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:

Refrigerant Pressure Sensor [Full Auto Air Conditioner]
Purpose The refrigerant pressure sensor detects the refrigerant pressure in the refrigerant cycle. Function The refrigerant pressure sensor converts the detected refrigerant pressure to an electric signal and sends it to the PCM. Construction The refriger ...

Electric Power Steering (Eps) Motor
Purpose, Function The EPS motor is driven by the control current from the EPS CM (control module) and generates assist torque to manual steering mechanism. Construction The EPS motor is installed to the steering column with an integrated EPS CM. The EPS motor is a b ...

Oil Strainer
Purpose, Function The oil strainer suctions the engine oil in the oil pan using the oil pump vacuum. The engine oil is filtered by the internal filter at that time. Construction The oil strainer is installed on the suction port of the oil pump. The oil strain ...