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:

Engine Coolant Temperature (ECT) Sensor Removal/Installation
WARNING: When the engine is hot, it can badly burn. Turn off the engine and wait until it is cool before removing the ECT sensor. ECT Sensor No.1 1. Disconnect the negative battery cable.. 2. Remove the plug hole plate.. 3. Drain the engine coolant.. 4. Pull out the evaporati ...

Fog Lights
Use this switch to turn on the fog lights. The fog lights will improve visibility at night and during foggy conditions. To turn the fog lights on, rotate the fog light switch to the position. The headlight switch must be in the position before turning on the fog lights. To turn the fog lig ...

Antenna Feeder No.2 Inspection
1. Disconnect the negative battery cable.. 2. Remove the following parts: a. A-pillar trim (RH). b. Trunk board. c. Trunk end trim (RH). d. Rear scuff plate (RH). e. Trunk side trim (RH). 3. Disconnect antenna feeder No.1. 4. Disconnect antenna feeder No.3. 5. Verify that t ...