Cylinder Deactivation Solenoid Issues

[Marebito]

Hey everyone,

I’ve got a 2018 Mazda CX-5 2.5L with about 190,000 miles, and I’m dealing with a P3400 code related to the cylinder deactivation system. The car’s showing symptoms like misfires, which is on cylinder one and I plan to do spark plug change soon.

I’ve already:

• Checked oil level and condition (looks okay)
• Verified spark plugs and coils
• Located the cylinder deactivation solenoid(s) (I believe there one, but could be wrong)

Any advice, diagrams, or part recommendations would be hugely appreciated.

Thanks in advance,
Jacob