Troubleshooter: Dealing with those dreaded intermittent issues

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For all the advancements in automotive design, engineering, production and technology, many consumers still walk away from their service providers miffed, because their concern couldn’t be addressed due to its intermittent nature.

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It’s usually the time when vehicle owners get educated on the shortcomings of diagnostic systems and support for their rides. Intermittent symptoms come in all shapes and sizes, and how to correctly handle things varies from one type to another. Let’s start with the most common, of an appearing and then disappearing “check engine” warning light.

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Troubleshooter: Dealing with those dreaded intermittent issues Back to video

That unwanted light

You’ve contacted your shop and made an appointment. But the day before your scheduled visit, the light suddenly disappears, and everything seems fine. So what do you do? For pretty much anything built since the mid-1990s, the onboard computers have the ability to store inactive or historic codes, so your tech should be able to figure things out, right?

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Wrong. For every code that can turn on a warning light, there are pages of diagnostic tests, which usually involve checking wiring harnesses and components for proper electrical values and operations. The problem with running any of these tests on a vehicle without an active warning light or code(s) is that it’s highly unlikely any faults will show up.

That’s because any possible cause will now test within normal limits. About the only hope of finding something wrong in a case like this is if the automaker has issued a technical bulletin on the specific code(s) with specific repair details, or if it’s an extremely common occurrence with your specific make and model, and your tech is experienced enough to pinpoint the cause. Other than that, you’ll likely have to wait until the warning light stays on or until other symptoms crop up, such as rough running, lack of power, improper shifts, etc.

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The noise, the noise, the noise—

If there’s any statement that’s bound to frustrate your service consultant more than any other, it has to be, “My car’s making a funny noise, and I’m not sure where it’s coming from.” Or then the customer adds, “Oh, and it doesn’t do it all the time, and in fact, I didn’t hear it on the way over here today.”

If the noise isn’t predictable and your tech can’t duplicate it, you’re wasting both your time and the shop’s. Instead, make notes, such as where the noise appears to be coming from, under what driving and road conditions, and if it’s connected to any specific operations, such as cornering, braking, or acceleration. Park somewhere and write down your notes, or use the recording feature on your smartphone. If the noise is loud enough, get your passenger to use your phone to capture it, so you can play it back for your tech.

Remember, there is a major difference between a noise you can hear , and a vibration or sensation you can feel. The number of drivers that get this mixed up will surprise you. The best chance you have of getting this rectified on a first visit is to arrange a road-test with a shop employee when you call to make the appointment. Then at least you’ll know you and your shop are on the same page.