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:

Mirror Base Removal
1. Disconnect the negative battery cable.. 2. Remove the rearview mirror. (without auto-dimming mirror). 3. Remove the auto-dimming mirror. (with auto-dimming mirror). 4. Wind each end of a wire around a bar. WARNING: Using the piano wire with bare hands can cause injury. Always ...

Front Center Speaker Inspection
1. Disconnect the negative battery cable.. 2. Remove the center speaker grille.. 3. Remove the front center speaker.. 4. Verify that the resistance between the front center speaker terminals is as indicated in the table. If not as indicated in the table, replace the front center ...

Passenger Compartment Temperature Sensor Inspection [Full Auto Air Conditioner]
1. Measure the temperature around the passenger compartment temperature sensor and measure the resistance between passenger compartment temperature sensor terminals A and B. If the characteristics of the passenger compartment temperature sensor are not as shown in the graph, replace t ...