Diagnostic Strategies

The following are some guidelines in using the Test Procedure:

1. Start from test one of the category you are using. Starting from any other test will give incorrect results.
2. Tests are made up of many steps. Only perform the steps which are required. Performing all steps will give incorrect results.
3. Some steps within a test have reminders. These are to inform you that previous instructions are still required.
4. At the end of each test reconnect all wires and hoses, turn engine off if required, and reinstall any components that were removed for testing.
5. The vehicle being tested must have a fully charged battery, specific gravity 1.220 temperature corrected.
6. To peform the cold test, the engine must not be started for at least 7 hours.
7. To perform the warm test, the engine must be at normal operating temperature.
8. Never use a test light in place of a voltmeter or damage to electronic components may occur.
9. If more than one fault code appears, review the test for multiple code combinations. If one cannot be found, then handle each fault code as a separate failure.