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:

Charcoal Canister Inspection
U.S.A. And CANADA Leakage inspection 1. Perform the following procedures: Do not operate CV solenoid valve. Assemble the hose used for inspection to port A. Cover ports B and C with the caps. CAUTION: Do not apply a pressure 20 kPa {150 mmHg, 5.91 inHg} o ...

Operational Range
The system operates only when the driver is in the vehicle or within operational range while the key is being carried. NOTE When the battery power is low, or in places where there are high-intensity radio waves or noise, the operational range may become narrower or the system may not operate ...

Torque Converter Clutch (TCC) Control Solenoid [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The torque converter clutch (TCC) control solenoid adjusts the hydraulic pressure in the TCC control circuit based on the current demand from the TCM according to the vehicle conditions. Construction The TCC control solenoid is installed to the solenoid con ...