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:

Vacuum Pump Removal/Installation
1. Remove the plug hole plate.. 2. Remove the battery.. 3. Set the PCM wiring harness out of the way. 4. Disconnect the vacuum hose from the vacuum pump.. 5. Remove in the order shown in the table. 6. Install in the reverse order of removal. 1 Vacuum hose ...

Seat Belt Inspection
Belt 1. Verify that the belt is installed properly with no twists or kinks. 2. Verify that there is no damage to the seat belt and no deformation of the metal fittings. If there is any malfunction, replace the seat belt. ELR (Emergency Locking Retractor) Except rear center seat b ...

Scheduled Maintenance (Mexico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following conditions apply. • Repeated short-distance driving • Driving in dusty conditions • Driving with extended use of brakes • Driving in areas where salt or other corrosive materials are used • Driving on ...