Limp mode

I had the software update done to my 2018 Sonata 2.4 l a month ago. While on vacation my Sonata decided to go into limp mode. It was the knocksenor wiring harness that was the culprit. The factory harness is too taunt and routed too close to body,frame causing a odd frequency to snap the ECM into safe ( limp ) mode. I had it flatdecked to a Hyundai dealership , who had a harness in stock, cut to the chase it's in works great. All under warranty!!

 

Thanks for the information.
It might help someone

 

My 2016 did that. I have 62,000 mile's on my Sonata. Flashing engine light, new wiring harness. Took 3 weeks, but they always gave me a free rental. Drove it 1 weeks engine light flashed again, they tightened down the knock sensor. Two days later, the engine light flashed again, they replaced the knock sensor. Two days later, the engine light flashed again. Now they are installing a new motor. It's all covered under warranty. None of it cost me a penny. I'm getting a new $9000 motor, and I only paid $10,500 for the car.

 

Same thing for me guys. Just different order. Was driving down the freeway and had to come to a quick stop and when I when traffic started moving again and i pushed the gas every light on the dash came on and long story short the engine had seized. Amazingly enough one of the local dealerhips employees turned around in rush hour traffic to let me know about the recall. Hyundai took good care of me and got me a rental and replaced my engine all at no cost to me. I bought this car from a stranger on facebook and it had 150000 miles, so I was shocked that Hyundai really stood by their cars and treated me so well. Anyways, 9 weeks later I got my car back and not even 2 hours later it went into limp mode. It went back to the dealer and they didnt have the harness in stock so they let me drive a brand new 2019 elantra for 3 more weeks.that was fun. Needless to say even though Im now experiencing a couple other problems Hyundai isnt going to take care of for free I still love my car!

 

My experience has been very different. My 2016 Sonata has gone into limp mode but the service department at Hyundai Escondido has no idea what the real problem is. First they said it was the catalytic converter ($3400) and they want $2400 to replace the engine head gasket and carbon build-up cleaning. From what I've read, that does not seem connected to what is happening. I think they do not want to expend the time and resources to find the real issue.

 

Try a different dealer, find out the trouble code, if it's the engine knock code. if they don't want to repair it, unbolt the knock sensor from the engine and isolate from the engine, and run it unlill it siezes, then Hyundai will replace the engine (reinstall the sensor before bringing it in)