Car Shakes - 2016 Sonata

Now and then my 2016 Sonata Hybrid will start shaking. The first time it happened, I was on the highway and it felt like I was driving over (mild) speed bumps (but I wasn’t). When it happens, which isn’t frequent, it usually happens on the highway less then 10 minutes after entering and it lasts less than 30 seconds (but feels like forever). The check engine light will turn on, but when I get the check engine light’s records checked (which I’ve done 3 separate times), they never see any record of it coming on. Admittedly, besides getting oil changes, I don’t get any regular maintenance done. Any thoughts? Any particular things I should have my mechanic look for?

Look for a misfire. Have your car’s error codes scanned with a proper scan tool. If the check engine light was set, it will be stored, at least for a while.

If the car has lots of miles, plan on new sparkplugs and maybe a coil or 2.

Likely an intermittent coil failure, those cars have a known coil problem:

16-01-003-1 Hyundai Technical Service Bulletin (tsbsearch.com)

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When a misfire (e.g. intermittent coil failure) turns on the CEL, a diagnostic code will be stored in the computer’s "pending- " or “current-code” memory. If the misfire self-corrects, the code might be moved from there to the “history” section of the memory. Ask your shop to check all three sections for diagnostic codes. I expect at least one of the three memory sections will have a stored code starting with “p03”

Just to be clear, is this an indication of a manufacturer defect that Hyundai should be fixing for free or is this just a part that normally goes bad over time that I should be responsible for replacing?

It’s out of warranty. The technical service bulletin is a technical tip for the mechanic to narrow down the possible causes for your problem. Expect to pay for diagnosis, parts, and labor to fix then problem. The good news is that the diagnostic fee could be low since the TSB points to the usual cause.

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No, but make sure the spark plugs are serviced at the recommended intervals. If the spark plug gap grows too wide, the computer may correspondingly increase the spark voltage, and over time the higher voltage can overheat & damage the coil.

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Thank you. What does “TSB” mean?

TECHNICAL SERVICE BULLETIN

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Thank you.

I saw a video showing how to change the spark plugs in my 2016 Sonata Hybrid. The video pretty much implies that you unscrew the old ones, take them out and then screw in the new ones. They did use a tool specially made for this. Is that all there is to it? You don’t have to make any kind of special adjustments? Are there any common mistakes that amateurs make when doing this? Is there anything in particular I should look for when buying the spark plugs?

That special tool is a spark plug socket.

There can be issues for newbies… stripping the threads, damaging the coils, breaking connectors, cracking a plug…

You need to buy the proper spark plug for your car… and not from Amazon. Too many fakes on there.

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