Generic OBD DTC

Ford P0401: EGR Insufficient Flow

Detected EGR flow is below the expected threshold — an EGR diagnosis, not a readiness-status code.

Handheld scan tool on a car seat connected for an OBD readiness check

Moderate — diagnose the related faultEGR

What the code tells you

EGR monitoring detected insufficient flow under that test’s conditions.

What it does not tell you

That every Ford with P1000 has a clogged EGR valve.

Diagnostic direction

1
If the EGR/VVT monitor is the incomplete item and P0401 is stored, follow EGR diagnosis.
2
Many late-model Fords use VVT rather than a classic EGR valve; confirm the actual hardware.

Related codes

P1000

Possible causes are listed only when they are this code’s actual meaning — not a generic template pasted onto every DTC.

This site provides general diagnostic information. Vehicle procedures vary by model, year, engine, and calibration. Follow Ford service information and local regulations, and use a qualified technician when diagnosis or repair exceeds your experience.