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:

Coolant Reserve Tank Removal/Installation
1. Remove in the order indicated in the table. 2. Install in the reverse order of removal. 1 Wiring harness 2 Hose 3 Coolant reserve tank (See Coolant Reserve Tank Removal Note.) Coolant Reserve Ta ...

Parking Brake Lever Inspection
Stroke Inspection 1. Pump the brake pedal a few times. 2. Pull the parking brake lever two to three times. 3. Inspect the parking brake stroke by slowly pulling at point A 50 mm {2.0 in} from the end of the parking brake lever with a force of 98 N {10 kgf, 22 lbf} and counting the number of ...

Front Seat Side Cover Removal/Installation
WARNING: Handling a side air bag improperly can accidentally operate (deploy) the air bag, which may seriously injure you. Read the service warnings in the Workshop Manual before handling the front seat (side air bag integrated).. If the sliding mechanisms on both sides are ...