Mazda X-5. Manual — part 43

CONTROL SYSTEM

01–40–45

01–40

THROTTLE POSITION (TP) SENSOR FUNCTION [LF]

E5U014018910N01

• Detects the throttle valve opening angle.

End Of Sie

THROTTLE POSITION (TP) SENSOR CONSTRUCTION/OPERATION [LF]

E5U014018910N02

• The sensor is built into the throttle body and

detects the throttle valve opening angle.

• The Hall element design has been adopted for the

sensor.

• A non contact type sensor has been adopted to

improve durability.

• The TP sensor is composed of the main sensor

and sub sensor, and detects the throttle valve
opening angle with these two sensors (main and
sub).

• Even if a malfunction occurs in either one of the

sensors, the detection is performed with a normal
sensor and drive-by-wire control is maintained.

• If both the MAIN and SUB sensors for the TP

sensor malfunction, signals necessary for the drive-by-wire control are not input to the PCM and the drive-by-
wire control is disabled.

• However, even though the drive-by-wire control is disabled, the throttle valve opening angle necessary for

minimum driving is maintained mechanically.

End Of Sie

TP SENSOR

THROTTLE
VALVE

THROTTLE
BODY

E5U140ZN5853

PCM

CPU
CPU

HALL ELEMENT
SENSOR

MAGNET

TP SENSOR

SUB

MAIN

LOW

HIGH

OUTPUT
VOLTAGE

SMALL

TP SENSOR No.2

TP SENSOR No.1

LARGE

THROTTLE

OPENING ANGLE

E5U140ZN5854

CONTROL SYSTEM

01–40–46

ACCELERATOR PEDAL POSITION (APP) SENSOR FUNCTION [LF]

E5U014041609N01

• Detects how much the accelerator pedal is depressed.

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ACCELERATOR PEDAL POSITION (APP) SENSOR CONSTRUCTION/OPERATION [LF]

E5U014041609N02

• The sensor is installed on the accelerator pedal and detects how much the accelerator pedal is depressed.

• The Hall element design has been adopted on the

sensor.

• A non contact type sensor has been adopted to

improve durability.

• The APP sensor is composed of the main sensor

and sub sensor, and detects the accelerator
opening angle with these two sensors (main and
sub).

• The main sensor output a duty signal, and the sub

sensor output a voltage signal.

• Even if a malfunction occurs in either one of the

sensors, the detection is performed with a normal
sensor drive-by-wire control is maintained.

• If both the main and sub sensors for the APP

sensor malfunction, signals necessary for the drive-by-wire control are not input to the PCM and the drive-by-
wire control is disabled.

• However, even though the drive-by-wire control is disabled, the throttle valve opening angle necessary for

minimum driving is maintained mechanically.

End Of Sie

APP
SENSOR

ACCELERATOR PEDAL

E5U140ZW5306

PCM

CPU

CPU

MAGNET

APP SENSOR

MAIN SENSOR

SUB SENSOR

HIGH

LOW

OUTPUT
VOLTAGE

SMALL

LARGE

ACCELERATOR PEDAL
DEPRESSION AMOUNT

HALL ELEMENT
SENSOR

MAIN

SUB

CHU0140S057

CONTROL SYSTEM

01–40–47

01–40

MASS AIR FLOW (MAF) SENSOR FUNCTION [LF]

E5U014013215N01

• Detects the air amount (mass airflow amount) inducted into the engine.

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MASS AIR FLOW (MAF) SENSOR CONSTRUCTION/OPERATION [LF]

E5U014013215N02

• Built into the intake air temperature sensor.

• Converts the mass intake airflow amount to

voltage.

• When the temperature of the metal decreases,

the resistance decreases. Using this
characteristic, the hot wire captures heat from the
flow of intake air and converts the intake airflow
amount to voltage.

• The cold wire converts intake air density to

voltage from the ambient temperature of the cold
wire, using the characteristic of air whereby the
intake air density decreases due to the increase
in intake air temperature.

• The voltages obtained by the hot wire (intake

airflow amount) and the cold wire are compared
and the electric potential becomes stable by
supplying the difference in voltage to the
transistor. The voltage supplied to the hot wire is
output as the mass intake airflow amount.

End Of Sie

HEATED OXYGEN SENSOR (HO2S) FUNCTION [LF]

E5U014018860N01

• Front HO2S: the wide-range air/fuel ratio sensor, which can linearly detect the oxygen concentration (air/fuel

ratio of the air-fuel mixture) in the exhaust gas in all ranges, from lean to rich, is used on the front HO2S.

• Rear HO2S: detects the oxygen concentration in the exhaust gas.

• A heater has been adopted, allowing stable detection of the oxygen concentration even when the exhaust gas

temperature is low.

End Of Sie

MAF SENSOR

PCM

COLD
WIRE

HOT
WIRE

COMPARISON
CIRCUIT

FIXED
RESISTANCE

CPU

MAF SENSOR
VOLTAGE
CHARACTERISTIC

VOLTAGE

MASS AIR

FLOW AMOUNT

LARGE

SMALL

LOW

HIGH

E5U140ZN5852

CONTROL SYSTEM

01–40–48

HEATED OXYGEN SENSOR (HO2S) CONSTRUCTION/OPERATION [LF]

E5U014018860N02

• Installed on the front of the WU-TWC, and back of

the TWC.

Front HO2S

• The wide-range air/fuel ratio sensor is a limited current type sensor, and can detect the oxygen concentration

(air/fuel ratio of the air-fuel mixture) in the exhaust gas in all ranges, from lean to rich.

• A heater is built into the sensor to facilitate the activation of the HO2S at engine startup (when the exhaust gas

temperature is low).

• The wide-range air/fuel ratio sensor converts the oxygen concentration in the exhaust gas into a current value,

and sends the value to the PCM.

• The PCM calculates the λ (lambda) value of the

air-fuel mixture based on the received current
value.

• (λ (lambda)) = (actual air/fuel ratio)/14.7

Rear HO2S

• A heater is built into the sensor to facilitate the activation of the HO2S at engine startup (when the exhaust gas

temperature is low).

• A zirconium element is used on the sensor. When there is a difference between the oxygen concentration

inside and outside the element, electromotive force is generated by the movement of oxygen ions (inside of the
zirconium element: atmosphere, outside: exhaust gas). The electromotive force changes significantly at the
boundary of the stoichiometric air/fuel ratio (A/F=14.7). The PCM receives the voltage generated from the
HO2S directly, and increases or decreases the fuel injection amount by the fuel injection control so that it is
close to the stoichiometric air/fuel ratio.

• When the temperature of the zirconium element is

low, electromotive force is not generated.
Therefore the HO2S is heated by a built-in heater,
facilitating the oxygen sensor activation. Due to
this, the sensor is efficiently activated even
immediately after cold-engine startup, and a
stable sensor output can be obtained.

End Of Sie

FTONT HO2S

REAR HO2S

E5U140ZW5307

0.7

0.9

0.8

1

1.1

1.2

1.3

1.4

-1.5

-1

-0.5

0

0.5

1

(

λ)

CURRENT(mA)

E5U140ZN5851

14.7

LOW

HIGH

OUTPUT
VOLTAGE

RICH

LEAN

AIR/FUEL

RATIO

CHU0140S075