What can be the cause for P1326 code?

 

Hello, I have a 2017 Hyundai Sonata Hybrid that got this same code. After 3 months at the dealer, they discovered that my car engine has an issue with Carbon build-up. The dealer wanted to replace the EGR Valve, EGR Cross-over pipe, and intake manifold. I opted to take it to my mechanic, he performed a Carbon cleanup. I switched to top Tier Premium for the higher octane, which produces less carbon, and does not pre-ignite. Also, this gas supposedly has more cleaner. However, for GDI engines, it won't help much for cleaning your engine valves. Once a month I use a bottle of Techron. I will probably do a engine decarb once every two years now. Since I done this, my car has been running good and thrown no codes. Previously, my car failed like 5 times going into limp mode. The dealer replaced the ECU, Brake Relay computer. The main Fuse and something else I can't remember and none of those fixed my issue. Apparently, Hyundai discovered these engines has a carbon buildup issue.

 

Carbon build up is a common problem with direct fuel injected engines just about everybody's.

 

It sure is, however, carbon buildup in the Intake Manifold appears to be a big issue on the Hybrid 2L engine. The passages in the intake manifold are being blocked with carbon.

 

Do you think there may be a problem with the PCV system pulling in oil and caking it in there?

 

When I pulled the PCV, it was clean. I replaced the PCV anyway. I cleaned my EGR valve and EGR Cross pipe. I pulled the Intake manifold and cleaned it too. It was dirty. So far my car has been running great. I hope it stays that way, going into limp mode is not fun on a freeway going 70 mph. Limp mode happened 4 times. Replaced ECU and brake Relay. Knock sensors and the main battery fuse. Nothing helped, except when I cleaned my EGR, EGR Cross pipe, and Intake Manifold. I am now running Top Tier gas full-time and running a fuel cleaner, even though that won't necessarily clean my valves. I will be cleaning my Intake Manifold, EGR manually once a year. Probably over-kill???