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:

Brake Fluid Level Sensor Inspection
1. Disconnect the brake fluid level sensor connector from the master cylinder. 2. Inspect for continuity according to fluid level between the brake fluid level sensor terminals. If not as indicated in the table, replace the reserve tank.. ...

Car Navigation System
Outline The car-navigation system displays point-of-origin and road guidance maps via the audio unit display and provides guidance and information to the desired point of destination. NOTE: For the car-navigation system operation, refer to the owner's manual. ...

Positive Crankcase Ventilation (PCV) Valve
Purpose, Function Prevents release of blow-by gas (unburnt gas) into the atmosphere. The PCV valve is open/closed by the intake manifold vacuum. Construction The PCV valve is installed to the oil separator. The PCV valve consists of a spring and valve. ...