Diagnostic Method

Courtesy of SUBARU OF AMERICA, INC.

Mode	Explanation of Mode	Diagnosis Period
A	Vacuum pump operation confirmation and characteristics stability	7 s
B	Measurement of reference pressure for setting the target negative pressure	350 s
C	Switching valve operation confirmation	12 s
D	Pipe clogging diagnosis and leak pressure measurement	900 s
D2	Pipe clogging diagnosis of high-pressure line	60 s
E	Reference pressure measurement for judgment	50 s

Courtesy of SUBARU OF AMERICA, INC.

Mode A (Vacuum pump operation confirmation and characteristics stability) 

Purpose: Detect the vacuum pump operation trouble.

Judge as NG when the following conditions are established.

Judge as OK if the following conditions are not established, and warm up for five minutes to stabilize the vacuum pump characteristics.

Malfunction Criteria	Threshold Value	DTC
Pressure sensor output value	> -224 Pa (-1.7 mmHg, -0.1 inHg)	P2404

Mode B (Measurement of reference pressure for setting the target negative pressure) 

Judgment 1

Purpose: Judge the reference pressure stability.

Judge as NG when the following conditions are established.

Judgment 2

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

Judge as NG when the following conditions are established.

Malfunction Criteria	Threshold Value	DTC
<Judgment 1> |Pressure sensor maximum output value - Pressure sensor minimum output value|	> 493 Pa (3.7 mmHg, 0.1 inHg)	P2404
or <Judgment 2> Reference pressure for setting the target negative pressure	< Value of Map 2	P2404
or <Judgment 3> Reference pressure for judgment	> Value of Map 3	P2404

Barometric pressure (kPa (mmHg, inHg))	70 (525, 20.7)	80 (600, 23.6)	90 (675, 26.6)	100 (750, 29.5)
Reference pressure for setting the target negative pressure (Pa (mmHg, inHg))	-3972 (-29.8, -1.2)	-4079 (-30.6, -1.2)	-4186 (-31.4, -1.2)	-4292 (-32.2, -1.3)

Barometric pressure kPa (mmHg, inHg)	70 (525, 20.7)	80 (600, 23.6)	90 (675, 26.6)	100 (750, 29.5)
Reference pressure for setting the target negative pressure (Pa (mmHg, inHg))	-942 (-7.1, -0.3)	-1048 (-7.9, -0.3)	-1155 (-8.7, -0.3)	-1262 (-9.5, -0.4)

Mode C (Switching valve operation confirmation) 

Purpose: Measure the pressure increase when switching valve is changed from open to close, and detect the stuck to open/close malfunctions of the switching valve.

Judge as NG when the following conditions are established.

Malfunction Criteria	Threshold Value	DTC
Pressure sensor output value - Reference pressure for setting the target negative pressure	< 224 Pa (1.7 mmHg, 0.1 inHg)	P2404

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

Malfunction Criteria	Threshold Value	DTC
<Phase D>		P1451
When reaching to the target negative pressure	≤ 27000 ms
<Phase D2>		P04AF
Reference pressure for judgment of the target negative pressure	≥-667 Pa (-5.004 mmHg, -0.197 inHg)
<Large leak (0.04 inch)>		P0455
Leak pressure	≥ Value of Map 6
<Very small leak (0.02 inch)>		P0456
Leak pressure	> Reference pressure of 0.018 inch (Pa) and < Map6 (Pa)

Reference pressure (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

Time needed for diagnosis:  24 min

Mode E (Measurement of reference pressure for judgment) 

Judgment 1

Purpose: Judge the reference pressure stability.

Judge as NG when the following conditions are established.

Judgment 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.

Judgment 3

Purpose: Judge the presence of evaporative emission system leak.

Judge as NG when the following conditions are established.

Malfunction Criteria	Threshold Value	DTC
<Judgment 1> |Pressure sensor maximum output value - Pressure sensor minimum output value|	> 493 Pa (3.7 mmHg, 0.1 inHg)	P2404
or <Judgment 2> Reference pressure for judgment	< Value of Map 4 or > Value of Map 5	P2404
or <Judgment 3> |Reference pressure for setting the target negative pressure - Reference pressure for judgment|	> 941 Pa (7.1 mmHg, 0.3 inHg)	P2404

Barometric pressure (kPa (mmHg, inHg))	70 (525, 20.7)	80 (600, 23.6)	90 (675, 26.6)	100 (750, 29.5)
Reference pressure for judgment (kPa (mmHg, inHg))	-4.5 (-34.02, -1.3)	-4.6 (-34.815, -1.4)	-4.7 (-35.618, -1.4)	-4.9 (-36.42, -1.4)

Barometric pressure (kPa (mmHg, inHg))	70 (525, 20.7)	80 (600, 23.6)	90 (675, 26.6)	100 (750, 29.5)
Reference pressure for judgment (kPa (mmHg, inHg))	-0.8 (-6.18, -0.2)	-0.9 (-6.983, -0.3)	-1 (-7.785, -0.3)	-1.1 (-8.58, -0.3)

Time needed for diagnosis:  24 min

Malfunction will be confirmed at next engine start.

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