What does code P0401 mean on a Nissan and is it safe to drive?
P0401: Exhaust Gas Recirculation Flow Insufficient. Here's what it means on your Nissan, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
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What this code means
The EGR system is not flowing enough exhaust gas. Usually due to carbon buildup or a stuck valve.
Common causes for your Nissan
- Carbon-clogged EGR valve or passages
- Faulty EGR valve
- Faulty EGR position or differential pressure sensor
Symptoms
- Check Engine Light
- Rough idle, hesitation
- Knock under acceleration
Typical fixes
- Clean or replace EGR valve
- Clean EGR passages in intake
- Replace EGR sensor if applicable
Repair cost range
For a Nissan, repairs for P0401 often fall between $150 and $600, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Nissan
Nissan's VG33E V6 is notorious for severe EGR passage carbon blockage. Complete port cleaning in the intake manifold is almost always required—the EGR valve alone rarely resolves it. Remove the upper intake and manually clean every EGR port to prevent recurrence.
Most commonly affected models
Pathfinder VG33E 2001–2004Frontier VG33E 2001–2004Xterra VG33E 2000–2004