P0404: Exhaust Gas Recirculation A Control Circuit Range/Performance
What to do
Usually driveable. Expect an emissions failure and possibly a rough idle. Ask for commanded and actual valve position to be compared rather than the valve simply being replaced.
What this code means
The EGR valve is responding, but not in the way the module expects. On an electrically actuated valve with position feedback, this is the code raised when the commanded position and the reported position disagree — the valve is told to move to forty percent and reports twenty, or fails to return fully closed.
Carbon is again the usual mechanism, but here it binds the pintle rather than blocking the passage: the valve moves, slowly and incompletely, instead of not moving at all. Watching commanded against actual position while sweeping the valve through its range is the single most useful test, and it distinguishes a sticking valve from a failed position sensor in one reading.
Likely causes
Start here
- Carbon binding the EGR valve pintle · moderate
- Faulty EGR position sensor · easy
- Stuck or seized EGR valve · moderate
Less common
- Corroded or loose connector · easy
- Insufficient vacuum supply · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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