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:

Differential Oil Temperature Sensor Inspection
WARNING: Hot differential oil may cause severe burns. Do not perform maintenance while differential oil is hot. 1. Disconnect the negative battery cable. 2. Disconnect the differential oil temperature sensor connector and remove the differential oil temperature sensor. 3. Wrap ...

Door Lock Switch Inspection
Driver's Side 1. Disconnect the negative battery cable.. 2. Remove the door lock switch.. 3. Verify that the continuity is as indicated in the table. If the continuity is not as indicated in the table, replace the door lock switch. Passenger's Side 1. Disconnec ...

Lap Pre Tensioner Seat Belt [Two Step Deployment Control System]
Purpose The lap pre-tensioner seat belts retract and tighten the seat belt webbing to protect the front passengers during a collision. Function The lap pre-tensioner seat belts operate (deploy) based on the operation signal from the SAS control module to instantly retract a ...