Nissan Altima 2007-2012 Service Manual: Positive crankcase ventilation
Description
This system returns blow-by gas to the intake manifold.
The positive crankcase ventilation (PCV) valve is provided to conduct crankcase blow-by gas to the intake manifold.
During partial throttle operation of the engine, the intake manifold sucks the blow-by gas through the PCV valve.
Normally, the capacity of the valve is sufficient to handle any blow-by and a small amount of ventilating air.
The ventilating air is drawn from the air inlet tubes into the crankcase. In this process the air passes through the hose connecting air inlet tubes to rocker cover.
Under full-throttle condition, the manifold vacuum is insufficient to draw the blow-by flow through the valve.
The flow goes through the hose connection in the reverse direction.
On vehicles with an excessively high blow-by, the valve does not meet the requirement. This is because some of the flow will go through the hose connection to the air inlet tubes under all conditions.
Component Inspection
1.CHECK PCV VALVE
With engine running at idle, remove PCV valve from rocker cover. A properly working valve makes a hissing noise as air passes through it. A strong vacuum should be felt immediately when a finger is placed over valve inlet.
Is the inspection result normal? YES >> INSPECTION END
NO >> Replace PCV valve.
On board refueling vapor recovery
(ORVR)
Description
From the beginning of refueling, the air and vapor inside the fuel tank go
through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by t ...
Refrigerant pressure sensor
Description
The refrigerant pressure sensor is installed at the condenser of the air
conditioner system. The sensor uses an
electrostatic volume pressure transducer to convert refrigerant pressur ...
Other materials:
Symptom diagnosis
SYSTEM SYMPTOM
Symptom Table
The diagnostics item numbers show the sequence for inspection. Inspect in
order from item 1.
...
Precaution
Supplemental Restraint System (SRS) "AIR B
AG" and "SEAT BELT PRE-TENSIONER"
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT
PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the
driver and fron ...
Mixture ratio self-learning value
clear
Description
This describes show to erase the mixture ratio self-learning value. For the
actual procedure, follow the instructions
in “Diagnosis Procedure”.
Special Repair Requirement
1.START
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CO ...
