Preface This manual provides a step-by-step approach for diagnosing drivability, emission and powertrain control system symptoms. Before beginning diagnosis, it may be helpful to reference any Technical Service Bulletins (TSBs) or On-line Automotive Service Information System (OASIS) information when this is available. Note: For Villager and 7.3L diesel, go to the VILLAGER or 7.3L DIESEL tab in this manual. This manual is used in conjunction with the Body, Chassis, Electrical, Powertrain Workshop Manuals and the Wiring Diagram Manuals. The Workshop Manuals are used to provide additional diagnostics when directed by this manual. The Workshop Manuals are also used for component removal and replacement information. Refer to the Wiring Diagram Manuals for vehicle specific wiring information and component, connector and splice location. The following is a description of the information contained in each section of this manual. Section 1: Description And Operation This section contains description and operation information on powertrain control systems and components. This section is designed to give the technician a general knowledge of the powertrain control system. It should be used when general information about the powertrain control system is desired, and is rarely referenced from other sections of the manual. Section 2: Diagnostic Methods The Diagnostic Methods section contains information on specific diagnostic tasks that are used during diagnosis. Descriptions of specific diagnostic methods are included, as well as detailed instructions on how to access or perform the tasks. This section provides the technician with step-by-step instructions for performing routine diagnostic tasks. Section 3: Symptom Charts All diagnosis begins in Section 3 with Step 1: PCM Quick Test. If the PCM Quick Test is completed and no DTCs are received, the technician may be directed to Step 2: No DTCs Present Symptom Chart Index (refer to Section 3 for details). The No DTCs Present Symptom Chart Index contains the list of symptoms addressed in this manual, and will send the technician to the appropriate Step 3: No DTCs Present Symptom Chart. If no PCM DTCs are present and the vehicle symptom is not listed in the Step 2: No DTCs Present Symptom Chart Index, the technician should go the appropriate Workshop Manual to continue diagnosis. Section 4: Powertrain DTC Charts and Description Section 4 contains the Powertrain Diagnostic Trouble Code (DTC) ‘‘Go To’’ Charts. These charts will be referenced if a DTC is received in Section 3. Also included in this section are the Powertrain DTC descriptions and list of possible causes. Section 5: Pinpoint Tests All pinpoint tests are included in Section 5. Never enter a Pinpoint Test unless directed there. When directed to a Pinpoint Test, always read the information and look at the schematic included at the beginning of the Pinpoint Test. Section 6: Reference Values Section 6 contains the ‘‘Typical Diagnostic Reference Values’’ charts. The technician will be directed to these charts from Pinpoint Test Z in Section 5.