Question 1

What does P0401 mean?

Accepted Answer

P0401 - EGR Flow Insufficient. EGR valve isn't flowing enough exhaust gas. Passages may be clogged.

Question 2

What are the symptoms of P0401?

Accepted Answer

Check engine light, May fail emissions test, No drivability issues

Question 3

What causes P0401?

Accepted Answer

Carbon-clogged EGR passages, EGR valve stuck partially closed, Failed EGR vacuum solenoid, Clogged DPFE sensor tubes (Ford), Failed DPFE sensor (Ford)

Question 4

How much does it cost to fix P0401?

Accepted Answer

Typical repair cost: $50-$400. On Ford, the DPFE sensor ($30-60) is the most common cause. On others, clean the EGR valve and passages.

P0401 — EGR Flow Insufficient

Don't guess — diagnose P0401 the right way

Common symptoms of P0401

Common causes of P0401

Repair cost & difficulty

Vehicles commonly affected

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