Definition
Fault isolation is the process of narrowing a detected problem (an alarm, an abnormal reading, a customer complaint) down to the specific system, subsystem, or component actually responsible, using systematic testing to eliminate alternatives. It answers "where" the problem is located, as a precursor to the "how do I fix it" step of troubleshooting.
Key facts
- Narrows a problem to a specific responsible part of the system, answering "where," not "why" (failure cause) or "how to fix" (troubleshooting steps).
- Uses systematic elimination (testing subsystems or swapping known-good components) rather than guessing.
- A precursor step within the broader troubleshooting activity, not a synonym for it.
- Effective fault isolation reduces unnecessary part replacement by confirming the actual responsible component before repair.
What does Fault isolation reveal about failures?
Fault isolation takes a general symptom (an alarm, unexpected behavior, a customer-reported issue) and systematically narrows the search to the specific system, module, or component responsible, typically by testing subsystems individually or substituting known-good parts to eliminate alternatives.
How do teams use Fault isolation in failure analysis?
Diagnostic reasoning is the underlying thought process of forming and testing explanations. Fault isolation is a specific application of that reasoning aimed at narrowing down location. Troubleshooting is the broader end-to-end activity, which includes fault isolation as one step, followed by the actual corrective action and verification.
FAQ
Frequently asked questions
How is a fault narrowed down to the affected part of a system?
Through fault isolation: systematically testing subsystems or components to eliminate alternatives until the specific one responsible for the detected symptom is identified, ahead of the actual repair.
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