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:

Mass Air Flow (MAF) Sensor Inspection
Visual Inspection 1. Remove the MAF sensor/IAT sensor No.1.. 2. Visually inspect the MAF sensor for the following: Damage, cracks, soiling Rusted sensor terminal Bent sensor terminal If there is any malfunction, repair or replace the MAF sensor/IAT sensor ...

Oil Pan
Purpose, Function The engine oil required for lubrication in the engine accumulates in the oil pan. Construction The oil pan is installed on the lower part of the cylinder block. Silicone sealant with excellent sealing has been adopted for the oil pan gask ...

Auto Dimming Mirror Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the screw B. 3. Remove the auto-dimming mirror in the direction of arrow (1) shown in the figure. 4. Detach tabs while push the cover No.2 in the direction of the arrow (2) shown in the figure, then remove the cover No.2 in the d ...