P0404 code meaning
EGR A Control Circuit Range/Performance
Powertrain system Generic code P04xx codes Check engine light
What P0404 means
Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. P0404 is the function check of the valve drive: on valves with a position sensor the module compares commanded and actual position, and a persistent deviation means the valve sticks, is coked or its drive is too weak (GM diesel 2018 above 10 %, GM gasoline 2004 above 15 %, both MIL after two trips). Ford calls it control stuck. Saab's V6 diesel deviates and uses P0404 for a short to positive. EGR control is then switched off and the valve de-energised.
P0404 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor1 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P0404
- Check engine light on
- EGR deactivated
- Rough idle or jerking if the valve hangs open
- Diesel: possibly reduced power
Common causes of P0404
- Most likelyValve coked or stiff
- PossibleValve drive (motor, gear) worn
- PossiblePosition sensor in the valve inaccurate
- Less likelySupply voltage too low or ground fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR valveEGR valve actuatorEGR wiringEngine control module
What each part of P0404 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 04 | The exact fault in that area. |
What to do next
- Note P0404 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0404
What does P0404 mean?
P0404 means "EGR A Control Circuit Range/Performance". Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. It is a generic code, so it means the same on every make.
Is it safe to drive with P0404?
Drive gently and only to a workshop. With P0404 the car can go into limp mode (reduced power) to protect itself.
Will P0404 fail an emissions test?
Yes, it can. P0404 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0404 to fix?
Difficulty: medium. A typical repair takes 1 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0404 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.