Mazda X-5. Manual - part 43

 

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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.

End Of Sie

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.

End Of Sie

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

 

 

 

 

 

 

 

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