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P0404moderate severityPowertrain

EGR Control Circuit Range/Performance

on 2011 Subaru WRX STI 2.5L H4 Turbo EJ257 Gen2 · AWD

What this code 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

  1. Command EGR open/closed with scan tool and monitor position
  2. Check for carbon restricting movement
  3. Test position sensor

Repair notes

Clean or replace EGR valve.

Other Powertrain codes on this vehicle

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