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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The problem was eventually solved by replacing a spark plug and coil. I ended up buying an Autolink al329 OBD2 scanner. Within days it gave me an error code that pinpointed the cause of the problem. My thanks to everyone for their help with this.
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My check engine light came on again a few weeks ago. Using my Autolink al329 OBD2 scanner, I saw the following: “P0266 $7E8 Generic Cylinder 2 Contribution/Balance”. I think the spark plug and coil that was replaced in August came from cylinder 2. Currently, the car appears to be running fine unlike prior to the August repair when it was shaking. Any thoughts?
Pull the plug and inspect it. If it’s clean move the coil to another cylinder and see if the code changes.
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Ask your shop if it makes sense to replace all the spark plugs? Spark plug problems can damage the coils.
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My mechanic looked at it and says that there is decent chance that it is the fuel injector, but he’s not sure. He said that it would be at least $700 parts and labor to replace it and suggested that I have the dealership do a diagnostic so that we can be sure. (Unfortunately, I think the dealership charges around $200 for just the diagnostic.) I’m interested hearing if anyone has any thoughts about this.
Are you still getting a misfire diagnostic code? It might be possible to swap the injectors around to see if the symptom follows the swap or not.
I appreciate the response. The mechanic says that it’s a ton of work (and thus expensive) to access the fuel injectors because of the location.
This is what my OBD2 scanner gave me: P0266 $7E8 Generic Cylinder 2 Contribution/Balance
My car is still under the powertrain warranty and, according to google (which isn’t always right), the fuel injector is part of the powertrain. Is google correct?