I currently drive a 2020 Elantra I purchased last June.. On Saturday, my check engine light came on, the car ran rough, idled rough, and wants to stall.. Get home turn car off. On Monday I pulled a code with a basic code reader. It indicated one code "P03003" Missfire cylinder #3
Today, I was able to drive the car to the dealership were I purchased the car.. The check engine light was off, and car ran normal.. After 2 hrs, they tell me they can not find any stored codes, so they can not further investigate what happened..How far must the car be driven, in order for the car to store codes? I had it, and I did not clear the code either.. They said any were between 30-300 miles depending on car.. I find this very concerning, because if it happens again, they will not be able to do a thing, especially if they are closed, like on Sat, so I will not be able to bring it straight to them.

 

The right way to solve this problem is to leave the vehicle with the service dept and have them use it until they can produce the problem. They should provide a loaner vehicle while this is going on.

It appears from what you describe, there is a problem involving #3 cyl and when the problem surfaces the vehicle goes into limp mode which means it can be driven to a service facility, but not much else. Whatever is causing the problem is being picked up by the computer and allowed to reset when you turn the key off.

 

The ECU needs to see the problem for two drive cycles before it will turn on the heck engine light.
It will store the code and any information when it happened.
If the battery is disconnected then codes will be lost
If code reader erases or turns off CEL then codes will be lost
If condition clears and driven then possible the ECU self cleared the CEL

Intermittent problems are the hardest to troubleshoot.
However, they eventually turn into hard failures
There are a few things you can do to see ....
Take spark plug out and inspect the plug for fouling, cracks, gap, etc.
If coil over plugs then inspect the coil for spark tracks/misfire
Hopefully they did that at the service dept of the dealership

When was the oil last changed?
Last time you put injector cleaner into gas?
Mark down mileage and date of misfire and record when taken in to dealership
Keep as record. Document with videos, witnesses.
If they can't fix it then maybe you have some other recourse
But, will need proof. Keep records. Call Corporate if issue not fixed.
Squeaky wheel gets the oil

 

The car had it's oil change around 7K miles, it would be the second one... At time of problem the car OD read 9774.. The service center, claimed since they can not find a code, there is nothing to be done.. If it happens again bring it in.. It has not come on since the first time on Saturday.. Battery was not disconnected either. I had asked them if they pulled the coil and spark plug and inspected. They said no, because there was no reason on their end as the car's check engine light was not on.. What I found funny. They said it did show that the light was on for no more than 9 miles.. With that I said, then why did you not do a basic and simple inspection of plug and coil pack.. Thy repeated the same answer. No check engine light on, no need to check...

 

Documentation of this trouble and if they can not fix it then think about lemon law
Make them fix it if it happens again.
Seriously, spending a huge amount of money for the car, the vehicle should not have problems.
Sorry, that is just my feelings. It is also why I won't buy a new car.

 

I'm keeping a eye on it everyday... This is my first Hyundia. I have had a total 5 Kia's. 1) 06 Kia Sportage EX with the 2.7 V6. Traded at 168k miles, never seen the inside of a shop but for routine maintenance. 2) 2011 Kia Forte SX 5 door, purchased with 34k miles totaled by a drunk with 64 k miles.. This one had a few minor issues, but resolved with one trip to the dealer. 3) 2016 Kia Forte LX. Traded at 74 K miles. Again no issues just routine maintenance, never had warranty work, recalls, like my Sportage not even had a check engine light come on.. 4) 2013 Kia Forte SX, traded at 75K miles for a 5) 2020 Kia Forte (Wife's car) with the GT line package.. I have been real happy up until this purchase.. Hopefully it was just a fluke.. But I do have excellent extended warranty.. For $20 a month I have no parts no labor, no diagnostic fee, and no deductible.

 

That is very concerning. The next time your Check Engine Light turns and stays on, you might want to go here. It tells you how to fix the error- all by yourself.

 

If anyone today with a fairly new vehicle thinks they are going to find the problem and repair it too is in for some rude awakening.

Today, just a code is next to useless if the person doesn't have the tools, information, and knowledge handy, to even begin to know where to look for a problem.

Picture your TV set, would you start attempting to repair it ?
With the amount of electronics in today's vehicles , which by the way have more electronics and computer modules in them than the first space ship that went to the moon., You might start with a code which only provides some direction, then you need to know how to examine data stream info from a capable scan tool, then have the tools to get to the area where the problem may be located. The days of fix it yourself are just about gone and there are folks out there that are willing io tackle a problem that they only make worse by replacing good parts with hopefully good parts and creating new problems on the way..
This may sound discouraging, but it is the horrible truth.
Even dealerships are having trouble finding , training and retaining competent people.
Some shops manage to stay up on the latest info and tools required AND it gets very expensive.
We all hope a new vehicle will not have any problems for at least a while anyway. Sometimes we get lucky.

