1. Operation

The  main  control  device  is  the  crankcase  ventilation  (PCV)
valve.  purged  crankcase  ventilation  valve  calculate  the
channeling air flow according to manifold vacuum signal. Lower
crankcase ventilation valve parts below the O-ring are exposed
to a vacuum in the intake manifold, parts located between the
lower and upper O-ring are exposed to the crankcase gases.
Purged  crankcase  ventilation  valve  allows  some  internal
vacuum pressure through the valve orifice, and form the low-
pressure  condition  inside  the  crankcase.  The  channeling
crankcase gas is then sucked into intake system and burnt in
the normal combustion process. the channeling gas entering
into the intake manifold must be accurately controlled in order
to  maintain  idle  quality.  Must  use  the  correct  and  proper
calibration  of  the  crankcase  ventilation  valve.  Relationship
between the Channeling air flow and engine manifold vacuum
is shown in the table below:

Manifold

Vacuum

Purged

Crankcase

Ventilation Valve

Opening

Channeling Air

Flow

Low

Large

High

High

Small

Low

2. The Consequences Of Abnormal Operation

Valve or hose blockage may lead to the following conditions:

–

Poor engine idling.

–

Engine stalls or engine idle speed is too low.

–

Engine crankcase pressure is too high.

–

Engine oil leaks.

–

Engine oil enters into the air filter.

–

Engine has sludge.

–

Engine oil consumption is high.

–

Excessive exhaust emissions.

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2.4.3 System Working Principle
2.4.3.1 Heated Type Oxygen Sensor Working
Principle

–

Oxygen sensor's sensing element is a porous ceramic tube,
the outer wall surrounded by the engine exhaust and inside
exposed  to  atmosphere.  Sensing  ceramic  wall  is  a  solid
electrolyte  containing  an  electric  heating  tube.  When  the
sensor ceramic tube temperature reaches 350°C (662 ºF ),
it will have a solid electrolyte properties.

–

Oxygen sensor's senses ceramic oxygen ion concentration
inside and outside difference and sends it out as a voltage
signal.

–

The  output  voltage  level  is  due  to  internal  electronic
ceramic tubes movement.

–

Meet  EOBD  vehicles  self  inspect  whether  the  sensor
information is accurate.

–

Heated resistor resistance at room temperature is 2.5-4.9
Ω.

Note

–

During  the  oxygen  sensor  repair  procedure,  it  is
prohibited  to  use  cleaning  agent,  oily  liquids  or
volatile solids.

–

After the replacement of oxygen sensor, apply a layer
of anti-rust oil to oxygen sensor threads to prevent
rust.  Oxygen  sensors  have  electrical  cables.  The
other  end  of  electrical  cable  is  a  connector.  The
external packaging is anti-fire sleeve. A new oxygen
sensor will be coated with anti-rust oil on the threads,
during installation do not remove these anti-rust oil.

2.4.3.2  Canister  Solenoid  Valve  Working
Principle

1. Canister  solenoid  valve  consists  of  the  electromagnetic

coil, armature and valves so on. Inlet port has a filter.

2. On one hand, air flow through the Canister solenoid valve

is  related  to  ECM  output  to  the  Canister  solenoid  valve
electrical pulse duty cycle; on the other hand, it is related
to the pressure difference between the Canister solenoid
valve inlet port and outlet port. When there is no electrical
pulses, the Canister solenoid valve will be turned off.

3. ECM provides signals to control the Canister solenoid valve

power  according  to  various  engine  sensor  signals,  and
indirectly controls the flow of the clean air.

4. When the engine coolant temperature, engine running time

and engine load etc. meet the preset requirements, ECM
will instruct Canister solenoid valve to start working. In the
following situations canister solenoid valve will not work:

•

Engine cold start.

•

Engine coolant temperature is relatively low.

•

Engine idle.

•

Engine load is high.

•

Important sensor system faults.

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2.4.4 Component Locator
2.4.4.1 Canister Location

2

1

FE11-2025b

Legend

1. Canister Assembly

2. Canister Ventilation Filter

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2.4.4.2 Canister Solenoid Valve Location

FE02-2026b

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Engine