Mazda B-Series 1997 Workshop Manual page 374

OUTLINE
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COMPONENT
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FUNCTION
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REMARK
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Orifice tube assembly
(for EGR)
Provides flow path for
EGR
to intake
manifold.
Contains metering orifice arid two pressure
pick-up tubes. Internally located orifice creates a
measurable pressure drop across it as EGR valve
opens and closes.
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O g ~ t test mode OTM aids in servicing output actuators
associated with PCM. It energizes and
de-energizes most of system output
actuators on command.
Output shaft speed
(OSS) sensor
Monitors output shaft speed and sends a
signal to PCM for EPC and shifVtorque
converter scheduling.
Magnetic pick-up type.
Overdrive drum
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Monitors overdrive drum speed and sends a Magnetic pick-up type.
speed (ODs) sensor signal to PCM.
Parameter
identification (PID)
PID is certain data values, analog and digital
inputs and outputs, calculated value, and
system status information. PID can be
accessed from scan tool or NGS tester.
PlDs listed on Generic OBC) II PID list must be
accessed from all scan tools.
Positive crankcase
ventilation (PCV)
Cycles crankcase gases back through PCV regulates amount of ventilating air and
engine, where they are burned. blow-by gas to intake manifold and prevents
from traveling into crankcase.
PSR is used as a redundant seal to PSR is a spring operated closing plate at bottom of
evaporative system in case fuel filler cap
housing located in fuel filler neck.
missing.
Positive seal retainer
(PSR)
Powertrain control
module (PCM)
PCM receives input from sensors and other
electronic components. Based on data
received and programmed into memory,
PCM generates output signals to control
various relays, solenoids and actuators.
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Supplies current to output devices and PCM.
Monitors hydraulic pressure and sends
signal to PCM.
PCM controls the following:
1.
Adjusts idle rpm
2. Adjusts transmission line pressure during
increased engine load.
PCM has a 104-pin electrical connector.
PCM power relay
Power steering
pressure (PSP) switch
(2.3L only)
PSP switch is a normally closed switch that opens
as the hydraulic pressure increases.
Profile ignition
pickup (PIP) signal
PCM generates an internal PIP signal from
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PIP signal circuit is enclosed In PCM.
crankshaft position sensor signal. PIP signal
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is used to calculate SPOUT signal and to
supply a clean, inverted signal for
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tachometer operation.
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Monitors vapor flow through EVAP solenoid
and sends signal to PCM. PCM sends output
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signal to solerioid based on flow cond~tions.
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Purge flow sensor
Shift solenoids
(SS1, SS2, SS3, SS4)
Provides gear selection by controlling
transmission fluid pressure of shift valve.
PCM outputs driver signals to solenoids.
Use normally closed and OWIOFF style solenoids.
When solenoids are ON, holds pressure. When
solenoids are OFF, exhausts pressure.
Spark output signal
(SPOUT)
SPOUT is a pulse width modulated digital
signal which is used internally by PCM as a
calculated spark target.
SPOUT signal circuit is enclosed in PCM
Three-way catalytic
(TWC) converter
Catalyzes oxidation reactions of unburned
hydrocarbons and carbon monoxide, and
reduction reaction of oxides of nitrogen.
Three-way conversion only occurs with
airlfuel near stoichiometry.
Contains either platinum and rhodium or palladium
and rhodium. Catalyst is a rnaterial that remains
unchanged when it initiates and increases speed
of a chemical reaction. Catalyst will enable a
chemical reaction to occur at lower temperature.
Throttle body Meters air to engine during idle, part throttle,
and wide open throttle conditions. IAC
solenoid and throttle position sensor are
mounted on throttle body.
SealanVcoating on bore (must not be cleaned).
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