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:

Replace Electrical Battery
If the buttons on the transmitter are inoperable and the operation indicator light does not flash, the battery may be dead. Replace with a new battery before the transmitter becomes unusable. CAUTION ● Make sure the battery is installed correctly. Battery leakage could occur if it is no ...

Engine Oil
NOTE Changing the engine oil should be performed by an Authorized Mazda Dealer. Refer to Introduction for owner's responsibility in protecting your investment. Recommended Oil U.S.A. and CANADA 0W-20 full synthetic recommended: Mazda Genuine Oil is used in your Mazda vehicle and is t ...

Fuel Injector Inspection
Resistance Inspection 1. Disconnect the negative battery cable.. 2. Remove the plug hole plate.. 3. Disconnect the fuel injector connector. 4. Inspect the resistance between fuel injector terminals A and B. Fuel injector resistance 1.74—2.04 ohms [20 °C {68 °F}] ...