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:

Clock Input/Output Check Mode
Activation procedure Inspection NOTE: The clock input/output check mode is displayed in the following order and returning to the previous screen is impossible. If you want to check All LCD illuminated or Check code 1 or 2 after Check code 6 is displayed, activate the inpu ...

Multiplex Communication System
A controller area network (CAN) system has been adopted in which multiplex communication is performed using a single communication path. A high-speed controller area network (HS-CAN) has been adopted for the communication between the following modules: PCM ...

Cooling Fan Motor Inspection
Part Inspection 1. Verify that the battery is fully charged.. 2. Disconnect the cooling fan motor connector (2 terminals). 3. Install a tester and battery to the cooling fan motor connector (2 terminals) as shown in the figure. 4. Verify that each cooling fan motors operate smoothly at ...