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:

Roof Carrier Bracket Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the following parts: a. Sunroof seaming welt (with sunroof system). b. A-pillar trim. c. Front map light. d. Sunvisor. e. Front scuff plate. f. Rear scuff plate. g. B-pillar lower trim. h. Adjust anchor cover. i. Upper anchor i ...

Connecting Rod, Connecting Rod Bearing
Purpose, Function Connecting rod The connecting rod transmits the reciprocating movement of the piston to the crankshaft by engaging the piston pin and crank pin. Connecting rod bearing The connecting rod bearing forms an oil film on the outer surface of the crank pin to p ...

Precaution
Intermittent Concern Troubleshooting Vibration method If a malfunction occurs or becomes worse while driving on a rough road or when the engine is vibrating, perform the following steps. NOTE: There are several reasons why vehicle or engine vibration could cause an electr ...