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:

Audio Unit (With Color LCD)
NOTE: “iPod” is a registered trademark of Apple Inc. in the United States and other countries. Purpose The audio unit controls the CD, radio, exterior input devices (AUX/USB/iPod) and the display. Function Records the following items which the user has set ...

Switch Panel Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the car-navigation unit. (with car-navigation system). 3. Insert your hand from the lower side of the lower panel (without car-navigation system) or the area where the car-navigation unit was installed (with car-navigation system), press t ...

Manifold Absolute Pressure (Map) Sensor/Intake Air Temperature (Iat) Sensor No.2 Removal/Installation
NOTE: Because the IAT sensor No.2 is integrated in the MAP sensor, replacing the IAT sensor No.2 includes replacement of the MAP sensor/IAT sensor No.2. 1. Disconnect the negative battery cable.. 2. Disconnect the MAP sensor/IAT sensor No.2 connector. 3. Remove the MAP sensor/IA ...