Subaru 2006 Legacy, Manual

Page: 1235 / 4302

GD(H4SO U5)-9
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
2. Diagnostic Trouble Code (DTC) Detecting Criteria
A: DTC P0026 INTAKE VALVE CONTROL SOLENOID CIRCUIT RANGE/PER-
FORMANCE (BANK 1)
1. OUTLINE OF DIAGNOSIS
Detect NG when having either Low NG or High NG.
A variable valve lift diagnosis oil pressure switch is installed for diagnosis. It is possible to determine whether
the intake valve is in high mode (increase the amount of lift) or in low mode (suppressing the amount of lift)
when the variable valve lift diagnosis oil pressure switch is turned OFF or ON.
• Normal
• Low NG
When the variable valve lift diagnosis oil pressure switch remains ON even though the intake valve tried to
enter high mode (oil switching solenoid valve duty is large), this is judged as a Low NG.
• High NG
When the variable valve lift diagnosis oil pressure switch remains OFF even though the intake valve tried to
enter low mode (oil switching solenoid valve duty is small), this is judged as a High NG.
2. COMPONENT DESCRIPTION
The variable valve lift system optimizes the intake valve lift by switching between the low lift cam and the high
lift cam according to the engine speed. The amount of intake valve lift is varied by controlling the oil switching
solenoid valve duty according to signals from the ECM.
3. ENABLE CONDITION
4. GENERAL DRIVING CYCLE
Perform the diagnosis continuously 6 seconds after engine start while variable valve lift is being controlled.
Oil switching solenoid valve duty Intake valve
Variable valve lift diag-
nosis oil pressure
switch
Large High mode OFF
Minimum Low mode ON
Secondary Parameters Enable Conditions
Battery voltage
≥
10.9 V
After engine starting
≥
6 sec.
Engine oil temperature
≥
15°C (59°F)
Variable valve lift control Operating
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