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:

Front Fog Light Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the screws and bolt. 3. Pull up the front under cover No.1 and remove the mudguard screw shown in the figure. 4. Disconnect the connector. 5. While pressing the clip tab in the direction of the arrow (1) shown in the figure ...

Clock Spring Adjustment [Standard Deployment Control System]
1. Set the front wheels straight ahead. CAUTION: The clock spring will break if over?wound. Do not forcibly turn the clock spring. 2. Turn the clock spring clockwise until it stops. 3. Turn the clock spring counterclockwise approx. 2 turns. 4. Align the mark on the clo ...

Refrigerant Pressure Check
NOTE: Measure the refrigerant pressure after approx.10 min have elapsed from engine start. 1. Install the manifold gauge.. 2. Start the engine and warm it up. 3. Set the fan speed MAX HI. 4. Turn the A/C switch on. 5. Set to RECIRCULATE mode. 6. Set the temperature control ...