2005 Acura P0401: What It Means & Is It Safe to Drive?
P0401 on the 2005 Acura: Exhaust Gas Recirculation Flow Insufficient. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe 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 on the 2005 Acura
- 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 2005 Acura, repairs for P0401 typically fall between $150 and $600, depending on the root cause and labor rates in your area.
Known issues on Acura
Acura P0401 applies to early EGR-equipped models. Post-1998 Acura V6 engines phased out EGR. On early TL and CL with the G25A4 engine, a stuck EGR valve is the typical cause. Verify your model year has EGR before diagnosing.
Most commonly affected models
TL 2.5L G25A4 1995–1998