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:

Air Bag System Service Warnings [Two Step Deployment Control System]
Air Bag Module Inspection Inspecting an air bag module using a tester can operate (deploy) the air bag module, which may cause serious injury. Do not use a tester to inspect an air bag module. Always use the on-board diagnostic function to diagnose the air bag module for malfunctions ...

Remote Transmitter Battery Voltage Inspection
NOTE: Because the remote transmitter battery power cannot be determined using the battery itself, determine by the remote transmitter battery low warning operation conditions. Operation procedure for remote transmitter battery low warning 1. Place the remote transmitter inside t ...

Camshaft Position (CMP) Sensor
Purpose/Function Detects the camshaft speed as basic information for mainly determining the fuel injection timing and ignition timing. Detects the camshaft speed and inputs it to the PCM as a CMP signal. Construction Intake CMP sensor Installed on the cylinder head. ...