2013 Kia Rio P0326

[u/Shantstaaah]

My girlfriend bought a used 2013 Kia Rio from a dealership about 2 and a half years ago with about 67,000 miles on it. Fast forward to right now and it has about 94,000 miles on it.

The other day the engine light came on and I scanned it with my OBD scanner tool, the code came out to be P0326, no other codes showed up except this one. We took it to a local mechanic and asked to replace the knock sensor on the vehicle, once the sensor got replaced about a day later the same code appeared with a check engine light.

I’d like to add that even with the engine light on this car it drives perfectly fine, it accelerates fine and goes up to freeway speeds without any hesitation, jolting, or engine knock noises. I’ve had my girlfriend rev the car in park at 2-3k RPM as I listened for any abnormal sounds, couldn’t hear anything that sounded like engine knock.

Called Kia and asked them to check if there is any software update on the ECM that is needed because I’ve heard stories that the ECM can throw out faulty codes and needs an update, was told that there is nothing for our Kia based off of the VIN we gave them.

We took it to another mechanic today to try and have them diagnose the new sensor, wiring harness, and to hear if there is an engine knock happening. A couple hours later we got a call from the mechanic stating that the new sensor is good, the wiring harness is good, and that the engine itself is healthy but there MIGHT be carbon buildup since this is a GDI engine and that they’re prone to having carbon buildup. Ive seen past videos and experiences where people have fixed engine knocking and such by walnut blasting the carbon off and restoring the intake valves and pistons.

I wanted to ask if there are any other things that I should do before going along with walnut blasting. This car has been well maintained over the years we have had it, we always made sure to get an oil change before it hit 5,000 miles and we have added fuel additives over time to clean the engine even though it’s a GDI engine and it basically skips the part where gasoline sprays onto intake valve.

I hope some of you are able to point me in the right direction with what to do next. Thank you.