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Inspection Mode V

DTC DESCRIPTION - INSPECTION MODE V

DTC Description & trouble part Condition Number of driving cycles on the detecting condition
P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD BANK 1 -  2
WARNING: When performing inspection mode V on a public road, pay sufficient attention to the traffic condition and give the highest priority to safe driving.
NOTE: Perform the inspection mode after warming up the engine except that the engine coolant temperature at engine start is specified.
  1. Check that the battery voltage is 12 V or more and fuel remains approx. half [20 - 40 L (5.3 - 10.6 US gal, 4.4 - 8.8 Imp gal)].
  2. Using the Subaru Select Monitor, perform the clear memory of [Engine Control System]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
  3. Drive according to the drive pattern described below.
    G16348860Courtesy of SUBARU OF AMERICA, INC.
    (1) Vehicle speed 0 km/h (0 MPH)
    (2) Vehicle speed 60 km/h (37 MPH)
    (A) Start the engine.
    (B) Idle the engine for at least five minutes.
    (C) Accelerate the vehicle to 60 km/h (37 MPH).
    (D) Using the Subaru Select Monitor, check the [Catalyst Temperature (B1-S1)] value and drive at a constant speed of 60 km/h (37 MPH) until 500°C (932°F) is reached.
    (E) From the state where [Catalyst Temperature (B1-S1)] value is 500°C (932°F) or more and the vehicle speed is 60 km/h (37 MPH), change the accelerator opening angle to 0% to perform fuel cut for at least 5 seconds.
    (F) Drive the vehicle with 10 to 20 % of the accelerator opening angle for at least 10 seconds.
    (G) Accelerate the vehicle to 60 km/h (37 MPH).
    (H) From the state where [Catalyst Temperature (B1-S1)] value is 500°C (932°F) or more and the vehicle speed is 60 km/h (37 MPH), change the accelerator opening angle to 0% to stop the vehicle with fuel cut for at least 5 seconds.
    (I) Idle the engine for 20 seconds or more.
    NOTE:
    • The condition of acceleration or constant driving can be changed according to different traffic conditions.
    • If diagnostic values have not been input after driving, repeat the cycle from step (C) without stopping the engine.
  4. Read the pending code using the Subaru Select Monitor or general scan tool. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
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