How to Use This Section

HOW TO USE THIS SECTION


Diagnosis of faults is done in three basic steps:

1. Visual inspection

- A careful and thorough visual inspection may quickly identify the cause of a malfunction and eliminate the need for additional diagnostic procedures.

- Diagnosis of vehicle faults always starts with the visual inspection. If the fault is not resolved by the visual inspection, perform the diagnostic test(s).

2. Diagnostic tests

- Each specific fault is diagnosed by following a specific testing sequence. It is not necessary to perform all of the tests in this book to diagnose an individual fault.

- Always begin diagnostic testing with Test 1A. This will direct you to the specific test(s) that must be performed in response to the specific vehicle fault.

3. Verification test - A verification of system operation must always be performed to ensure that the system is operating normally after the cause of a fault has been found and repaired.

All of the information in this manual has been specifically included to assist you to find the cause of a vehicle fault.

Helpful information Section

- The helpful Information section contains all of the basic information you will need to perform diagnostic tests using the DRBII.

- Begin by reading the Helpful Information section carefully and thoroughly.

- Included in the Helpful Information section are several "HELP" subjects (see the Table of Contents). These provide important basic information about the DRBII, components, connectors, and safety. Reference is made to the HELP's within a test procedure when the information is required for correct performance of the test. NOTE: Be sure to read HELP 5
- Safety Instructions very carefully before performing the test procedures.

Diagnostic Test Procedures

Finding the cause of a vehicle fault is not always easy or quick. However, the diagnostic test procedures in this manual have been designed to lead you through the steps necessary to find the cause of a vehicle fault as easily and quickly as possible.

- The diagnostic test procedures contain step by step instructions for how to determine the cause of a vehicle fault. Possible sources of the fault are checked and eliminated one by one.

- The diagnostic tests include a schematic of the electrical circuitry for the system, and illustrations of the system components and connectors to clarify the test steps.

- For instructions on performing test procedures, see "Diagnostic Test Procedures" later in this section.

To successfully perform diagnostic testing, use the information and follow the procedures as presented in this book.