Dodge ZB 2005 Service Manual page 1122

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 recommendations below when
choosing your diagnostic path.
1. First make sure the DRBIII is communicating
with the appropriate modules; i.e., if the
DRBIII displays a ''No Response'' condition, you
must diagnose this first before proceeding.
2. Read DTCs (diagnostic trouble codes) with the
DRBIII .
3. If no DTCs are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, 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 2005
ZB/SRT-10.
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
GENERAL INFORMATION
•
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
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
The on-board OBDII diagnostics incorporated
with the PCM controller are intended to assist the
field technician in repairing vehicle problems by the
quickest means.
3.2 FUNCTION OPERATION
3.2.1 FUEL CONTROL
The PCM controls the air/fuel ratio of the engine
by varying fuel injector-on time. Mass air flow is
calculated by the speed density method using en-
gine speed and manifold absolute pressure (IAT is a
modifier in Speed Density).
Different fuel calculation strategies are used de-
pending on the operational state of the engine.
During crank mode, a prime shot fuel pulse is
delivered followed by fuel pulses determined by a
crank time strategy. Cold engine operation is deter-
mined via an open loop strategy until the O2
sensors have reached operating temperature. At
this point, the strategy enters a closed loop mode
where fuel requirements are based upon the state of
the O2 sensors, engine speed, MAP, throttle posi-
tion, air temperature, battery voltage, and coolant
temperature.
3.2.2 ON-BOARD DIAGNOSTICS
The PCM has been programmed to monitor any
circuit or system that has an effect on vehicle
emissions, or is used by the PCM to determine the
proper functionality of these systems. This monitor-
ing is called ''on-board diagnosis.''
Certain criteria or, ''arming conditions'', must be
met before a trouble code will be entered into the
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