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 Shock Absorber Disposal
WARNING: Whenever drilling into a front shock absorber, wear protective eye wear. The gas in the front shock absorber is pressurized, and could spray metal chips into the eyes and face when drilling. 1. Place the shock absorber on a level surface or with the piston pointing d ...

Cooling Fan Relay
Purpose, Function The cooling fan relay operates by receiving the signal from the PCM to supply power to the cooling fan motor. Construction The cooling fan relay is installed on the relay and fuse block. Operation The contact point is on when the battery vo ...

Blind Spot Monitoring (Bsm) Off Switch
Purpose The blind spot monitoring (BSM) system can be turned on or off optionally by the driver. Function The switch operation signal is sent to the instrument cluster. Construction The BSM OFF switch is built into the cluster switch. The resistance is bui ...