What are the symptoms of P0404?

Common symptoms include: Reduced power; Rough running; Check-engine light.

What causes a P0404 code?

The most common causes are: Carbon-bound EGR valve; Faulty EGR position sensor; Actuator/wiring fault.

How do you fix P0404?

Command the valve and watch position feedback; Clean or replace the EGR valve; Check the actuator circuit. Worth diagnosing soon — left alone, the underlying issue can grow into a bigger, costlier problem.

OBD-II Code Lookup

P0404Watch

EGR Control Circuit Range/Performance

Emissions system

The EGR valve isn't moving to the position the computer commands — its feedback is out of range, often from carbon binding the valve.

Worth diagnosing soon — left alone, the underlying issue can grow into a bigger, costlier problem.

Common symptoms

Reduced power
Rough running
Check-engine light

Common causes

Carbon-bound EGR valve
Faulty EGR position sensor
Actuator/wiring fault

How it's diagnosed & fixed

Command the valve and watch position feedback
Clean or replace the EGR valve
Check the actuator circuit

Got P0404? Get it diagnosed.

A real technician can interpret P0404 in the context of your truck and symptoms — and tell you what's actually wrong before you buy parts.

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Related Emissions codes

P0401EGR Flow Insufficient Detected P0402EGR Flow Excessive Detected P0420Catalyst System Efficiency Below Threshold (Bank 1)P0470Exhaust Pressure Sensor Fault

Reference only. A trouble code names a symptom, not the failed part — always confirm with a live diagnosis before repairs. See our Knowledge Base for deeper guides.