Last reported case: 2 months ago
Based on 6 owner reports (1 from Reddit, 5 from forums)
What is P0401?
P0401 indicates your vehicle's computer has detected insufficient exhaust gas recirculation (EGR) flow, which is part of the emissions control system. This is a medium-severity issue that can cause failed emissions tests and reduced fuel efficiency. Based on real owner data, this code appears most frequently in Honda Accord and Ford Mustang models.
Common Causes:
- Clogged or stuck EGR valve passages (most common issue reported)
- Faulty EGR valve itself
- Blocked EGR cooler or lines
- Malfunctioning EGR position sensor or DPFE sensor
Symptoms:
- Check Engine Light illuminated (universal symptom)
- Reduced engine performance or hesitation during acceleration
- Increased fuel consumption
- Rough idle or engine stalling
- Failed emissions inspection
🚗P0401 on 2010 HONDA Accord
This page focuses specifically on P0401 issues reported by 2010 HONDA Accord owners. The experiences and fixes below are from real owners of this exact vehicle.
Symptoms Reported by 2010 HONDA Accord Owners:
Parts Often Involved:
What Owners Say
Real experiences from 2010 HONDA Accord owners
“(I think something like (“ACS”?) was already on.) brought to mechanic - not avail - he tried to get codes etc. -nothing much (I know nothing about cars).”View original
“brought to mechanic - not avail - he tried to get codes etc. -nothing much (I know nothing about cars). No info from scanner, would need to check it all out to diagnose.”View original
“Also, I got a P0171 (lean) and P0170 (fuel trim malfunction) when this issue popped up. The P0170 cleared after the fuel filter replacement, but I still have P0171 P (pending).”View original
“The P0170 cleared after the fuel filter replacement, but I still have P0171 P (pending). Haven't checked in a little while though, will probably do so tomorrow morning.”View original
“I GOT RID OF THE CHECK ENGINE LIGHT FOR 4 BUCKS! all you need is a bottle of carb cleaner and some basic car tools and an hour or 2 of your time. Go on youtube and watch video on this and I suggest this is the first thing you try before going out and buying an egr valve that you do not need.”View original
“I've performed the EGR port cleaning throughout the car's life a few times even TSB 99-085 where the pipe kit is used in the manifold. EGR valve was replaced with Honda OEM ~ 35k miles ago when I also cleaned the intake manifold last.”View original
“I drove (very low power, missing badly, stalled once at a red light) a few miles to the shop & read the codes (Blue Driver). P0401 (EGR System leak detected) P2646 (A Rocker Arm Actuator System performance/Stuck off bank 1) P0301, P0302, P0300, P0304 Cylinders misfiring (no P0303).”View original
“I arrived & started the engine to see if it could be moved in what I assumed to be limp mode. I drove (very low power, missing badly, stalled once at a red light) a few miles to the shop & read the codes (Blue Driver).”View original
“'02 Accord V6 P0401/P1399 Driveability Issues I have a 2002 Honda Accord EX V6 auto sedan with ~267k miles giving codes P0401 (EGR Insufficient Flow) and P1399 (multiple random misfire) with driveability issues.”View original
“Go on youtube and watch video on this and I suggest this is the first thing you try before going out and buying an egr valve that you do not need. Chances are this will prob be your problem as well.”View original
These are real experiences shared by 2010 HONDA Accord owners on automotive forums and communities. Results may vary based on vehicle condition and repair quality.
About This Data
This page aggregates 6 discussions about P0401 from 2010 HONDA Accord owners across automotive communities.
Success rate (50%) is calculated from posts where owners confirmed whether their fix resolved the issue.
Last updated: 12/30/2025