Heated Oxygen Sensor (Ho2S) Heater Control Outline [Lf]; Heated Oxygen Sensor (Ho2S) Heater Control Block Diagram [Lf]; Operation Conditions - Mazda 2006 MX-5 Service Highlights

HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OUTLINE [LF]

• Stabilized oxygen concentrations, even when the exhaust gas temperature is low, are detected by controlling of
the HO2S, enabling feedback control of the fuel injection control even during cold-engine starting, improving
emission performance when cold.
• When the exhaust gas temperature is high, the HO2S is protected from sharp rises in its temperature by
stopping energization to the HO2S heater.
• Emission performance improvement and protection of the HO2S have both been achieved by the duty control
of the front and rear HO2S according to the engine operation conditions (exhaust gas temperature).
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HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL BLOCK DIAGRAM [LF]

ECT SENSOR
IAT SENSOR
CKP SENSOR
TP SENSOR NO.1, NO.2
MAF SENSOR
MAP SENSOR
BARO SENSOR
BATTERY
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HEATED OXYGEN SENSOR (HO2S) HEATER CONTROL OPERATION [LF]

Operation Conditions

• The PCM operates the HO2S when the following conditions are met.
HO2S
• After engine start
• After the engine has started and a fixed period
of time has elapsed (the elapsed time period
after the engine starts is determined by ECT).
• ECT is –10 °C {14 °F} or more.
Front
• Battery positive voltage is 9 V or more and less
than 16 V.
• MAF sensor is normal (no DTC is stored in
PCM).
• Starter is off
• After engine start
• After the engine has started and a fixed period
of time has elapsed (the time period after the
engine starts lengthen if the ECT falls below
Rear 0°C {32°F}.
• ECT is –10 °C {14 °F} or more.
• Battery positive voltage is 9 V or more and less
than 16 V.
• Charging efficiency is the fixed value or less, or
during fuel cut.
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01–40–32
CONTROL SYSTEM
PCM
Activation condition
FRONT HO2S HEATER
REAR HO2S HEATER
Drive signal
• The PCM outputs a duty signal.
• The element temperature is measured by the
impedance of the HO2S and a duty ratio is
determined.
• The PCM outputs a duty signal.
E5U014000000N40
E5U014000000N41
E5U140ZW5402
E5U014000000N42