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:

Oil Seal (Control Valve Body) Replacement [Fw6 A EL, Fw6 Ax EL]
1. Disconnect the negative battery cable.. 2. Remove the air cleaner component.. 3. Disconnect the control valve body connector. CAUTION: Make sure that your hand does not touch the terminal as the connector terminal could be damaged. Water or foreign objects entering th ...

Front Crossmember Removal/Installation
CAUTION: Performing the following procedures without first removing the front ABS wheel-speed sensor may possibly cause an open circuit in the wiring harness if it is pulled by mistake. Before performing the following procedures, disconnect the front ABS wheel-speed sensor wiring ha ...

Oil Seal (Differential) Replacement [C66 M R]
1. Remove the front under cover No.2.. 2. Drain the manual transaxle oil.. 3. Disconnect the drive shaft (LH) from the MTX.. 4. Disconnect the drive shaft (RH) from the MTX.. 5. Remove the oil seal (LH). 6. Remove the oil seal (RH). 7. Using the SSTs and a hammer, tap a new oil s ...