LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2021 >> Legacy Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (2.5L) (Diagnostics) (2 Of 4) >> Diagnostic Procedure With Diagnostic Trouble Code (DTC) >> DTC P0455: EVAP System (CPC) Leak Detected (Large Leak) >> General Description >> Diagnostic Method >> <Mode E (Measurement of reference pressure for judgment)>
April 5, 2026: LEMON Manuals is launched! Read the announcement.

<Mode E (Measurement of reference pressure for judgment)>

Diagnosis 1

Purpose: Judge the reference pressure stability.

Judge as NG when the following conditions are established.

Diagnosis 2

Purpose: Judge whether the reference pressure is within the normal range, and detect the vacuum pump and orifice malfunctions. Judge the vacuum pump performance stability.

Judge as NG when the following conditions are established.

Diagnosis 3

Purpose: Judge the presence of evaporative emission system leak.

Judge as NG when the following conditions are established.

JUDGMENT VALUE - DIAGNOSIS 1

Malfunction Criteria Threshold Value DTC
|Pressure sensor maximum output value - Pressure sensor minimum output value| More than 314Pa (2.355mmHg, 0.1 inHg) P2404
JUDGMENT VALUE - DIAGNOSIS 2

Malfunction Criteria Threshold Value DTC
Reference pressure for judgment Less than value of Map5 Or, More than value of Map6 P2404
JUDGMENT VALUE - DIAGNOSIS 3

Malfunction Criteria Threshold Value DTC
|Reference pressure for setting the target negative pressure - Reference pressure for judgment| More than 0.9kPa (7.058mmHg, 0.3 inHg) P2404
BAROMETRIC PRESSURE - MAP5

Barometric pressure (kPa (mmHg, inHg)) 70 (525, 20.7 inHg) 80 (600, 23.6 inHg) 90 (675, 26.6 inHg) 100 (750, 29.5 inHg)
Reference pressure for judgment (kPa (mmHg, inHg)) -4.5 (-34.020, -1.3 inHg) -4.6 (-34.815, -1.4 inHg) -4.7 (-35.618, -1.4 inHg) -4.9 (-36.420, -1.4 inHg)
BAROMETRIC PRESSURE - MAP6

Barometric pressure (kPa (mmHg, inHg)) 70 (525, 20.7 inHg) 80 (600, 23.6 inHg) 90 (675, 26.6 inHg) 100 (750, 29.5 inHg)
Reference pressure for judgment (kPa (mmHg, inHg)) -0.8 (-6.180, -0.2 inHg) -0.9 (-6.983, -0.3 inHg) -1 (-7.785, -0.3 inHg) -1.1 (-8.580, -0.3 inHg)

Time needed for diagnosis:  23 min

Confirm the malfunction at next engine start.

Malfunction indicator light illumination:  Illuminates when malfunction occurs in 2 continuous driving cycles.