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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 P0455: EVAP System (CPC) Leak Detected (Large Leak) >> Diagnostic Method >> Mode D (Clogging Of Pipe Diagnosis And Leak Pressure Measurement)
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Mode D (Clogging Of Pipe Diagnosis And Leak Pressure Measurement)

  1. Clogging of pipe 

    Purpose: Measure the time required for the evaporative emission system to reach the target negative pressure by the vacuum pump, and detect the clogging of pipe trouble.

    Judge as clogging of pipe malfunction if the evaporative emission system reaches to the target negative pressure within the specified time.

  2. Leak pressure measurement 

    Purpose: Measure the pressure (leak pressure) when the evaporative emission system becomes the negative pressure by the vacuum pump.

    Store the pressure as a leak pressure while the following conditions are met.

    Phase D

JUDGMENT VALUE SPECIFICATION

Malfunction Criteria Threshold Value DTC
Time required to reach to the target negative pressure 25216ms or less P1451
<Large leak (0.04 inch)>   P0455
Leak pressure Value of Map4 or more  
<Very small leak (0.02 inch)>   P0456
Leak pressure More than 0.018 inch reference pressure (Pa) and Less than value of Map6  
MAP 4 SPECIFICATION

Reference pressure for judgment (Pa) -4856 -4000 -2750 -1500 -824
Threshold Value (Pa) -1785 -1463 -991 -520 -265

Formula for threshold value = Reference pressure x 0.377 - 0.341