Chrysler Town, Dodge Caravan. Manual — part 991
NOTES
vi
1.0
INTRODUCTION
IMPORTANT
The 2003 RS model year vehicles, will use both
the standard EATX controlled transmission with
3.3/3.8L engines and the new NGC controlled trans-
mission with 2.4L engine.
NGC CONTROLLER
New for 2003 model year, RS vehicles will inte-
grate the Transmission Control Module and Power-
train Control Module into a single control module.
This new module is the Next Generation Controller
for DaimlerChrysler and will be referred to as the
Powertrain Control Module (PCM).
Some of the changes you will see are several new
Diagnostics Trouble Codes and supporting diagnos-
tic procedures which reflect the new combined mod-
ule technology. The PCM will have four color coded
connectors, C1 through C4, (C1-BLK, C2-GRAY,
C3-WHITE, C4-GREEN), each PCM connector will
have 38 pins. Two new tools are used for probing
and repairing the new PCM connectors. Miller tool
#3638, and Miller tool #8815. Miller tool #3638 is
designed to release the pins from the PCM harness
connectors. You must use the Miller tool #3638 to
release the harness connector terminals or harness
connector or terminal damage will occur. Miller tool
#8815 was designed for probing the PCM harness
connectors. You must use Miller tool #8815 for
probing the PCM terminals or damage to the ter-
minal will occur resulting in a poor terminal to pin
connection. There are also new Verification tests
and module replacement procedures for the new
PCM.
The procedures contained in this manual include
all of the specifications, instructions, and graphics
needed to diagnose,
*41TE (EATX) Electronic Automatic Transmission
problems
*41TE (NGC) Electronic Automatic Transmission
problems
The diagnostics in this manual are based on the
failure condition or symptom being present at the
time of diagnosis.
When repairs are required, refer to the appropri-
ate volume of the service manual for the proper
removal and repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added and/or carryover
systems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
TROUBLE CODE. It is recommended that you
review the entire manual to become familiar with
all new and changed diagnostic procedures.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or recommendations, please fill
out the form at the back of the book and mail it back
to us.
1.1
SYSTEM COVERAGE
The diagnostic procedure manual covers all 2003
RS vehicles equipped with a 41TE transaxle.
1.2
SIX -STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the 41TE Electronic transaxle is
done in six basic steps:
verification of complaint
verification of any related symptoms
symptom analysis
problem isolation
repair of isolated problem
verification of proper operation
2.0
IDENTIFICATION OF
SYSTEM
The 41TE Transmission family can be identified
through a visual inspection. Confirm the presense
of a Solenoid/Pressure Switch Assembly, Transmis-
sion Range Sensor, Input Speed Sensor and Output
Speed Sensor all located on the same side of the
transmission case. Refer to the Service Information
for transmission ID tag descriptions.
3.0
SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1
GENERAL DESCRIPTION
The 41TE electronic transaxle is a conventional
transaxle in that it uses hydraulically applied
clutches to shift a planetary gear train. However,
the electronic control system replaces many of the
mechanical and hydraulic components used in con-
ventional transmission valve bodies.
3.2
FUNCTIONAL OPERATION
The 41TE electronic transaxle has a fully adap-
tive control system. The system performs its func-
tions based on continuous real-time sensor feedback
information. The control system automatically
adapts to changes in engine performance and fric-
tion element variations to provide consistent shift
quality. The control system ensures that clutch
operation during upshifting and downshifting is
more responsive without increased harshness.
1
GENERAL INFORMATION
The control module continuously checks for elec-
trical problems, mechanical problems, and some
hydraulic problems. When a problem is sensed, the
control module stores a diagnostic trouble code.
Some of these codes cause the transaxle to go into
Limp-in or?default mode. While in this mode, elec-
trical power is removed from the transaxle, de-
energizing the transmission control relay, and sole-
noid pack. When this happens, the only transaxle
mechanical functions are:
Park and Neutral
Reverse
Second Gear
No upshifts or downshifts are possible. The posi-
tion of the manual valve alone allows the three
ranges that are available. Although vehicle perfor-
mance is seriously degraded while in this mode, it
allows the owner to drive the vehicle in for service.
