How To Use This Information

Diagnosis of a DRBII-to-vehicle communication problem is done in three basic steps:

1. Identification of the system, vehicle, and problem
- TEST 1A, the testing table of contents, is there in order to provide quick access to the specific test procedure that will correct your problem. Pay close attention to the system (such as general, body, engine, or chassis) you select, as well as the vehicle body type and the problem.

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.