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:

Hazard Warning Switch Inspection
1. Disconnect the negative battery cable.. 2. Remove the decoration panel.. 3. Verify that the continuity between the hazard warning switch terminals is as indicated in the table. If the continuity is as indicated in the table, go to the next step. If not as indicated i ...

Auto Light Sensor
Purpose The auto light sensor detects the illumination level above and in front of the vehicle and outputs it to the front body control module (FBCM). Function The auto-light sensor uses the upward illumination level sensor to detect the illumination level above the vehicle ...

Engine Oil Solenoid Valve
Purpose, Function The engine oil solenoid valve switches the hydraulic transmission passage in accordance with the driving conditions and the oil pump drive resistance is reduced by controlling oil pump discharging pressure in two steps. Construction The engine oil solenoid ...