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:

Front Door Speaker Inspection
1. Disconnect the negative battery cable.. 2. Remove the following parts: a. Inner garnish. b. Front door trim. 3. Disconnect the front door speaker connector.. 4. Verify that the resistance and continuity between the front door speaker terminals is as indicated in the table. ...

Speaker Grille Removal/Installation
Center Speaker Grille 1. Insert a tape-wrapped flathead screwdriver into shown in the figure and remove hooks A in the direction of arrow (1). 2. Take the shaded area shown in the figure, and remove the center speaker grille in the direction of arrow (2) while detaching hooks B. 3. ...

TCM [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The TCM detects the vehicle conditions and performs calculations and processing based on input information from each type of sensor and switch. Outputs control signals to each solenoid valve so that each type of control is optimally implemented according to the ...