What does code P0401 mean on a Lexus and is it safe to drive?
P0401: Exhaust Gas Recirculation Flow Insufficient. Here's what it means on your Lexus, 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 Lexus
- 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 Lexus, 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 Lexus
Lexus 1MZ-FE V6 P0401 mirrors Toyota Camry V6 diagnosis—carbon buildup in EGR passages and intake runners is the primary cause. Cleaning the EGR valve and intake runner control valve typically resolves it permanently. Newer Lexus engines (post-2006) do not use EGR.
Most commonly affected models
RX300 1MZ-FE 1999–2003ES300 1MZ-FE 2000–2003GS300 2JZ-GE 1998–2005