

(4) To erase DTC’s, use the “Erase Trouble Code”

data screen on the DRB scan tool. Do not erase any
DTC’s until problems have been investigated
and repairs have been performed.

STANDARD PROCEDURE - PINION FACTOR
SETTING

NOTE: This procedure must be performed if the
PCM/TCM

has

been

replaced

with

NEW

replacement unit. Failure to perform this procedure
will result in an inoperative or improperly calibrated
speedometer.

The vehicle speed readings for the speedometer are

taken from the output speed sensor. The PCM/TCM
must be calibrated to the different combinations of
equipment (final drive and tires) available. Pinion
Factor allows the technician to set the Powertrain/
Transmission Control Module initial setting so that
the speedometer readings will be correct. To properly

ELECTRONIC CONTROL MODULES

8E - 15

POWERTRAIN CONTROL MODULE (Continued)

read and/or reset the Pinion Factor, it is necessary to
use a DRBIII

t scan tool.

(1) Plug the DRBIII

t scan tool into the diagnostic

connector located under the instrument panel.

(2) Select the Transmission menu.
(3) Select the Miscellaneous menu.
(4) Select Pinion Factor. Then follow the instruc-

tions on the DRBIII

t scan tool screen.

STANDARD PROCEDURE - QUICK LEARN
PROCEDURE

The quick learn procedure requires the use of the

DRBIII

t scan tool. This program allows the PCM/

TCM to recalibrate itself. This will provide the best
possible transaxle operation.

NOTE: The quick learn procedure should be per-
formed if any of the following procedures are per-
formed:

• Transaxle Assembly Replacement

• Powertrain/Transmission

Control

Module

Replacement

• Solenoid/Pressure Switch Assembly Replacement

• Clutch Plate and/or Seal Replacement

• Valve Body Replacement or Recondition
To perform the Quick Learn Procedure, the follow-

ing conditions must be met:

• The brakes must be applied

• The engine speed must be above 500 rpm

• The throttle angle (TPS) must be less than 3

degrees

• The shift lever position must stay until

prompted to shift to overdrive

• The shift lever position must stay in overdrive

after the Shift to Overdrive prompt until the
DRBIII

t indicates the procedure is complete

• The calculated oil temperature must be above

60° and below 200°

(1) Plug the DRBIII

t scan tool into the diagnostic

connector. The connector is located under the instru-
ment panel.

(2) Go to the Transmission screen.
(3) Go to the Miscellaneous screen.
(4) Select Quick Learn Procedure. Follow the

instructions of the DRBIII

t to perform the Quick

Learn Procedure.

REMOVAL

REMOVAL - SBEC CONTROLLER

(1) Disconnect the negative battery cable.
(2) Remove the battery shield, refer to the Battery

section for more information.

(3) Remove the 2 upper PCM bracket bolts (Fig.

11).

(4) Remove the 2 PCM connectors.
(5) Remove the headlamp, refer to the Lamps sec-

tion for more information.

(6) Remove the lower PCM mounting bolt (Fig. 12).
(7) Remove PCM.

Fig. 11 PCM

1 - Attaching Bolts

Fig. 12 PCM LOWER BOLT

8E - 16

ELECTRONIC CONTROL MODULES

POWERTRAIN CONTROL MODULE (Continued)

REMOVAL - NGC CONTROLLER

The PCM engine control strategy prevents reduced

idle speeds until after the engine operates for 320 km
(200 miles). If the PCM is replaced after 320 km (200
miles) of usage, update the mileage and vehicle iden-
tification number (VIN) in the new PCM. Use the
DRBIII

t scan tool to change the millage and VIN in

the PCM. If this step is not done a Diagnostic Trou-
ble Code (DTC) may be set. Refer to the appropriate
Powertrain Diagnostic Manual and the DRBIII

t scan

tool.

(1) Turn wheels to the left.
(2) Disconnect the negative battery cable.
(3) Raise vehicle and support.
(4) Remove the left front wheel well splash shield

(Fig. 13).

(5) Unlock and disconnect the electrical connectors

(Fig. 14).

(6) Remove 3 screws from PCM to mounting

bracket.

(7) Remove the PCM.

INSTALLATION

INSTALLATION - SBEC CONTROLLER

(1) Install the PCM.
(2) Install the lower PCM mounting bolt. Tighten

bolt.

(3) Install the 2 upper PCM bracket bolts. Tighten

bolt.

(4) Install the headlamp, refer to the Lamps sec-

tion for more information.

(5) Install the 2 PCM connectors.

(6) Install the battery shield, refer to the Battery

section for more information.

(7) Connect the negative battery cable.

INSTALLATION

The PCM engine control strategy prevents reduced

t scan tool to change the millage and VIN in

the PCM. If this step is not done a diagnostic trouble
code (DTC) may be set and SKIM must be done or
car will not start if it is a SKIM equipped car. If a
SKIM car you must do a secret key transfer also.

NGC CONTROLLER LOCATION

Fig. 13 SPLASH SHIELD

Fig. 14 NGC CONTROLLER

ELECTRONIC CONTROL MODULES

8E - 17

POWERTRAIN CONTROL MODULE (Continued)

Content .. 81 82 83 84 ..