EGR Flow Insufficient Detected
2007-2012 Nissan Altima 2.5L I4
Description
The EGR system is not flowing enough exhaust gas. This is one of the most common EGR codes.
Symptoms
- Check Engine Light
- Pinging under load
- Failed emissions (high NOx)
- Slight rough idle
Common Causes
- Clogged EGR passages (most common)
- EGR valve stuck closed
- Clogged EGR tube
- Faulty DPFE/MAP sensor
- Carbon buildup in intake manifold
Diagnostic Steps
- Check EGR passages for carbon restriction
- Test EGR valve by applying vacuum (should open and idle should change)
- Inspect EGR tube between exhaust and valve
- Test DPFE sensor (Ford) or EGR position sensor
- Clean carbon from intake ports
Repair Notes
Clean EGR passages and valve. This is maintenance, not just a repair. Replace EGR valve if cleaning fails.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P0401 on Other Vehicles
Nissan 200SX
1995-1998 1.6L I4 GA16DE
Nissan 200SX SE-R
1995-1998 2.0L I4 SR20DE
Nissan 240SX
1995-1998 2.4L I4 KA24DE
Nissan 300ZX
1990-1996 3.0L V6 VG30DE
Nissan 300ZX Twin Turbo
1990-1996 3.0L Twin-Turbo V6 VG30DETT
Nissan 350Z
2003-2006 3.5L V6 VQ35DE
Nissan 350Z
2007-2009 3.5L V6 VQ35HR
Nissan 370Z
2009-2020 3.7L V6 VQ37VHR
Common Questions
What does code P0401 mean on a 2007-2012 Nissan Altima?
P0401 stands for "EGR Flow Insufficient Detected". The EGR system is not flowing enough exhaust gas. This is one of the most common EGR codes.
What are the symptoms of P0401 on a Nissan Altima?
Common symptoms of P0401 include: Check Engine Light, Pinging under load, Failed emissions (high NOx), Slight rough idle.
What causes P0401 on a 2007-2012 Nissan Altima?
Common causes of P0401 include: Clogged EGR passages (most common), EGR valve stuck closed, Clogged EGR tube, Faulty DPFE/MAP sensor, Carbon buildup in intake manifold.