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:

Washer Motor Inspection
1. Disconnect the negative battery cable.. 2. Set the front over fender aside.. 3. Set the mudguard (RH) aside.. 4. Remove the front bumper.. 5. Disconnect the washer motor connector from the washer motor. 6. Disconnect the windshield washer hose from the washer motor. 7. Disconnect the ...

Awd Warning Light
Purpose, Function Warns the driver of a AWD system malfunction. Construction The AWD warning light is built into the instrument cluster. Operation If the self-diagnostic function stores a DTC, the warning light illuminates to alert the driver of the malfunct ...

Water Pump
Purpose, Function The water pump operates by obtaining drive force from the engine via the drive belt to pump engine coolant. Construction The water pump is installed to the engine front. The water pump consists of the following parts: A hard plasti ...