OBD-II code · Powertrain (generic)

P0404 EGR Range/Performance

The EGR valve does not move through its expected range or its position feedback does not track command. The valve may be sticking, the position sensor may be drifting or carbon buildup is preventing full travel.

Is it safe to drive with P0404?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyCarbon buildup on EGR valve
  • PossiblePosition sensor drift
  • Less likelyMechanical valve damage

Symptoms

  • Check engine light on
  • Pinging or knocking under load
  • Power loss and hesitation
  • Possible rough idle
  • Failed emissions inspection (NOx)

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
0.5–3 h
Emissions test
Likely to fail
Parts involved
Egr Valve, Egr Position Sensor

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.