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:

Shift Solenoid No.1 [Fw6 A EL, Fw6 Ax EL]
Purpose/Function Shift solenoid No.1 adjusts the hydraulic pressure in the low clutch circuit based on the current demand from the TCM according to the vehicle conditions. Construction Shift solenoid No.1 is installed to the solenoid control valve body. Shift solenoid ...

Resistor Inspection [Manual Air Conditioner]
1. Verify that the resistance between the resistor terminals is as shown in the table. If there is any malfunction, replace the resistor. Terminal Resistance (ohm) A—D 0.35—0.41 A—B 0. ...

Air Intake Actuator [Full Auto Air Conditioner]
Purpose The air intake actuator moves the air intake door in the blower unit to switch the air intake port. Function The air intake actuator drives the motor based on the signal from the climate control unit and moves the air intake door to the FRESH or REC position. ...