Diagnostic Method: Notes

0.04-inch Diagnosis

Mode Z: (Purge control solenoid valve opening failure diagnosis) 

When performing the leakage diagnosis of the EVAP system, the purge control solenoid valve must operate properly. Therefore, mode Z is used to diagnose a stuck open condition of the purge control solenoid valve by monitoring the tank pressure.

Note that if a purge control solenoid valve stuck open fault is detected, the EVAP system leakage diagnosis is cancelled.

• Purge Control Solenoid Valve Stuck Open Diagnosis 

DTC 

P0457 Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)

Purge control solenoid valve stuck open diagnosis is performed in mode Z as shown in the figure below.

• Purge Control Solenoid Valve Function Diagnosis 

DTC 

P0457 Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)

Purge control solenoid valve functional diagnosis is performed by monitoring the tank pressure in mode Z.

Normality Judgment 

Make OK judgment 3 seconds after Mode Z starts, and change to Mode A if OK.

Judgment Value 

Malfunction Criteria	Threshold Value	DTC
(Tank pressure when Mode Z started) -(Tank pressure when Mode Z finished)	≤ 0.4 kPa (3 mmHg, 0.12 inHg)	P0457

• Normal 
  Fig 2: Purge Control Solenoid Valve Diagram - Mode Z

  Courtesy of SUBARU OF AMERICA, INC.
• evptez - evptezha ≤ 0.4 kPa (3.0 mmHg, 0.12 inHg)

Normal when above is established

Abnormality Judgment 

If OK judgment cannot be made, extend Mode Z 16 seconds more, and Judge as NG when the malfunction criteria below are met.

Judgment Value 

Malfunction Criteria	Threshold Value	DTC
(Tank pressure when Mode Z started) - (Tank pressure when Mode Z finished)	> 0.6 kPa (4.5 mmHg, 0.18 inHg)	P0457
Tank pressure when Mode Z started	≤ 1.43 kPa (10.7 mmHg, 0.42 inHg)
Time of 2 l  or more fuel no sloshing	≥ 40 seconds

Time Needed for Diagnosis:  16 seconds

Malfunction Indicator Light Illumination:  Illuminates when malfunction occurs in 2 continuous driving cycles.

When judgment for purge control solenoid valve stuck open NG is made, end the evaporative diagnosis. Cancel the evaporative diagnosis when the OK/NG judgment for drain valve stuck closed and purge control solenoid valve stuck open cannot be made in Mode Z.

• evptezini, evptez ≤ 1.43 kPa (10.7 mmHg, 0.42 inHg)
• evptez - evptezha ≤ 0.6 kPa (4.5 mmHg, 0.18 inHg)
• No fuel sloshing of over 2 l  (0.79 US gal, 0.67 lmp gal) lasts for more than 40 seconds. Judge as normal when all are established.

• Leak Diagnosis 

DTC 

P0441 Purge control solenoid valve 2 close diagnosis

P0442 Evaporative Emission Control System Leak Detected (Small Leak)

P0457 Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)