Nissan Sentra B18 (2020-2025) Service Manual: U042f Can Communication

Dtc Description

DTC Description

DTC DETECTION LOGIC

DTC	CONSULT screen terms (Trouble diagnosis content)	DTC detection condition
U042F	Communication error (invalid) (Invalid data received from camshaft position control module)	Diagnosis condition	Engine running at idle
		Signal (terminal)	CAN communication signal
		Threshold	ECM cannot receive a communication signal sent from the electric intake valve timing control module.
		Diagnosis delay time	10 ms or more

POSSIBLE CAUSE

• Harness or connectors (CAN communication line is open or shorted)

• Electric intake valve timing control module

FAIL-SAFE

Engine Control System

Engine operating condition in fail-safe mode
Fail safe mode		Nissan Sentra Vehicle behavior
Device fix mode		This mode fixes the electric IVT motor and the EVT control solenoid valve in the reference position. The intake manifold runner control valve motor is turned OFF (intake manifold runner control valve opens).
Combustion control mode	Stratified charge combustion control at starting	No stratified charge combustion at starting (cold start).
	Idle speed control	Stops feedback control of idle speed and controls with specified speed.
	Recovery speed control at decelerating	Stops recovery speed control by the fuel cut at decelerating and controls with specified speed.
	Idle neutral control	Stops idle neutral control.
Others		ECM stops the electric valve timing control. (The camshaft returns to the position of most retard angle.)

Idle Start/Stop System

When a DTC is detected, the start/stop indicator lamp blinks slowly and the idle start/stop system operation is prohibited.

When ECM detects error while operating the idle start/stop system, ECM restarts the engine.

Confirmation Procedure

Confirmation Procedure

1. CHECK DTC PRIORITY

   If DTC U042F is displayed with DTC U1000, first perform the trouble diagnosis for DTC U1000.

   Is applicable DTC detected?

   YES >>

   Perform diagnosis of applicable. Refer to DTC Description.

   NO >>

   GO TO 2.

2. PRECONDITIONING

   If DTC Confirmation Procedure has been previously conducted. always perform the following procedure before conducting the next test.

   1. Turn ignition switch OFF and wait at least 10 seconds.

   2. Turn ignition switch ON.

   3. Turn ignition switch OFF and wait at least 10 seconds.

   >>

   GO TO 3.

3. PERFORM DTC CONFIRMATION PROCEDURE

   1. Start the engine and let it idle for at least 1 second.

   2. Check 1st trip DTC.

   Is 1st trip DTC detected?

   YES >>

   Refer to DTC Diagnosis Procedure.

   NO-1 >>

   To check malfunction symptom before repair: Refer to Intermittent Incident.

   NO-2 >>

   Confirmation after repair: INSPECTION END

Dtc Diagnosis Procedure

DTC Diagnosis Procedure

1. CHECK DTC PRIORITY

   If DTC U042F is displayed with DTC U1000, first perform the trouble diagnosis for DTC U1000.

   Is applicable DTC detected?

   YES >>

   Perform diagnosis of applicable. Refer to DTC Description.

   NO >>

   GO TO 2.

2. CHECK CAN COMMUNICATION LINE

   Perform trouble diagnosis of CAN communication system. Refer to Trouble Diagnosis Flow Chart.

   Is the inspection result normal?

   YES >>

   GO TO 3.

   NO >>

   Repair or replace error-detected parts.

3. CHECK INTERMITTENT INCIDENT

   Check intermittent incident. Refer to Intermittent Incident.

   Is the inspection result normal?

   YES >>

   Replace electric intake valve timing control module. Refer to Removal & Installation.

   NO >>

   Repair or replace error-detected parts.