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 ...

Drive Belt Removal/Installation
WARNING: A hot engine can cause severe burns. Turn off the engine and wait until it is cool before servicing. NOTE: Remove/install the drive belt from the underside of the vehicle. Generator Drive Belt Removal/Installation CAUTION: To prevent damage to the dri ...

Manual Transaxle Oil Replacement [C66 M R]
1. Park the vehicle on level ground. 2. Remove the front under cover No.2.. 3. Remove the drain plug and gasket, and drain the manual transaxle oil. 4. Install a new gasket and the drain plug. Tightening torque 39—59 N·m {4.0—6.0 kgf·m, 29—43 ft·lbf} 5. Remove the ...