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:

Propeller Shaft Removal/Installation
CAUTION: If the constant velocity joint is bent during propeller shaft removal/installation or transportation after servicing, the constant velocity joint boot may contact the metallic cover and the boot may be damaged. Insert a rag between the boot and the metallic cover before ser ...

Front Sash Molding Installation
WARNING: Using a utility knife with bare hands can cause injury. Always wear gloves when using a utility knife. NOTE: Double-sided adhesive tape has already been attached to the new front sash molding. 1. When installing a new front sash molding, follow the procedur ...

Accessory Sockets
Only use genuine Mazda accessories or the equivalent requiring no greater than 120 W (DC 12 V, 10 A). Front The ignition must be switched to ACC or ON. Center, Rear The accessory sockets can be used regardless of whether the ignition is on or off. CAUTION ●To prevent accessory ...