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:

Steering Angle Sensor Inspection
1. Remove the column cover.. 2. Connect the plus (+) end of a tester to steering angle sensor terminal A and the minus (-) end of the tester to terminal B (GND). 3. Switch the ignition ON (engine off or on). 4. Turn the steering wheel to the left and right. 5. Verify that the voltage f ...

Engine Oil
NOTE Changing the engine oil should be performed by an Authorized Mazda Dealer. Refer to Introduction for owner's responsibility in protecting your investment. Recommended Oil U.S.A. and CANADA 0W-20 full synthetic recommended: Mazda Genuine Oil is used in your Mazda vehicle and is t ...

Mass Air Flow (MAF) Sensor/Intake Air Temperature (Iat) Sensor No.1 Removal/Installation
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 connector. 3. Remove the MAF sensor/IA ...