Important
New for TJ, the Powertrain Control Module and Transmission Control Module have been
combined into single control module on all vehicles equipped with a 2.4L and 4.0L engines. This
new module is the Next Generation Controller (NGC). New Diagnostics procedures along with
new DTC’s are two of the changes you will see which reflect the new combined module
technology. The NGC modules will have four color coded connectors C1/A through C4/D,
(C1-BLK, C2-ORANGE, C3-WHITE, C4-GREEN). Each PCM connector has 38 pins. Two new tools
were introduced to help diagnose and repair the new PCM (NGC) terminals and harness
connectors. The Miller #3638 terminal removal pick must be used to release the connector
terminals, or harness and connector damage will occur. Also, the Miller #8815 Pin Out Box was
introduced. You must use the Miller #8815 tool instead of probing the PCM terminals, or harness
and connector damage will occur. There is also a new Verification test and module replacement
procedure for the new PCM.
1.0
INTRODUCTION
The procedures contained in this manual include
specifications, instructions, and graphics needed to
diagnose the PCM Powertrain System. The diag-
nostics in this manual are based on the failure
condition or symptom being present at the
time of diagnosis. Please follow the recommenda-
tions below when choosing your diagnostic path.
1. First make sure the DRBIII
t is communicating
with the appropriate modules; i.e., if the DRBIII
t
displays a
9No Response9 condition, you must diag-
nose this first before proceeding.
2. Read DTCs (diagnostic trouble codes) with the
DRBIII
t.
3. If no DTCs are present, identify the customer
complaint.
4. Once the DTC or customer complaint is iden-
tified, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0.
All connector pinouts are in Section 9.0. All system
schematic diagrams are in Section 10.0. All charts
and graphs are in section 11.0.
An * placed before the symptom description indi-
cates a customer complaint.
When repairs are required, refer to the appropri-
ate service manual for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; current systems
may be enhanced. READ THIS MANUAL BEFORE
TRYING TO DIAGNOSE A VEHICLE DTC. It is
recommended that you review the entire manual to
become familiar with all new and enhanced diag-
nostic procedures.
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
This diagnostic procedure manual covers Power-
train, Transmission, and Transfer Case diagnostics
for 2005 TJ vehicles equipped with the Next Gen-
eration Control Module (NGC).
1.2
SIX-STEP TROUBLE SHOOTING
PROCEDURE
Diagnosis of the Powertrain Control Module
(PCM) 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 Powertrain Control Module (PCM) monitors
and controls:
•
fuel system
•
ignition system
•
charging system
•
speed control system
•
The NGC control module is used on the 2.4L and
4.0L engines with an automatic or manual trans-
mission.
•
The 42RLE transmission can be identified by
confirming a Solenoid/Pressure Switch Assembly
located on the right side of the transmission, The
Transmission Range Sensor, Input Speed Sensor
and Output Speed Sensor are located on the left
side of the transmission. Refer to the Service
Information for transmission ID tag descriptions.
1
GENERAL INFORMATION