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:

Air Cleaner
Purpose, Function Prevents engine internal damage caused by penetration of dust or foreign material. Construction The air cleaner is installed in front of the battery. The air cleaner consists of the air cleaner case, air cleaner cover, and air cleaner element ...

Parking/Front Turn Light Bulb Removal/Installation
Halogen Type 1. Disconnect the negative battery cable.. 2. Rotate the socket in the direction of the arrow (1) shown in the figure and remove it from the front combination light in the direction of the arrow (2) shown in the figure. 3. Remove the parking/front turn light bulb. 4. ...

Power Window Subswitch Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the cover A. 3. Insert a tape-wrapped fastener remover shown in the figure and remove the tab B in the direction of arrow (1). 4. Slide the power window subswitch cover in the direction of the arrow (2) shown in the figure and re ...