For context I have a 2018 Sonata 2.0t that started flashing warning lights on my way home last night. Last visit to the dealership was less than a month ago and service providers said everything was in great condition. I figured this might be an alternator malfunction. Does anyone know if fixing this is covered at all by the 100k warranty or am I out a few hundred bucks coming up to get this fixed? Or if any of you know what other issue this could have came from?
If the engine light is flashing and not steady then it’s an “oh shit” light. If it was the alternator, the battery would be flat by now so I doubt it’s that. That being said if it is powertrain related, it should be covered.
@Zen
definitely the ‘oh shit’ light then, the engine light, BSM light, and traction control light were flashing like crazy, then my RPMs, speedometer, gas, and engine temperature light were going up and down like crazy too. Never have experienced it before while driving so fingers crossed this is covered. Thank you!
@Hale
We had this problem with a mazda, and it turned out the fuse box cables were basically only connected by a string before fully breaking. Worth a look.
@Hale
Doesn’t always mean you’re completely screwed. Could be a misfire. Swap coils, and sparks. Try again, and if it keeps flashing you’re screwed. Had this happen with my 07 santa fe. It had a misfire. That was the best case scenario though. Super cheap to fix.
@Hale
Definitely sounds like an electrical problem. That’s what my Kona did with a low battery - lights and gauges went crazy. I wasn’t driving at the time (too dead to start, just made the instrument cluster go crazy) but I’m sure a dying alternator would have the same effect. Probably wouldn’t cover the alternator under warranty but worth asking. Auto parts chains will test your alternator and battery for free, and they may install a new alternator with no labor cost, if warranty doesn’t cover you.
@Hale
Did the battery light come on when the engine was still running? Might be a bad alternator that caused the battery to drain down and once those systems don’t see proper voltage they’ll start doing weird things. Especially if the CAN network isn’t getting the proper voltage to send messages from module to module things start to get fucky. Would definitely start with the basics, have the battery tested to see the health of it and then have the alternator tested for proper charging output.
@Vail
No! It was actually the traction control light that came up first then the flashing engine light then came the rest until it stopped accelerating entirely, will definitely be getting battery checked asap and then go from there.
@Hale
Is it a 17-18 elantra? If so the rear wheel speed sensor extension wire has a weird bend from factory and the wire breaks over time.
Vail said:
@Hale
Is it a 17-18 elantra? If so the rear wheel speed sensor extension wire has a weird bend from factory and the wire breaks over time.
2018 sonata, not sure if the sonatas have the same defect on them from the factory?
@Hale
No not really.
Got a code scanner? First owner?
Lennon said:
Got a code scanner? First owner?
I’m the second owner of the vehicle, I did check the code when my engine light was on for a bit and it kept pulling a p0456, which was a small EVAC leak but was told it wasn’t a huge deal and it would turn off on its own, which it did for two months until now.
@Hale
Flashing light usually mean knock sensor issue. So go to dealer might be covered.
Do you have the OBDII bluetooth device? Easiest way to know what you’re dealing with.
Justice said:
Do you have the OBDII bluetooth device? Easiest way to know what you’re dealing with.
I do not:/ I’ll definitely look into getting one though before I tow it to the dealership.
How many miles? Was it running normally up until this event? Full of engine oil I hope? Seems electrical to me?? How old is your battery? Original battery?? REPLACE that first, IMHO. $135 at Wally World.
@Blakeley
69720 miles now, just got my oil changed at 68500 miles (I’ve had to do every 3000 miles since I’ve already had oil consumption issues) battery was new when I bought the car in September of 2023. I plan on checking oil when I get back home today! If not I can try replacing the battery and see if that will help too but on my lojack app the voltage on my car battery is normal it says!
@Hale
You might have your battery load tested. Many auto parts stores will do this for free. Also have your alternator checked for proper voltage output… usually 14.0-14.5 ish. It may be something entirely different… hard to say 100% on these short clips. A professional auto shop with an $$$$ OBD tester should be able to give you better direction! Good luck. Let us know what you find???
@Blakeley
Yes I’m going to do my best to keep up on here with results of all this, hopefully, this doesn’t happen to anyone else at this point! And ofc I have a full work load this week it’s gonna be a long one🥵.