Troubleshooting Guidelines

VERIFY THE COMPLAINT
- Make sure the customer's complaint and the service writer's work order description are understood before starting work.
- Make sure the correct operation of the system is understood. Read the description to verify any aspect of normal system operation.
- Operate the system to see the symptoms. Look for other symptoms that were not reported by the customer, or on the work order, that may be related to the problem.

DETERMINE POSSIBLE CAUSES
Compare the confirmed symptoms to the diagnostic symptom indexes to get to the right diagnosis procedure.

If the confirmed symptoms can not be found on any symptom index, determine other possible causes.
- Analyze the system diagrams and list all possible causes for the problem symptoms.
- Rank all these possible causes in order of probability, based on how much of the system they cover, how likely they are to be the cause, and how easy they will be to check. Be sure to take experience into account. Consider the causes of similar problems seen in the past. The list of causes should be ranked in order from general to specific, from most-likely to least-likely, and from easy-to-check to hard-to-check.

FIND THE PROBLEM
After the symptoms have been confirmed, and probable causes have been identified, the next step is to make step-by-step checks of the suspected system components, junctions, and links in logical order.

Use the diagnostic procedures whenever possible. Follow these procedures carefully to avoid missing an important step in the diagnosis sequence. It might be the skipped step that leads to the solution of the problem.

If the step-by-step procedures is not available to help diagnose the problem, come up with a series of checks based on the ranked list of probable causes. Troubleshooting checks should be made in the order that the list of causes was ranked:
- general to specific
- most-likely to least-likely
- easy-to-check to hard-to-check

REPAIR THE PROBLEM
When the step-by-step troubleshooting checks find a fault, perform the proper repairs. Make sure to fix the root cause of the problem, not just the symptom. Just fixing the symptom, without fixing the root cause, will cause the symptom to eventually return.

VERIFY THE REPAIR
After repairs are made, recheck the operation of the system to confirm that the problem is eliminated.

Make sure to check the system thoroughly.

Sometimes new problems are revealed after repairs have been made.