Once the DRBIII
t is in the Transmission portion
of the diagnostic program, it constantly monitors
the control module to see if the system is in Limp-in
mode. If the transaxle is in Limp-in mode, the
DRBIII
t will flash the red LED.
3.2.1
AUTOSTICK FEATURE (IF
EQUIPPED)
This feature allows the driver to manually shift
the transaxle when the shift lever is moved to the
AutoStick position. When in AutoStick mode, the
instrument cluster displays the current gear.
3.2.2
TRANSMISSION OPERATION AND
SHIFT SCHEDULING AT VARIOUS
OIL TEMPERATURES.
The transmission covered in this manual has
unique shift schedules depending on the tempera-
ture of the transmission oil. The shift schedule is
modified to extend the life of the transmission while
operating under extreme conditions.
The oil temperature is measured with a Temper-
ature Sensor on the 41TE transmission. The Tem-
perature Sensor is an integral component of the
Transmission Range Sensor (TRS). If the Tempera-
ture Sensor is faulty, the transmission will default
to a calculated oil temperature. Oil temperature
will then be calculated through a complex heat
transfer equation using engine coolant tempera-
ture, battery/ambient temperature, and engine off
time. These inputs are received from the PCI bus
periodically and used to initialize the oil tempera-
ture at start up. Once the engine is started, the
control module updates the transmission oil tem-
perature based on torque converter slip speed, ve-
hicle speed, gear, and engine coolant temperature to
determine an estimated oil temperature during
vehicle operation. Vehicles using calculated oil tem-
perature, are reasonably accurate, during normal
operation. However, if a transmission is overfilled, a
transmission oil cooler becomes restricted, or if a
customer drives aggressively in low gear, the calcu-
lated oil temperature will be inaccurate. Conse-
quently the shift schedule selected may be inappro-
priate for the current conditions.
3.3
DIAGNOSTIC TROUBLE CODES
Diagnostic trouble codes (DTC’s) are codes stored
by the PCM (NGC) or TCM (EATX) depending on
application and help diagnose Transmission prob-
lems. They are viewed using the DRBIII
t scan tool.
Always begin by performing a visual inspection of
the wiring, connectors, cooler lines and the trans-
mission. Any obvious wiring problems or leaks
should be repaired prior to performing any diagnos-
tic test procedures. Some engine driveability prob-
lems can be misinterpreted as a transmission prob-
lem. Ensure that the engine is running properly
and no engine DTC’s are present that could cause a
transmission complaint.
If there is a bus communication problem, trouble
codes will not be accessible until the bus problem is
fixed. The DRBIII
t will display an appropriate
message.
Each diagnostic trouble code is diagnosed by
following a specific testing sequence. The diagnostic
test procedures contain step-by-step instructions
for determining the cause of a transmission diag-
nostic trouble code. Possible sources of the code are
checked and eliminated one by one. It is not neces-
sary to perform all of the tests in this book to
diagnose an individual code. These tests are based
on the problem being present at the time that the
test is run.
All testing should be done with a fully charged
battery.
If the control module records a DTC that will
adversely affect vehicle emissions, it will request
(via the communication bus) that the PCM illumi-
nate the Malfunction Indicator Lamp (MIL). Al-
though these DTC’s will be stored immediately as a
1 trip failure, it may take up to five minutes of
accumulated trouble confirmation set the DTC and
illuminate the MIL. Three consecutive successful
OBDII (EURO STAGE III OBD) trips or clearing
the DTC’s with a diagnostic tool (DRBIII
t or equiv-
alent) is required to extinguish the MIL. When the
Transmission Control system requests that the
PCM illuminate the MIL, the PCM sets a DTC
P0700 ($89) to alert the technician that there are
DTC’s in the Transmission Control System. You
must also erase the DTC P0700 in the PCM, in
order to extinguish the MIL.
