What does code P0401 mean on a Honda and is it safe to drive?
P0401: Exhaust Gas Recirculation Flow Insufficient. Here's what it means on your Honda, 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 Honda
- 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 Honda, 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 Honda
P0401 on older Honda EGR-equipped engines is almost always a stuck EGR valve or clogged port. Clean the valve with carbon solvent and verify the vacuum actuator functions. Honda phased out EGR on most models post-2002—confirm your model year has EGR before diagnosing.
Most commonly affected models
Accord 2.3L F23 2000–2002CR-V 2.0L B20 1997–2001Odyssey J35 2001–2004