Mazda CX-5 Service & Repair Manual: Heated Oxygen Sensor (HO2 S) Heater Control

Mazda CX-5 Service & Repair Manual / Engine / Control / Heated Oxygen Sensor (HO2 S) Heater Control

Outline

Based on the control of the HO2S heater, a stabilized oxygen concentration is detected even at low exhaust temperatures, and feedback control of fuel injection even at cold engine start is made possible for improved cold temperature exhaust emission performance.
Both emission performance and sensor protection have been improved by duty control of the heater according to engine operation conditions (exhaust gas temperature)

Block Diagram

Operation

The PCM operates the HO2S heater based on the following control conditions.


Output duty ratio	Control condition
0%	Engine stopped Fuel cut injection control is in engine start zone Engine coolant temperature is -10 °C {14 °F}or less Other than battery voltage of 10—16 V Within a fixed period of time after engine start (varies according to engine coolant temperature)
30%	HO2S not activated
0?100% (Determined by engine speed and charging efficiency)	Other than the above

Engine Coolant Temperature (ECT) Sensor

Purpose/Function Detects the ECT as basic information for mainly determining the fuel injection amount. Detects the ECT and inputs it to the PCM as an ECT signal. The ECT sen ...

Heated Oxygen Sensor (HO2 S) Inspection

HO2S Inspection 1. Connect the M-MDS to the DLC?2. 2. Switch the ignition ON (engine on). 3. Warm up the engine to normal operating temperature. 4. Access the following PIDs using the M-MDS.. ...

Other materials:

Evaporator
Purpose The evaporator cools the passing air. Function The evaporator vaporizes the atomized refrigerant flowing internally, and the air passing through the evaporator is cooled by the release of latent heat. The moisture in the air is condensed at this time and dehumidifie ...

Cylinder Head Gasket
Purpose, Function The cylinder head gasket is installed between the cylinder head and cylinder block to prevent leakage of air-fuel mixture, combustion gas, engine oil, and engine coolant. Construction A four-layer type metal gasket has been adopted for the cylinder head ga ...

Rear Combination Light
Purpose The rear combination lights are used to signal the following conditions to vehicles/people at the rear. Rear turn lights: Signals a left or right turn of the vehicle. Brake lights: Signals a vehicle stop. Taillights: Signals the presence of the ve ...