2
GENERAL INFORMATION
3.3.1
HARD CODE
Any Diagnostic Trouble Code (DTC) that is set
whenever the system or component is monitored is
a HARD code. This means that the problem is there
every time the Transmission Control System checks
that system or component. Some codes will set
immediately at start up and others will require a
road test under specific conditions. It must be
determined if a code is repeatable (Hard) or inter-
mittent before attempting diagnosis.
3.3.2
ONE TRIP FAILURES
A One Trip Failure, when read from the Trans-
mission Control System, is a hard OBDII (EURO
STAGE III OBD) code that has not matured for the
full 5 minutes to a hard fault. This applies to codes
that will only set after 5 minutes of substituted gear
operation.
3.3.3
INTERMITTENT CODE
A diagnostic trouble code that is not there every
time the Transmission Control System checks the
circuit or function is an a intermittent code. Some
intermittent codes are caused by wiring or connec-
tor problems. However intermittent gear ratio
codes are usually caused by intermittent hydraulic
seal leakage in the clutch and/or accumulator cir-
cuits. Problems that come and go like this are the
most difficult to diagnose, they must be looked for
under the specific conditions that cause them.
3.3.4
STARTS SINCE SET COUNTER
For the most recent code, the Starts Since Set
counter counts the number of times the vehicle has
started since it was last set. The counter will count
up to 255 starts. Note that this code only applies to
the last or most recent code set.
When there are no diagnostic trouble codes stored
in memory, the DRBIII
t will display NO DTC’S
PRESENT and the reset counter will show
‘‘STARTS SINCE CLEAR = XXX’’
The number of starts helps determine if the
diagnostic trouble code is hard or intermittent.
– If the count is less than 3, the code is usually a
hard code.
– If the count is greater than 3, it is considered
an intermittent code. This means that the
engine has been started most of the time
without the code recurring.
3.3.5
TROUBLE CODE ERASURE
A Diagnostic trouble code will be cleared from
control module memory if it has not reset for 40
warm-up cycles.
A warm-up cycle is defined as sufficient vehicle
operation such that the coolant temperature has
risen by at least 22°C (40° F) from engine starting
and reaches a minimum temperature of 71°C
(160° F).
The Malfunction Indicator Lamp (MIL) will turn
off after 3 good trips or when the DTC’s are cleared
from the control module.
3.3.6
QUICK LEARN
The Quick Learn function customizes adaptive
parameters of the control module to the transmis-
sion characteristics of a vehicle. This gives the
customer improved ‘‘as received’’ shift quality com-
pared to the initial parameters stored in the control
module.
Notes about Quick Learn Features
The nature of the Quick Learn function requires
that certain features must be taken into consider-
ation.
> Quick Learn should generally not be used as a
repair procedure unless directed by a repair or
diagnostic procedure. If the transmission sys-
tem is exhibiting a problem that you think is
caused by an invalid CVI, you should try to
relearn the value by performing the appropri-
ate driving maneuvers. In most cases, if Quick
Learn makes a vehicle shift better, the vehicle
will return with the same problem.
> Before performing Quick Learn, it is impera-
tive that the vehicle be shifted into OD with
the engine running and the oil level set to the
correct level. This step will purge air from the
clutch circuits to prevent erroneous clutch
volume values, which could cause poor initial
shift quality.
> If a new control module is installed on a
vehicle with a HOT engine, Quick Learn will
cause the control module to report a cold
calculated oil temperature. This requires
monitoring the calculated oil temperature us-
ing the DRBIII
t. If the temperature is below
15 C (60° F) , the transmission must be run at
idle or driven in gear until the temperature
goes above 15 C (60° F). If the temperature is
above 93C (200° F), the transmission must
cool to below 93 C (200° F).
> First gear is engaged in overdrive after Quick
Learn is completed. Place the vehicle in park
after performing Quick Learn.
The Quick Learn function should be performed:
– Upon installation of a new service control
module
– After replacement or rebuild of internal trans-
mission components or the torque converter
– If one or more of the clutch volumes indexes
(CVI’s) contain skewed readings because of
abnormal conditions.
3
GENERAL INFORMATION
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