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Fault code P0404 means EGR circuit operation out of specification. The valve responds to commands but the position reached does not match the one requested.

Typical symptoms

• Reduced performance
• Rough idle
• Engine light on
• More frequent DPF regenerations

Most common causes

• Carbon deposits slowing the valve travel
• Worn position sensor
• Slow or jammed actuator
• Adaptations not performed after replacement

How it is checked in diagnosis

• Comparing requested and actual position during the actuator test
• Cleaning and new test
• Performing the adaptations in diagnosis

Can you drive with code P0404?

Yes, but with a loss of liveliness: soot tends to build up quickly.

How MasterTuning helps

We read the real values from the ECU, not just the code: that is the difference between identifying the component responsible and replacing parts by trial and error. After the repair we clear the fault and check that it does not come back. Centres throughout Italy.

Read more: vehicle database · find an installer · what is ECU remapping

Do you have code P0404 on your car? Book a diagnosis at your nearest MasterTuning centre.

Frequently asked questions

What does fault code P0404 mean?

Code P0404 means EGR circuit operation out of specification. The valve responds to commands but the position reached does not match the one requested.

Can you drive with fault P0404?

Yes, but with a loss of liveliness: soot tends to build up quickly.

Is clearing code P0404 enough to fix it?

No: if the cause is still present the code comes back after a few kilometres. Clearing should only be done after the repair, with the diagnostic tool.

How much does it cost to fix code P0404?

It depends on the component responsible: the diagnosis is precisely what identifies it with real measurements, avoiding unnecessary replacements that cost far more than the correct repair.