Code result
P3400
Cylinder Deactivation System Bank 1
Moderate severity
What it means
The engine control module has detected a fault in the cylinder deactivation system on bank 1. Variable displacement engines shut off cylinders under low load to save fuel — a fault here disables the function.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Deactivation solenoid or oil control valve failed
highOne of the most commonly reported causes for this code — check this first.
Collapsing lifter stuck
mediumA plausible cause — test and verify before replacing parts.
Low oil pressure prevents activation
mediumA plausible cause — test and verify before replacing parts.
Related help
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