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Contents

Section: Testing & Diagnostics

Engine Controls - Engine (Diagnostics) (H4SO)

Engine Controls - Engine (Diagnostics) (H4DOTC)

All sections

Diagnostic Trouble Code (DTC) Detecting Criteria (H4SO): Overview Subaru Forester SG рестайлинг

Testing & Diagnostics 6 illustrations ~1429 words

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.

ECM OPERATION AT DTC SETTING

Memorize the freeze frame data. (For test mode $02)

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Memorize the freeze frame data. (For test mode $02)

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Memorize the freeze frame data. (For test mode $02)

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Memorize the freeze frame data. (For test mode $02)

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Pressure Control Solenoid Valve

PCV controls the fuel tank pressure to be equal to the atmospheric air pressure. Normally, the solenoid is set to OFF. The valve opens and closes mechanically in accordance with the pressure difference between tank and atmospheric air, or tank and canister.

The valve is forcibly opened by setting the solenoid to ON at the time of diagnosis.

Identifying Pressure Control Solenoid Valve Components. Scheme 1

Scheme 1: Identifying Pressure Control Solenoid Valve Components

Valve Operation and Air Flow

In the figure below, divided by the diaphragm, the part above X is charged with atmospheric air pressure, and the part below X is charged with tank pressure. Also, the part above Y is charged with tank pressure, and the part below Y is charged with canister pressure.

If the atmospheric air pressure port is A, tank pressure port is B, and canister pressure port is C, the air flows according to pressure difference from each port as shown in the table below.

Identifying Pressure Control Solenoid Valve Air Flow Diagram. Scheme 2

Scheme 2: Identifying Pressure Control Solenoid Valve Air Flow Diagram

Condition of pressure	Flow
A < B (solenoid OFF)	B-->C
B < C (solenoid OFF)	C-->B
Solenoid ON	B--><--C

CONDITION OF PRESSURE AND FLOW REFERENCE

Identifying Pressure Control Solenoid Valve Air Flow Diagram (When A < B (Solenoid OFF)). Scheme 3

Scheme 3: Identifying Pressure Control Solenoid Valve Air Flow Diagram (When A < B (Solenoid OFF))

When B < C (Solenoid OFF)

Identifying Pressure Control Solenoid Valve Air Flow Diagram (When B < C (Solenoid OFF)). Scheme 4

Scheme 4: Identifying Pressure Control Solenoid Valve Air Flow Diagram (When B < C (Solenoid OFF))

When Solenoid is ON

Identifying Pressure Control Solenoid Valve Air Flow Diagram (When Solenoid ON)). Scheme 5

Scheme 5: Identifying Pressure Control Solenoid Valve Air Flow Diagram (When Solenoid ON))

Drain Valve

Drain valve controls the ambient air to be introduced to the canister.

Identifying Drain Valve. Scheme 6

Scheme 6: Identifying Drain Valve

Memorize the freeze frame data. (For test mode $02)
Memorize the diagnostic value and trouble standard value. (For test mode $06)

Memorize the freeze frame data. (For test mode $02)

ECM and TCM are connected by high speed CAN.

(Common Specifications)

CAN Protocol 2.0 B (Active)

Frame Format: 11 Bit ID Frame (Standard Frame)

(High speed CAN)

Conforms to ISO11898

Communication Speed: 500 kbps

Memorize the freeze frame data. (For test mode $02)

The atmospheric pressure sensor is built into the ECM.

Memorize the freeze frame data. (For test mode $02)

The atmospheric pressure sensor is built into the ECM.

Memorize the freeze frame data. (For test mode $02)

The atomospheric pressure sensor is built into the ECM.

Memorize the freeze frame data. (For test mode $02)

Diagnostic Trouble Code (DTC) Detecting Criteria (H4SO): Overview Subaru Forester SG рестайлинг

COMPONENT DESCRIPTION

ECM OPERATION AT DTC SETTING

Identifying Pressure Control Solenoid Valve Components. Scheme 1

Identifying Pressure Control Solenoid Valve Air Flow Diagram. Scheme 2

Identifying Pressure Control Solenoid Valve Air Flow Diagram (When A < B (Solenoid OFF)). Scheme 3

Identifying Pressure Control Solenoid Valve Air Flow Diagram (When B < C (Solenoid OFF)). Scheme 4

Identifying Pressure Control Solenoid Valve Air Flow Diagram (When Solenoid ON)). Scheme 5

Identifying Drain Valve. Scheme 6

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