MWM Exclusive: Understanding & Applying Diagnostic Grammar

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I recently attended a local training seminar in which we discussed and worked on an LG top load washer. The topic of error codes and how to diagnose them arose, so we chose the LE error as the code we would begin with. First, we opened up the LG Tech Assist website and began going through the flow chart to try to determine the cause of the code. After about 10 minutes of the group being unable to agree on the cause, it occurred to me that no one had asked the most obvious question, and this lack of basic inquiry made it much more difficult to approach the problem in a clear, analytical way.

The most obvious question, the one upon which all further diagnosis and discussion should be based, is, What does LE stand for? This is what I’d like to address—not the error code itself, but the foundation of the diagnostic process. That foundation is information, which includes terminology, symbols, and specifications, all of which can be classified as “grammar.”

In a recent article I discussed something called the Trivium Method, what it is, and how to apply it to learn any subject. This word has been used in the past to define those aspects of the seven liberal arts that pertain to the mind: grammar, logic, and rhetoric.

In part one of this three-part series I’d like to expand on this concept and focus on grammar, the foundation of everything else. We commonly understand grammar as it’s applied to language, and traditionally this is how it has been applied under Trivium in a classical education. Grammar, as it’s used in this article, pertains to the fundamental data of any subject, such as terms, symbols and

other elemental information which underlies every subject. Without first understanding the terms and symbols of a given subject and what they represent, it’s impossible to truly understand how and why they can work together.

Every service manual begins with an explanation of terms and symbols used in the manual, as well as a list of specifications. This is the grammar of the appliance in question. This information is doubly necessary because technical lexicons can be extensive and quite different than standard language, making comprehension based on context much more difficult. Unlike standard language, context will often be of no help. That is to say, the meaning of “LE” cannot be gleaned by using it in a sentence.

What would be the way in which to apply this method to a diagnosis of the above error code? The first step is to define the term LE, which means locked motor error. Next, define motor. In this case it means rotor, stator, and hall sensor. Then define rotor, stator and hall sensor, and continue defining all subsequent terms until each technical term is understood. How can we understand why a hall sensor can cause an LE error if we don’t first understand what a hall sensor is and how it operates? Once each technical term is clearly defined, the specifications of each term that describes a component can be understood, such as resistance of the windings in the stator, voltage and resistance specifications of the hall sensor, etc.

This procedure should also be applied to the symbols on schematics and wiring diagrams. Only a complete understanding of the grammar of the machine will enable a technician to accurately understand the logic of the error, which is the “why.” The “why” cannot be truly understood until comprehension of the “what” is achieved. This process can be repeated in depth to any level of intricacy one wishes to take it to. The physics of the rotor and stator can be delved into. The hall effect, which is what the hall sensor is measuring, can be looked at in more detail, and on and on ad infinitum.

In this way, literally any subject—machine or concept—can be understood relatively quickly and accurately. The grammar of any subject is the key to developing a firm understanding of the whole concept, and it must be completed first. Not doing so seems to be a common mistake in making a

diagnosis. When a technician skips grammar and attempts to understand logic from the start, the conclusion will be, at best, a correct guess. At worst, a completely incorrect diagnosis and possibly a costly mistake. Correct application of this method will allow any technician to become a master diagnostician, greatly increase their completed job rate, and reduce return trips.

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