The knock sensor (code 34) code is 90% of the time because of a short in your wiring to the knock sensor. Other times, the sensor itself has melted or been destroyed. It will not harm your engine driving like that. However, because that code 34 is stored on your ECU, you will notice your engine produces a lot less power than normal (timing is retarded to prevent knock). To fix the issue you need to find the short in the wiring and splice/solder to repair it (or replace the sensor itself if it's bad). If you search around for "code 34" you will find many posts on the topic, where to look for the short, how to replace the knock sensor, etc. It's a common issue on the KA24DE.
IACV I don't know the solution, you may have a short or the unit itself might be bad/gummed up/etc.