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:

Brake Switch Inspection
CAUTION: Inspect the brake switch with it installed to the brake pedal, otherwise the brake switch may not operate normally. If the brake switch is removed from the brake pedal, replace the brake switch with a new one. 1. Remove the lower panel.. 2. Remove the front heat duct ( ...

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 ...

Transfer Oil Seal Replacement [Fw6 Ax EL]
Transfer oil seal (LH) 1. Drain the transfer oil.. 2. Remove the transfer from the vehicle.. 3. Insert a tape-wrapped flathead screwdriver into the lip area of the oil seal (LH) as shown in the figure and remove the oil seal (LH). 4. Using the SST and a hammer, tap the new seal into pla ...