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:

Rear Turn Light Bulb Removal/Installation
1. Disconnect the negative battery cable.. 2. Insert a tape-wrapped flathead screwdriver into the service hole in the position shown in the figure. 3. Move the flathead screwdriver in the direction of the arrow (1) shown in the figure, pull out the service hole cover, and detach the serv ...

Ignition Switch
Push Button Start Positions The system operates only when the driver is in the vehicle or within operational range while the key is being carried. Each time the push button start is pressed, the ignition switches in the order of off, ACC, and ON. Pressing the push button start again from ON sw ...

Tire Pressure Monitoring System (TPMS)
Purpose, Outline The tire pressure monitoring system monitors the tire pressure of all 4 tires. If the tire pressure of 1 tire or more becomes excessively low, the driver is notified. A tire pressure monitoring system has been adopted which indirectly inspects the tire pres ...