DTC Detection Logic

WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.

The after treatment diesel exhaust fluid controller (DCU) did not receive specific dosing request messages from the Engine Control Module (ECM).

DTC	CONSULT screen terms (Trouble diagnosis content)	DTC detection condition
U040F-00	(Invalid Data Received From Reductant Control Module)	1	Diagnosis condition	Ignition switch is ON or engine running.
			Signal (terminal)	(-)
			Threshold	The flange controller unit (FCU) has detected an engine control module (ECM) SAE after treatment 1 SCR dosing system requests 1 message that is out of sequence.
			Diagnosis delay time	Diagnostic runs continuously when the engine is running.
		2	Diagnosis condition	Ignition switch is ON or engine running.
			Signal (terminal)	(-)
			Threshold	The flange controller unit (FCU) has not received the SAE after treatment 1 SCR dosing system requests 1 message from the ECM. or The FCU has not received the SAE after treatment 1 SCR dosing system requests 2 message from the ECM. or The FCU has not received the SAE ambient conditions message from the ECM. or The FCU has not received the diagnostic override message from the ECM.
			Diagnosis delay time	Diagnostic runs continuously when the engine is running.