 

I hope you figured out your issue.

I had a 2017 Elantra with the exact same issue. This is a copy and paste from my review after my service with no fix and me trading the car

RE: Hyundai
JD
Justin Demler
To:
Justin Demler
Sat 2021-10-30 9:07 PM




Sent from my Galaxy


-------- Original message --------
From: Justin Demler <justindemler@hotmail.com>
Date: 2021-10-30 2:39 p.m. (GMT-07:00)
To: Justin Demler <justindemler@hotmail.com>
Subject: Hyundai



1. Initial issue, check engine light on, car misfiring, brought into Hyundai next day. Technican could not find stored code, phoned and said nothing was wrong. Showed him ny scan tool and the misfire on 3(did not clear codes). They ended up swapping coil/spark between 2 and 3 cylinder. (Charged for scan)

2. I pick up vehicle that day, drive around the block, misfires and cel comes on. Don't believe it was test drove. Bring it straight back in, they take vehicle, find misfire code on 3, find a TSB for ecm upgrade. They upgrade it, I take vehicle home.

3. Two days of driving and CEL is on and misfires. Book a new appointment. Service writer gives me a work order for new spark plugs, fuel injection cleaning and a plugged air filter. I ask the service writer why they called my air filter, as I replaced it a week earlier, myself a journeyman mechanic myself. He came back and said it was not, in fact, dirty at all. But the technician had written it down on the wrong RO (everything else was on point though). I said I didn't believe it was the spark, as we had swapped the two plugs in a prior appointment and it had not switched the codes, as well as my sparks only had 51000km at the time (lifetime of 95000 miles, from Hyundai website). As this wasn't covered under warranty I had to pay out of pocket and I agreed to have it done, as I have to trust the technicians.

4. I come in the next day and pick up my car, drive it for I believe a day and it misfires worse then ever before and CEL comes on. I bring it in and tell service the issue. They explain that sometimes it will sometimes be rough after a fuel injection cleaning ( a) probably something that should be explained to people, if that's true, b) why wasn't it test driven?). Anyway I had them scan it, no codes, stored or active.

5. I agree to drive it and try to catch a picture of the CEL(not safe). As they need proof that it's still an issue. I drive for a few days and eventually it happens again. I bring it in with a picture of CEL and KMs as proof. I believe this time the coils were replaced. Code was stored and found

6. Picked up car again, drove for a while, same issue, brought it in. No codes again, have picture proof again. I believe this was the time that I was going on vacation and left the car with Hyundai for the 8 days I was gone. I received a message the day I returned saying the car was good, I asked what they fixed and the service writer said nothing, as there was no code and the test drive was good. I asked them to please keep it until it's fixed. They held onto it and eventually Dean was able to get the issue to replicate, misfire on cylinder 3. Intake gasket to be replaced.

7. They called #3 injector and replacereplaced

8. I actually got a loaner car this time. When the Elantra was finished I picked it up. Drove for a while, seemed good, than it happened again. This time I'm video recording and have my personal code reader in my car at all times while driving. Bring it back, no codes.

Again, this is why I appreciated Dean, he believed me and tried to figure out the issue. I told him I have video and pictures of my scan tool with the stored code. They took the car again.

9. Get a phone call and they believe it's the OCV, removed and cleaned. Picked up car and drove for about a week, issue comes up again. Videos again, codes again.

10. Phone into service department because I believe one of the biggest issues is that the ecm is not storing codes. I want to prove to them that I have videos of the engine light coming on and going off. Service advisor tells me he understands but it's impossible to proceed with warranty work without a code, he tells me best case scenario is the engine dynamites as that's an easy diagnosis. I disagree that would be best case, as I don't want to have my engine explode and be stuck with a tow bill and no car and likely no loaner car. As I said I only have 51000km, with the alloted service intervals, this should not be the best resort. I just want my car to work. Service manager phones me and says they are going to order the OCV and replace those.

11. I drive into Hyundai as the code came on again and wanted to show a technician. They get me in ASAP, tech hooks up scan tool, no codes, no codes on my tool, but I had taken a picture of it when it had the code, and it was showing misfire on cylinder 4. I show technician the video I just took, with check engine light on and KM, he says it sounds like it needs a new PCM.