DTC P0401:00 [MZR 1.3, MZR 1.5]

id0102f8704200

DTC P0401:00

EGR flow insufficient detected

DETECTION CONDITION

•  The PCM monitors the difference in the intake manifold pressures when the EGR is operated and when it is stopped. If the difference is too small, the PCM determines that the EGR flow insufficient.

Diagnostic support note

•  This is an intermittent monitor (EGR system).

•  The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.

•  PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle.

•  FREEZE FRAME DATA (Mode 2)/Snapshot data is available.

•  The DTC is stored in the PCM memory.

POSSIBLE CAUSE

•  MAP sensor malfunction

•  EGR valve malfunction

•  EGR valve passage malfunction

―  Gasket of EGR valve malfunction

―  EGR valve passage blockage

•  PCM malfunction

DTC P0401:00	EGR flow insufficient detected
DETECTION CONDITION	• The PCM monitors the difference in the intake manifold pressures when the EGR is operated and when it is stopped. If the difference is too small, the PCM determines that the EGR flow insufficient. Diagnostic support note • This is an intermittent monitor (EGR system). • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. • PENDING CODE is available if the PCM detects the above malfunction condition during first drive cycle. • FREEZE FRAME DATA (Mode 2)/Snapshot data is available. • The DTC is stored in the PCM memory.
POSSIBLE CAUSE	• MAP sensor malfunction • EGR valve malfunction • EGR valve passage malfunction ― Gasket of EGR valve malfunction ― EGR valve passage blockage • PCM malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED • Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (EGR system related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED SERVICE INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service Information. • If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE AND/OR DTC • Switch the ignition to off, then to ON (engine off). • Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.3, MZR 1.5].) • Are any other PENDING CODEs and/or DTCs present?	Yes	Go to the applicable PENDING CODE or DTC inspection. (See DTC TABLE [MZR 1.3, MZR 1.5].)
3		No	Go to the next step.
4	INSPECT MAP SENSOR • Switch the ignition to off. • Inspect the MAP sensor. (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION [MZR 1.3, MZR 1.5].) • Is there any malfunction?	Yes	Replace the MAP sensor, then go to Step 7. (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)
4		No	Go to the next step.
5	INSPECT EGR VALVE OPERATION • Perform the EGR Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 1.3, MZR 1.5].) • Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 7.
5		No	Go to the next step.
6	INSPECT EGR VALVE PASSAGE • Switch the ignition to off. • Remove the EGR valve. (See EGR VALVE REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].) • Visually inspect the gasket installation of EGR valve and EGR valve passage for blockage. • Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
6		No	Go to the next step.
7	VERIFY DTC TROUBLESHOOTING COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [MZR 1.3, MZR 1.5].) • Perform the Drive Mode 03 (EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S and TWC Repair Verification Drive Mode). (See OBD DRIVE MODE [MZR 1.3, MZR 1.5].) • Stop the vehicle and access the ON BOARD READINESS TEST to inspect the Drive Mode completion status. • Verify that the ON BOARD READINESS TEST status changing to YES. • Perform the KOER self test. (See KOEO/KOER SELF TEST [MZR 1.3, MZR 1.5].) • Is the PENDING CODE for this DTC present?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].) Go to the next step.
7		No	Go to the next step.
8	VERIFY AFTER REPAIR PROCEDURE • Perform the “AFTER REPAIR PROCEDURE”. (See AFTER REPAIR PROCEDURE [MZR 1.3, MZR 1.5].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZR 1.3, MZR 1.5].)
8		No	DTC troubleshooting completed.