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Diagnostic Trouble Code (DTC) Detecting Criteria (H4DOTC): Overview Subaru Forester SH

Testing & Diagnostics 4 illustrations ~185 words

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.

Scheme 174

Scheme 174: Valve Operation and Air Flow
Condition of pressureFlow
A < B (solenoid OFF)B --> C
B < C (solenoid OFF)C --> B
Solenoid ONB <--> C

MAP SPECIFICATION

Scheme 175

Scheme 175: When A < B (solenoid OFF)

Scheme 176

Scheme 176: When B < C (solenoid OFF)

Scheme 177

Scheme 177: When Solenoid is ON

COMPONENT DESCRIPTION

Vehicle speed signals are taken in to the ABS control module and hydraulic control unit, and normal/erroneous data of the ABS wheel speed sensor is received by CAN communication from the ABS control module and hydraulic control unit.

ECM, TCM, VDC CM and body integrated unit 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