Nissan Sentra B18 (2020-2025) Service Manual / Engine / Work Procedure (After Replacing Electric Throttle Control Actuator) / Dtc/circuit Diagnosis / P0401 Egr Function

Nissan Sentra B18 (2020-2025) Service Manual: P0401 Egr Function

Dtc Description

DTC Description

DTC DETECTION LOGIC

DTC	CONSULT screen terms (Trouble diagnosis content)	DTC detection condition
P0401	EGR A FLOW INSUFFICIENT (EGR "A" flow insufficient detected)	Diagnosis condition	—
		Signal (terminal)	EGR volume control valve
		Threshold	When ECM detects that negative pressure variation in intake manifold is smaller than the variation corresponding to EGR valve opening in case of opening/closing EGR control valve in a condition fuel supply is cut.
		Diagnosis delay time	—

POSSIBLE CAUSE

EGR cooler clogged
EGR pipe clogged
Incorrect EGR pipe connection

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).

Idle Start/Stop System

Not applicable

Confirmation Procedure

Confirmation Procedure

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

>>
GO TO 2.
PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and warm it up to normal operating temperature.
2. Drive the Nissan Sentra vehicle at 80 km/h (50 MPH).
  
  CAUTION:
  
  Always drive vehicle at a safe speed.
3. Release the accelerator pedal fully until the Nissan Sentra vehicle speed decreases to 40 km/h (25 MPH).
4. 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

CHECK EGR PASSAGE

Check the following parts for clogging and damage.
- EGR tube
- EGR hose
- EGR cooler
Is the inspection result normal?
YES >>
GO TO 2.
NO >>
Repair or replace malfunctioning part
CHECK EGR VOLUME CONTROL VALVE VISUALLY
1. Remove EGR volume control. Refer to Removal and Installation.
2. Check if foreign matter is caught between the EGR volume control valve and the housing.
Is the inspection result normal?
YES >>
GO TO 3.
NO >>
Repair or replace malfunctioning part.
CHECK EGR COOLER VISUALLY
1. Remove EGR cooler. Refer to Removal and Installation.
2. Check if foreign matter is caught between the EGR cooler and the housing.
Is the inspection result normal?
YES >>
INSPECTION END
NO >>
Repair or replace malfunctioning part.

P0365 Exhaust Valve Timing Control Position Sensor

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P0402 Egr System

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