Lexus SC300 / Lexus SC400. Service manual — part 714

SCHEMATIC DRAWING

EC–4

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EMISSION CONTROL SYSTEMS

Description

PREPARATION

SST (SPECIAL SERVICE TOOL)

RECOMMENDED TOOLS

EQUIPMENT

Part Name

Note

Engine tune–up tester

Engine speed

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EMISSION CONTROL SYSTEMS

Preparation

EC–5

POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM

DESCRIPTION

To reduce HC emission, crankcase blow–by gas (HC) is routed through the PCV valve to the air intake cham-

ber for combustion in the cylinders.

OPERATION

EC–6

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EMISSION CONTROL SYSTEMS

Positive Crankcase Ventilation (PVC) System

INSPECTION OF PCV VALVE

1.

REMOVE PCV VALVE
(a) Disconnect the PCV hose from the PCV valve.
(b) Remove the PCV valve.

2.

INSTALL CLEAN HOSE TO PCV VALVE

3.

INSPECT PCV VALVE OPERATION
(a) Blow air into the cylinder head side, and check that air

passes through easily.

CAUTION: Do not suck air through the valve. Petroleum
substances inside the valve are harmful.

(b) Blow air into the air intake chamber side, and check that

air passes through with difficulty.

If operation is not as specified, replace the PCV valve.

4.

REMOVE CLEAN HOSE FROM PCV VALVE

5.

REINSTALL PCV VALVE

INSPECTION OF PCV HOSE AND
CONNECTIONS

VISUALLY INSPECT HOSE, CONNECTIONS AND GASKETS

Check for cracks, leaks or damage.

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EMISSION CONTROL SYSTEMS

Positive Crankcase Ventilation (PVC) System

EC–7