P0404
PowertrainEmission Controlsmoderate severityEGR Control Circuit Range/Performance
What P0404 Means
The EGR valve is not responding as commanded by the PCM.
Symptoms
- Check Engine Light
- Rough idle
- Stalling
- Poor performance
Common Causes
- Carbon restricting EGR valve movement
- Faulty position sensor in EGR
- EGR valve mechanically stuck
Diagnostic Steps
- Command EGR open/closed with scan tool and monitor position
- Check for carbon restricting movement
- Test position sensor
Where to start: Clean or replace EGR valve.
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Budget handheld~$40
ANCEL AD410 →
No-phone-needed handheld — reads, clears, live data, freeze frame.
✓ ANCEL official store
Serious DIY~$100
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
SHOP FAVORITEShop-grade tablet~$300
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
✓ Autel official store
Pro diagnostics$1,500+
Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Related Codes
Community Confirmed Fixes
No confirmed fixes yet for this code. Be the first to contribute!
Submit a FixFound a Fix for P0404?
Help other technicians by sharing what worked on your vehicle.
Submit Your Fix