P0404

EGR A Control Circuit Range/Performance

Emissions / EGR Generic OBD-II Medium

What it means

P0404 means the exhaust gas recirculation (EGR) valve isn't performing within the expected range — the ECM commands a position but the valve's actual position or feedback doesn't match. The usual culprit is carbon buildup gumming up the valve so it sticks or responds sluggishly. The engine keeps running, but you may notice a rough idle or hesitation, and it will fail an emissions test until the EGR system works properly.

Medium

Can I keep driving? Usually safe to drive — the engine runs, though a stuck EGR valve can cause rough idle or hesitation; get it cleaned or checked before an emissions test.

Real-world scan data

Seen in

1,290

scans in the past year

Found in

0.2%

of scans

0.4%

of scans that found faults

Appears alongside · share of P0404 scans

P0113in 16.8% of scans

P0101in 14.4% of scans

P0183in 11.5% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Rough idle or occasional stalling (valve stuck open)
Hesitation, pinging, or reduced performance under load
Failed emissions test

Common causes

Most likely first

Carbon-clogged EGR valve sticking or not tracking commands — most commonLikely
Faulty EGR valve or its position sensorCommon
Wiring or connector fault in the EGR control circuitCommon
Vacuum/electrical control problem, or rarely the ECMLess often

How to diagnose & fix

Work through it in order

Scan the live EGR position/feedback data and command the valve to see if actual position matches.
Remove and inspect the EGR valve for carbon buildup; clean the valve and passages — a very common fix.
Check the EGR control wiring and connector for damage or corrosion.
Replace the EGR valve or position sensor if it won't track commands, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0404?+

Generally yes. It's an emissions/EGR performance fault, so the engine still runs, but if the valve is stuck open you may get a rough idle or stall. Have it cleaned or checked soon, and note you'll fail an emissions test until it's fixed.

Can I just clear P0404?+

It will return once the ECM re-tests EGR operation if the valve still isn't tracking correctly. Cleaning or replacing the valve is what makes it stay off.

Read & clear P0404 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX