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 Accessory Socket Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the front console.. 3. Insert a tape-wrapped flathead screwdriver into the gap between the cap tab and socket. 4. Move the flathead screwdriver in the direction of the arrow (1) shown in the figure, press the front accessory socket i ...

Throttle Body
Purpose, Function Opens/closes the throttle valve to adjust the amount of air supplied to the cylinder. Opens/closes the throttle valve according to the control signal from the PCM. Construction The throttle body is installed to the intake manifold. Th ...

On/Off Solenoid [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The on/off solenoid performs switching of the shift valve in the control valve body according to the vehicle conditions. Construction The on/off solenoid is installed to the solenoid control valve body. The on/off solenoid is a normal open-type on/off ...