OBD-II Code · Emissions
P0404
EGR Control Circuit Range/Performance
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$150–$500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
EGR actuator not tracking commanded position.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
- Rough idle
Likely causes
- Failed EGR actuatorMost common
- Carbon buildup
- Wiring
Read the full diagnostic procedureP0404 is an EGR control circuit range/performance fault — distinct from P0403 in that the circuit isn't open or shorted, but the feedback the ECM see…
P0404 is an EGR control circuit range/performance fault — distinct from P0403 in that the circuit isn't open or shorted, but the feedback the ECM sees during commanded actuation doesn't match the expected range. The valve might move, but not as far or as fast as the ECM expects; or the position sensor reports a value that's electrically valid but mechanically implausible given the command.
Diagnostic ladder
- scan-tool the EGR position-sensor live data and command the valve through its full sweep with bidirectional control — a healthy linear or stepper EGR should hit every commanded step within ~100ms with position feedback tracking command to within 5%. If commanded position is 50% and feedback reads 20%, the valve is either binding from carbon (mechanical) or the position sensor itself is drifting (electrical).
- On stepper-motor EGRs (GM linear, Toyota/Honda stepper), one of the three coils failing causes commanded-vs-actual mismatch without throwing an open/short code — measure all three coil resistances and compare.
- Carbon binding is again the dominant root cause past 80,000 miles: the pintle moves freely for the first 30% of travel and then stalls against a carbon ridge, the ECM sees commanded-vs-actual divergence, and P0404 sets.
Vehicle-specific patterns2003-2010 GM 3.5/3.9L V6 (Impala, Malibu, Uplander) and 4.8/5.3L truck V8s throw P0404 from a binding linear EGR valve — clean the seat and pintle wi…
- 2003-2010GM 3.5/3.9L V6 (Impala, Malibu, Uplander) and 4.8/5.3L truck V8s throw P0404 from a binding linear EGR valve — clean the seat and pintle with carb cleaner; if it doesn't restore smooth sweep on the scan tool, replace.
- 2002-2008Honda Accord/Odyssey V6 throws P0404 from coked-up valve and clogged downstream ports together — cleaning the valve alone won't clear it on this platform; the intake manifold has to come off.
- 2001-2007Toyota Camry/Avalon 1MZ-FE 3.0L V6 throws P0404 from a sticking EGR vacuum modulator combined with a failing EGR temp sensor — both are cheap parts, replace the pair.
- 2005-2012Ford F-150 5.4L 3V throws P0404 from a carbon-restricted EGR tube where it connects to the exhaust crossover — the tube has to be pulled and cleaned or replaced.
Estimated repair$30 (clean and reset) to $400+ (valve + tube + intake gaskets).
Look up another code
P0404 — frequently asked
What does a P0404 code mean?
EGR actuator not tracking commanded position.
What causes a P0404 code?
Common causes: Failed EGR actuator; Carbon buildup; Wiring.
What are the symptoms of a P0404 code?
Typical symptoms: Check engine light; Rough idle.
Is it safe to drive with a P0404 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $150-$500.
How do I diagnose a P0404 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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