What P0404 means
Exhaust Gas Recirculation Circuit Range/Performance
How to diagnose
- Read freeze frame data. When P0404 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P0404 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P0404 for slightly different failure modes:
| BMW | Exhaust Gas Recirculation Control Circuit Range/Performance |
| FIAT | EGR engine, Electrical fault |
| FORD | EGR Circuit Range/Performance |
| GM | Exhaust Gas Recirculation (EGR) Control Circuit Low Voltage; Exhaust Gas Recirculation (EGR) Control Circuit High Current; Exhaust Gas Recirculation (EGR) Control Circuit Malfunction; Exhaust Gas Recirculation (EGR) Control Circuit Malfunction; Exhaust Gas Recirculation (EGR) Control Circuit Too Few Transitions; Exhaust Gas Recirculation (EGR) Control Circuit Too Many Transitions; Exhaust Gas Reci... |
| HONDA | Exhaust Gas Recirculation (EGR) Control Circuit Range/Performance Problem |
| MITSUBISHI | Exhaust Gas Recirculation Circuit Range/Performance; EGR control valve stuck |
| NISSAN | Exhaust Gas Recirculation Circuit Range/Performance |
| VOLKSWAGEN | Exhaust Gas Recirculation (EGR) Open Position Performance |
Read P0404 on your own car
DIY Fix My Car reads P0404 plus 25,000+ other DTC codes with manufacturer-specific descriptions. Includes freeze frame data, likely fix parts, and AI mechanic chat. Download free.