Mass Air Flow (Maf) Sensor Function [Lf]; Mass Air Flow (Maf) Sensor Construction/Operation [Lf]; Heated Oxygen Sensor (Ho2S) Function [Lf] - Mazda 2006 MX-5 Service Highlights

MASS AIR FLOW (MAF) SENSOR FUNCTION [LF]

• Detects the air amount (mass airflow amount) inducted into the engine.
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MASS AIR FLOW (MAF) SENSOR CONSTRUCTION/OPERATION [LF]

• 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.
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HEATED OXYGEN SENSOR (HO2S) FUNCTION [LF]

• 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.
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CONTROL SYSTEM
COMPARISON
CIRCUIT
LARGE
VOLTAGE
SMALL
MAF SENSOR
HOT
COLD
WIRE
WIRE
FIXED
RESISTANCE
MAF SENSOR
VOLTAGE
CHARACTERISTIC
MASS AIR
LOW
FLOW AMOUNT
E5U014013215N01
E5U014013215N02
01–40
PCM
CPU
HIGH
E5U140ZN5852
E5U014018860N01
01–40–47