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:

Engine Oil Pressure Warning Light
Purpose The engine oil pressure warning light warns the driver that the engine oil level is insufficient. Function When the instrument cluster receives the engine oil pressure warning light request signal sent from the PCM via the CAN signal, it illuminates the engine oi ...

Oil Jet Valve
Purpose, Function The oil jet valve injects engine oil on the back of the piston to cool the piston. Construction The oil jet valve is installed into the cylinder block. The oil jet valve is built into the check ball and spring. Operation 1. When ...

High Pressure Fuel Pump
Purpose, Function Applies pressure to fuel sent from the fuel pump equipped on the fuel tank, and then pumps it to the fuel delivery pipe. Fuel is sectioned and pumped by the up and down movement of the piston caused by the rotation of the cam installed to the rear end of the ex ...