Emission controls · Powertrain · generic (SAE-defined)
P0404: Exhaust Gas Recirculation "A" Control Circuit Range/Performance
P0404 means the exhaust gas recirculation (EGR) valve is not reaching the position the engine computer commands, or its position reading is outside the expected range.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0404 sets
On vehicles with an electronic EGR valve, the powertrain control module (PCM) compares the commanded valve opening with the actual position reported by the EGR position sensor. If the two disagree by more than a calibrated amount for a set time, or the closed-position reading drifts, the PCM sets P0404. The tolerance and timing are manufacturer-specific.
Common causes of P0404
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Carbon buildup causing the EGR valve to stick or move slowly
- Failing EGR valve position sensor
- Worn electronic EGR valve motor
- Poor connection or high resistance in the EGR wiring
- Low vacuum supply on vacuum-operated valves
P0404 symptoms
- Check engine light on
- Rough idle or stalling
- Hesitation on acceleration
- Pinging under load
- Possibly no symptoms
How P0404 is diagnosed
- Read freeze frame data and check for other EGR codes such as P0405 or P0406
- Watch commanded versus actual EGR position in live data while commanding the valve with a scan tool
- Check the closed-position reading at key on, engine off, against specification
- Inspect the connector and harness for corrosion or loose terminals
- Remove and inspect the valve for carbon that binds the pintle
- Verify vacuum supply on vacuum-type valves
Typical fixes for P0404
- Clean carbon from the EGR valve and passages
- Replace the EGR valve assembly (often includes the position sensor)
- Repair wiring or connector faults
- Restore proper vacuum supply
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Manufacturer notes
Commonly reported on GM engines from the late 1990s and 2000s with electronic linear EGR valves. Definitions can vary by manufacturer; check factory service information.
Related codes & warning lights
P0404 FAQ
What does code P0404 mean?
P0404 means the exhaust gas recirculation (EGR) valve is not reaching the position the engine computer commands, or its position reading is outside the expected range. The standard definition is "Exhaust Gas Recirculation "A" Control Circuit Range/Performance."
Can I drive with a P0404 code?
In most cases yes for short distances. If the valve sticks open you may get rough idle or stalling, so avoid long trips and get it checked within a few days.
Will cleaning the EGR valve fix P0404?
It can if carbon is making the valve stick. If the position sensor or motor inside the valve has failed, the valve assembly usually needs replacement.
Why does P0404 show up more in cold weather?
Moisture and carbon deposits can make a marginal valve stick more when cold, causing a delay between command and response that triggers the code.
Keep researching
More emission controls codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
- California Air Resources Board — On-Board Diagnostic (OBD) Program
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.