P3400 error code; already replaced oil pressure switch

2handband

The check engine light is on, and it returned a P3400 error code. I replaced the oil pressure switch on the appropriate cylinder bank... same problem. Does anyone know what the next step is, and if it's something I can reasonably do by myself?

thecardoc3

There are some essential tools that help make proving what is wrong a lot easier. The switch only reports that a minimal value of oil pressure has been sent to the valve pause rockers. As far as possible causes it "could be" that the oil is low, or an oil and filter service might be required. A common cause is historical service frequency and product choices may have allowed deposits to occur inside the engine passages. If you remove the solenoid assembly for the valve pause system, you will see a screen in the gasket assembly. If there are oil deposits restricting the screen then you are on the right path. Replacing the solenoid assembly and gasket plus changing the oil and filter may restore operation of the system. If there are deposits observed this is very likely to keep reoccurring.