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2017 CHEVROLET IMPALA

3.6L V6 LFXAWDAUTOMATICgas
Repairs0Labor990Torque9854Fluid15DTC1938Battery2Maintenance0Recalls0
P0400moderate severityPowertrain

Exhaust Gas Recirculation (EGR) Flow

on 2017 Chevrolet Impala 3.6L V6 LFX · AWD

What this code means

The EGR system flow is not within expected parameters.

Symptoms

  • Check Engine Light
  • Rough idle
  • Pinging/knocking
  • Increased NOx emissions
  • Failed emissions test

Common causes

  • Clogged EGR passages
  • Faulty EGR valve
  • EGR valve stuck closed
  • Carbon buildup
  • Vacuum line issue

Diagnostic steps

  1. Test EGR valve operation
  2. Check EGR passages for carbon buildup
  3. Test vacuum supply to EGR valve
  4. Monitor EGR position with scan tool
  5. Inspect EGR tube

Repair notes

Clean EGR valve and passages. Replace EGR valve if stuck or faulty.

Other Powertrain codes on this vehicle

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