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What Are Auto Diagnostic Tests and Are They Reliable?

February 14, 2022 by Denver Express Car Care

When some problems arise, you can visually see the issue. If a tire is flat, you patch it. 

Other problems are more difficult to diagnose. You know your car isn’t running correctly. You know there’s a problem deep within the systems. But where?

Luckily, we have auto diagnostic tests to help pinpoint where the problem is. How reliable are auto diagnostic tests?

The history of auto diagnostic tests

Diagnostic tests are a relatively new concept in the automotive industry. Over the past two decades, the industry grew as electronics were introduced and used just as frequently as mechanics. 

The 1990s are considered the start of automotive diagnostics, as electrical structures were introduced into the complexities of car manufacturing. As computer chips became readily available and we moved to higher technological advances, vehicles changed their structures and relied more on sensors.  

These sensors made it easier to locate a problem. Vehicles converted into a digital piece of technology that could be monitored and tested periodically to ensure everything is working correctly. 

Running an auto diagnostic test from time to time helps keep your car safe and operating correctly. For a technician, it’s no longer guesswork when you bring the car in. Trouble codes tell them where a problem originates. Note – the code refers to where the problem lies, not necessarily what the problem is. This is where training and education come into play, where a mechanic uses their knowledge base to get to the root of the problem. 

What Are Auto Diagnostic Tests and Are They Reliable?

What parts can be tested?

Today’s diagnostic tests can reveal issues in all the vehicle’s major systems. 

  • Engine
  • Exhaust system
  • Brakes
  • Transmission
  • Fuel system

Diagnostic tests are designed to ensure your vehicle is running at optimal levels. It diagnoses:

  • Problems with the engine
  • Issues with the transmission
  • Responsiveness
  • Braking issues
  • Potential contamination or faults with the exhaust systems
  • Wear, tear, or breakage with major components

Drivers often have a misconception about what codes on their dashboards are telling them. If the check engine light turns on, they may attempt to pinpoint the problem by looking up the code being referred to. But this is only a starting point. This is where human experience takes over and gets to the root of the problem. 

What auto diagnostic testing is advantageous 

Technically, scheduling an auto diagnostic test isn’t a “needed” service. It’s not something you plan regularly as you would an oil change. 

Diagnostic testing usually comes into play when you start having trouble with your car. Suppose you notice a problem with performance, or a dashboard light suddenly turns on. In that case, a diagnostic test can help pinpoint where it originates, giving mechanics the ability to move right to the problem. 

This eliminates guesswork, and fixing by trial and error. It gets you in and out faster, and gives you better assurance that the original problem is fixed. 

The reliability of an auto diagnostic test

Depending on the age of your vehicle, you may be familiar with guessing at what a problem is. 

Before technology moved into the way a car functions, many of the most common issues were solved through human knowledge. But sometimes, the most challenging problems could take time to diagnose, as the output of the problem might not match what’s truly wrong. 

This meant a driver may have brought the vehicle back in multiple times trying to get to the heart of the problem. 

That’s wasted time, energy, and effort for all parties involved. 

Take smoke coming from the tailpipe as an example. Smoke coming from the tailpipe is a sign of a problem with the engine. But it could be triggered by several different things. 

It might be water vapor that’s built up inside the exhaust system, burning off as you start the car. 

It might be the fuel/air mixture is too rich, and isn’t combusting correctly. 

It might mean oil is burning inside the combustion chamber due to leaky valves or bad piston rings. 

Or it could be a sign coolant is burning in the engine, signaling it may be a blown head gasket, which could lead to the engine overheating.

A mechanic may recognize the signals and fix one issue. But if it’s multiple problems, one may be overlooked, especially if it’s a minor problem. 

A diagnostic test can pinpoint that and lead to fixing the problem before it escalates. 

Accuracy is important

Years ago, cars were more mechanical by nature. Systems were more straightforward, meaning getting to the root cause was easier for a mechanic to perform. 

That hasn’t changed. Some problems are easy to diagnose. A mechanic may see the issue frequently, and know exactly how to fix it. 

But today’s vehicles aren’t just mechanical. They are a blend of mechanics and technology, designed for precise calibration to ensure efficiency and ease at the same time. 

Compare it to a doctor’s visit. You go in with a complaint, a particular weakness or spot that’s troubling you. A doctor will ask questions, gather information, and order tests. These are essentially diagnostic tests. The doctor may have an idea of what’s wrong, but a diagnostic test confirms it, and rules out other causes. 

The same works for your vehicle. 

A mechanic may suspect what’s wrong. A diagnostic test confirms it. And ensures there aren’t other trouble areas that may be causing problems. 

Is it time for an auto diagnostic test?

If you’ve noticed a problem with one of the major systems, a diagnostic test may aid in getting to the root cause. Before you bring it in, gather as much information as possible:

  • What is the problem?
  • When does it occur?
  • What circumstances surround the most noticeable characteristics?
  • Is there a noise? Is it constant or inconsistent?
  • Have you noticed other issues?
  • Have you tried to fix it yourself?

The more information you bring in with you, the easier it will be for our technicians to figure out what’s wrong. 

Call us today and schedule your appointment. We’re here to help you get back on the road again. 

Filed Under: Engine Tagged With: Reliable Auto Diagnostic Tests

Express Car Care
4200 E. Evans Ave. Denver, CO (map)
Phone: (303) 691-2760
Located just southeast of the Colorado Light Rail station

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