P0404: Exhaust Gas Recirculation "A" Control Circuit Range/Performance
The EGR valve position reported back to the computer is outside the range it expects for the command it gave.
What P0404 means
P0404 compares what the EGR valve was told to do with what its position sensor says it did. RepairPal explains that it sets when the EGR valve position sensor is reading above or below the specified range. If the computer commands 30 percent open and the sensor reports 5 percent, or reports the valve open at idle, the code sets. Carbon is a big factor, since it can make the valve stick part way or move slowly. A failing position sensor or a bad wire in its circuit can produce false readings even when the valve works fine. On vacuum valves, a weak vacuum supply can keep the valve from moving as far as it should. Because the valve may be stuck open or closed, symptoms range from pinging under load to a rough idle. Shops command the valve through its range with a scan tool, compare commanded and actual position, and test the sensor voltage. Cleaning or replacing the valve fixes most cases.
Common symptoms
- Check engine light on
- Pinging under load
- Rough idle or stalling if the valve sticks open
- Hesitation
- Failed emissions test
Most common causes
- EGR valve sticking from carbon
- Faulty EGR valve position sensor
- Wiring or connector problem in the sensor circuit
- Weak vacuum supply to the valve
- Failed electric EGR valve motor
What to check yourself first
Check the EGR valve connector and the vacuum hose if it has one. A valve that sticks from carbon may set this code intermittently, often after long idles or short trips. Note any rough idle that comes and goes.
Typical fixes and what they cost
| Fix | Typical cost | Note |
|---|---|---|
| Replace EGR valve | $489-$632 | If the valve sticks or does not follow its command. |
| Replace EGR valve position sensor | $107-$133 | When the position sensor reads wrong but the valve moves fine. |
| Electrical diagnosis to find a wiring or connector fault | $122-$179 | For wiring or connector faults in the sensor circuit. |
| Check engine light diagnosis at a shop | $125-$183 | Includes cleaning carbon that can make the valve stick. |
Typical US price ranges for parts and labor, not quotes. Your shop should confirm the cause with a diagnostic before replacing parts.
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