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:

Low Clutch [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The low clutch operates in 1GR, 2GR, 3GR and 4GR and intermittently operates the sun gear by drive force from the turbine shaft. For the low clutch, a centrifugal balance clutch has been adopted to prevent clutch drag and to assure stabilized piston thrust in al ...

Charcoal Canister
Purpose, Function Absorbs evaporative gas flowing from the fuel tank to prevent release of the gas into the atmosphere. Construction The charcoal canister is installed near the fuel tank. U.S.A. and CANADA Except U.S.A. and CANADA The charcoal canister ...

Map Light Bulb Removal/Installation
Front Map Light 1. Disconnect the negative battery cable.. 2. To prevent scratches or damage, affix protective tape to the position shown in the figure. CAUTION: If a flathead screwdriver is inserted into the gap between the front map light and lens, the front map light could inter ...