2016 Chevrolet Sonic - anybody else having problems?

2016 chevy sonic. check engine light came on. Car alert says issue with emissions system has been detected. Dealer claims not covered and I would have to pay diagnostic fee to determine issue. Second major issue in two months. First it was the AC. Once fixed now this problem. Anyone else having similar issues?

Sounds typical. 3 yr, 36K basic. If you are out of that period, the 5 yr 60K will cover only if it’s the powertrain or an emissions problem. There are many error codes that are not emission related.

You can take it to your local auto parts store and have the codes read.

If the repair is covered under warranty, they are supposed to waive diagnostic fees, but some dealers may not. (One owner I chatted with says he was charged $1100 to diagnose, then zero for the warranty repair… but he’s fuzzy on details.) Try to get (in writing) what will be charged and what conditions will refund your money. Be aware, if they get your credit card, the fee can be open ended, but that’s no different than an independent shop (except they’ll charge for the repair as well).

Sigh…just another reason why Chevy is falling behind in the car market…used to love them, but now my household is Chevyless.
See if you can get the codes read at an auto parts store. If you get lucky enough to find someone to help that knows a little, they may be able to help (but don’t take their word as gospel!). With the fault codes, some online tools can provide some guidance on potential problems; put in “Chevy Sonic 2016 (insert fault code)”. Outside of something simple, I probably wouldn’t tackle myself, but it might point you in a direction, especially if it might be expensive.
I’ve heard that something as simple as a faulty gas cap can cause an emission systems fault, so this may not be a big deal.
Don’t feel obligated to use the dealer’s service department. I’m sure a number of shops can handle Chevys.

Your car has an 8 year/80k mile Emissions Warranty that covers certain components.
You need to have the problem diagnosed in order to determine exactly which component(s) is/are at fault. If any of them are covered by that warranty, then you shouldn’t have to pay anything for the repair.

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Did the dealer receipt list the codes the OBDII system tripped? If so, list them here with any problems you may have noticed. If you don’t have the codes, get them read at an auto parts store for free and post them here, as suggested above.

Wow! If that’s how the Chevy dealers work (telling you that’s not a warranty issue when it might be), then they deserve to lose market share. So how do you handle a diagnostic fee for something that MIGHT be a warranty item? You pay if it isn’t, you don’t if it is a warranty item? Seems like a system with lots of problems.

The only emission components warranted for 8 years/80,000 miles are the catalytic converter(s) and engine control computers.

Everything else is warranted for 2 years/24,000 miles.


Is there anything left on 3/36 bumper to bumper warranty? I know when dealing with my sister’s Cruze I has to be pretty heavy handed about getting stuff covered. 1-800-222-1020 is the number for Chevy customer assistance. I had quite a few rounds with them but ultimately prevailed. They insisted that cam phaser seals weren’t covered by powertrain warranty, even though the warranty said seals were covered. Also, never hesitate to engage Chevrolet on social media also with your problem. Sometimes public shaming helps.

Thank you everyone for your responses. I really appreciate all the advice and knowledge! I am going to take it to a mechanic and see what the codes are. This will help me determine if it is covered by what they say is limited warranty. I will say this Chevy is definitely not what it use to be. This car was purchased brand new in 2016. I have kept the maintenance up as well. I called GM and they’re telling me I would have to pay for the diagnostic as well :rage:. I will not be buying another Chevy. I will keep you all posted.

Thanks again for all your help


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I could see paying diagnostic up front if they agree to wave it if its a warranty repair.

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Do you mean the mileage? If so no I am over 36,000 miles. Mileage is approximately 60,000. Miles are highway. Purchased for my college kid.

I believe they are saying I have limited power train warranty. I was thinking well that should be covered since under the hood.

The date of purchase and the current mileage determine if the basic warranty has expired.

Personally, I don’t think you should get all wound up over this. The car is likely 3.5 to 4 years old with ? miles. A car is a collection of used parts; any of which can fail at any point.

While you’re understandably unhappy with your Chevy, someone across town is unhappy with their (fill in the blank).

You have not stated what codes or codes are present. This could possibly lead to issues of maintenance. The car has 60k miles on it. The schedule shows air filter should have been replaced already and the spark plugs are currently due.
All depending, has the college kid driving this been overfilling the fuel tank when gassing up? As with most kids, I’m sure if asked and if they thought there was a problem they would likely deny doing it.


I am going to take the car to a mechanic to determine the codes and go from there. I was thinking maybe she put some bad gas in the car and it’s affecting the emission system.

You can’t overfill the fuel tank on today’s vehicles. The EPA demanded that car makers prevent owners from doing that where it could damaged the charcoal canister. So they installed an overfill check valve.

It also acts as a rollover check valve.


Bad gas is really rare these days. You are out of warranty and have 60000 miles and just because it is a GM product the same rules apply to any brand out of warranty. You can not expect a mechanic to work for free to find out what is wrong with the vehicle.

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I never said I wanted anyone to work for free. What I did say is that if I still have the power train warranty of which I do, I do not and should not have to pay for them to fix the issue.

If you had a Honda or Toyota, their corporate customer service people would tell you the same thing. Even if there isn’t a separate line item for diagnostics, it’s built into the cost of the service you receive. The same will be true for an independent shop if you go there.

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A power-train warranty and an emission warranty are two totally separate things.