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:

Propeller Shaft Inspection
1. Measure the propeller shaft center runout using the dial gauge. If it exceeds the maximum specification, replace the propeller shaft as a single component. Propeller shaft maximum runout 0.8 mm {0.031 in} 2. Inspect the play and rotation of the joint by turning ...

Sail Garnish Removal/Installation
1. Open the front door. 2. Affix protective tape to the position shown in the figure. 3. Insert a tape-wrapped flathead screwdriver into the shown in the figure and remove the clip A in the direction of arrow (1). 4. Pull the sail garnish in the direction of the arrow (2) and remove it w ...

Front ABS Wheel Speed Sensor Removal/Installation
1. Remove the mudguard.. 2. Remove in the order indicated in the table. 3. Install in the reverse order of removal. 4. After installation, verify that there is no twisting in the front ABS wheel-speed sensor. 1 Connector 2 Bolt ...