Details On DTCs

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC P3400:00 (PCM, SKYACTIV-G) DETECTION CONDITION AND POSSIBLE CAUSE

Description	Cylinder deactivation system malfunction
Detection condition	Determination conditions	A condition continues in which both the intake valve and exhaust valve for No. 1 or No. 4 cylinder open mistakenly during cylinder deactivation control.
	Preconditions	During cylinder deactivation control
	Malfunction determination period	0.5 s period
	Drive cycle	2
	Self test type	CMDTC self test
	Sensor used	A/F sensor
Fail-safe function	Inhibits the cylinder deactivation control.
Vehicle status when DTCs are output	Not applicable
Possible cause	Switchable HLA malfunction OCV for No. 1 cylinder deactivation malfunction OCV for No. 4 cylinder deactivation malfunction Intake valve and exhaust valve for No. 1 cylinder stuck open malfunction Intake valve and exhaust valve for No. 4 cylinder stuck open malfunction Engine oil solenoid valve malfunction Engine oil malfunction Use of unspecified engine oil Engine oil leakage Low engine oil pressure Engine oil runners are clogged or have leakage PCM malfunction