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:

Driveline/Axle Features
Improved driveability Bell-shaped constant velocity joint adopted for wheel-side joint of front and rear drive shaft Tripod-shaped constant velocity joint adopted for differential-side joint of front drive shaft (ATX) and rear drive shaft ...

PID/Data Monitor Inspection [Standard Deployment Control System]
1. Connect the M-MDS to the DLC?2. 2. After the vehicle is identified, select the following items from the initialization screen of the M-MDS. a. Select “DataLogger”. b. Select “Modules”. c. Select “RCM”. 3. Select the applicable PID from the PID table. 4. Verify the PID da ...

Afs Off Indicator Light
Purpose The AFS OFF indicator light notifies the user that the AFS is stopped or a malfunction occurs in the AFS. Function The AFS OFF indicator light illuminates when the AFS is stopped and flashes when a malfunction occurs in the AFS. Construction When the mi ...