LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2018 >> Crosstrek Base, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostics) (2 Of 4) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0400: EGR "A" Flow >> Notes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0400: EGR "A" Flow: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Trouble symptom: 

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4PO)>Basic Diagnostic Procedure>PROCEDURE .
  1. CHECK DATA MONITOR  .
    1. Start the engine.
    2. Using the Subaru Select Monitor or a general scan tool, read the value of [Mani. Absolute Pressure].

      Data Monitor 

      NOTE:
      • SUBARU SELECT MONITOR For detailed operation procedures, refer to "Data Monitor". Ref. to ENGINE (DIAGNOSTICS) (H4DO)>DATA MONITOR .
      • General scan tool For detailed operation procedures, refer to the general scan tool operation manual.

    Is the value of [Mani. Absolute Pressure] 53.3 kPa (400 mmHg, 15.75 inHg) or more?

    Yes:  Make sure that the EGR control valve, manifold absolute pressure sensor and throttle body are installed securely.

    No:  Go to  2.

  2. CHECK EGR CONTROL VALVE  .

    Remove the EGR control valve.

    Are there any holes, clogged lines or foreign matters in the EGR system?

    Yes:  Repair the EGR system.

    No:  Replace EGR control valve. Ref. to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (H4DO)>EGR CONTROL VALVE .