P0401 on Peugeot: How to Diagnose & Fix
Exhaust Gas Recirculation Flow Insufficient
1 Peugeot model · 1 documented issue · $200-$600 repair
P0401 on Peugeot by model: symptoms, diagnosis and fix
The exhaust gas recirculation valve on diesel 308 models becomes clogged with carbon deposits, causing rough idle and poor performance. The electrically actuated valve sticks in the open or closed position.
Common Symptoms
- Rough idle
- Black exhaust smoke
- Loss of power
- Check engine light
How to Fix
Clean or replace the EGR valve. Install an EGR cooler bypass blanking kit if permitted in your region. Update the ECU software to revised EGR control maps.
Sources for this issue (1)
P0401 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0401 mean on a Peugeot?
P0401 stands for "Exhaust Gas Recirculation Flow Insufficient." This code means the Exhaust Gas Recirculation (EGR) system is not flowing enough exhaust back into the engine. The EGR system recirculates a small amount of exhaust into the intake to lower combustion temperatures and reduce nitrogen oxide (NOx) emissions; the computer has determined the actual flow is below what it commanded. The most common reason is carbon buildup clogging the EGR valve or its passages. You may notice pinging/knocking, rough idle, or a check engine light, and the car will fail emissions testing. On Peugeot it is documented across 1 model: 308.
What are the most common causes of P0401?
The most common causes of P0401 are: Carbon buildup clogging the EGR valve or passages, Stuck or faulty EGR valve, Blocked or restricted EGR ports/tubes, Faulty EGR temperature or position sensor, Faulty DPFE/EGR pressure sensor (on applicable systems), Vacuum leak or failed vacuum control (vacuum-operated EGR), Wiring or connector problems at the EGR valve. The specific cause varies by vehicle.
How much does it cost to fix P0401 on a Peugeot?
Published repair estimates on Peugeot range from $200 to $600 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0401 on a different make?
View P0401 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.