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:

Intake Air Temperature (Iat) Sensor Inspection
IAT Sensor No.1 Resistance inspection NOTE: Because the IAT sensor No.1 is integrated in the MAF sensor, replacing the IAT sensor No.1 includes replacement of the MAF sensor/IAT sensor No.1. 1. Disconnect the negative battery cable.. 2. Disconnect the MAF sensor/IAT sensor No.1 ...

Rear Differential Removal/Installation
WARNING: When replacing the coupling component, read the special character string before installing a new coupling component and write it to the AWD control module after replacement. The special character string is indicated in the two locations shown in the figure. 1. D ...

Hood
WARNING Always check that the hood is closed and securely locked: A hood that is not closed and securely locked is dangerous as it could fly open while the vehicle is moving and block the driver's vision which could result in a serious accident. Opening the Hood 1. With the vehicle parke ...