Diagnostic Guidelines

Follow the below steps as guidelines for using the Test Procedure:
1. Start from test number 1 of the catagory you are using. Starting from any other point will give you incorrect results.
2. Always perform the diagnostic sequence in each catagory to determine what test is to be performed.
3. Only perform the steps which are required. Performing all steps will give incorrect results.
4. Test have reminders, these are to inform you that previous instructions are still required.
5. 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.
6. When performing the cold test, the engine must not be started for at least 7 hours.
7. When performing the warm test, the engine must be at normal operating temperature.
8. The vehicle must have a fully charged battery.
9. When checking for voltage or continuity at the engine control module 60-way and 14-way connectors use the terminal side of the connector not the wire side. Probing the wire side will give inaccurate results, damage the female terminals, and cause failures.
10. Use extreme care when making electrical tests and when disconnecting and re-connecting connectors to prevent accidental grounding, shorting or energizing terminals which are connected to the module. Such mistakes can possibly damage the module and also can cause a second fault that could make diagnosing the original problem more difficult.
11. Under no circumstances should a test light be used in place of a voltmeter because damage to electronic components may occur.
12. If the procedure requires you to crank the engine with the coil wire disconnected, make sure that it is grounded or held a quarter of an inch away from ground to allow sparking. Failure to do this will erase all fault codes and possibly damage the module.
13. Avoid long checks for fuel flow from the injector to prevent flooding or hydrostatic damage to the engine.
14. This is a pressurized fuel supply system. After testing make sure all fittings are restored and torqued before starting the engine. Once the engine is started, check for leaks at all lines that were disconnected.
15. 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.
16. Some tests require the use of a digital or analog voltmeter. Make sure you use the correct one or you may see incorrect results. If a test does not specify the type of voltmeter then either one may be used.