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:

Starting the Engine
WARNING Radio waves from the key may affect medical devices such as pacemakers: Before using the key near people who use medical devices, ask the medical device manufacturer or your physician if radio waves from the key will affect the device. NOTE • The key must be carried because the ke ...

Accelerator Pedal Position (App) Sensor Inspection
Voltage Inspection NOTE: Because the APP sensor is integrated in the accelerator pedal, replacing the APP sensor includes replacement of the accelerator pedal. 1. Connect the M-MDS to the DLC?2. 2. Switch the ignition ON (engine off or on). 3. Verify that the APP sensor output ...

Coil Antenna
Purpose Sends the ID data programmed to the electronic transmission device (transponder) in the remote transmitter to the start stop unit. Function A magnetic field occurs around the push button start. Construction, Operation The coil antenna built into the push b ...