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:

Blower Unit Disassembly/Assembly
CAUTION: Apply only the specified grease to the link. Otherwise abnormal noise or improper operation may result. 1. Disassemble in the order indicated in the table. 1 Air filter 2 Harness 3 Blower ...

Start Stop Unit Inspection
1. Remove the following parts: a. Column cover. 2. Verify that the voltages of each of the terminals are as indicated in the terminal voltage table (reference). If the voltage is not as specified in the terminal voltage table (reference), inspect the parts under Inspection item(s) a ...

Keyless Antenna Removal/Installation
With Advanced Keyless Entry System Vehicle interior, front 1. Disconnect the negative battery cable.. 2. Remove the following parts: a. Decoration panel. b. Shift lever knob (MTX). c. Front console box. d. Shift panel. e. Upper panel. f. Rear console. g. Side wall. h. Front conso ...