Mazda CX-5 Service & Repair Manual: Air Fuel Ratio (A/F) Sensor Heater Control

Mazda CX-5 Service & Repair Manual / Engine / Control / Air Fuel Ratio (A/F) Sensor Heater Control

Outline

Based on the control of the A/F sensor 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).
A pre-heater has been adopted to prevent water, produced from the exhaust system when the engine is started, from adhering to the sensor and damaging it.

Block Diagram

Operation

Pre-heater control

The A/F sensor heater is operated at a duty ratio of approx. 15% within the specified time directly after the engine is started.

Normal control

The PCM operates the A/F sensor based on the following control conditions:


Output duty ratio	Control condition
0%	Ignition switched off Engine stopped Engine start (cranking)
0?100% (Duty ratio determined by measuring the element temperature by the A/F sensor heater element impedance)	After engine warm-up (value fluctuates by battery condition, etc.)

Output duty ratio

Control condition

Ignition switched off
Engine stopped
Engine start (cranking)

0?100%

(Duty ratio determined by measuring the element temperature by the A/F sensor heater element impedance)

After engine warm-up (value fluctuates by battery condition, etc.)

Accelerator Pedal Position (App) Sensor

Purpose/Function Detects the accelerator pedal depression amount as basic information for mainly determining the throttle valve opening. Detects the accelerator pedal depression amou ...

Air Fuel Ratio (A/F) Sensor Inspection

A/F Sensor 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-M ...

Other materials:

Keys
WARNING Do not leave the key in your vehicle with children and keep them in a place where your children will not find or play with them: •eaving children in a vehicle with the key is dangerous. This could result in someone being badly injured or even killed. Children may find these keys to ...

Intake Air Temperature (Iat) Sensor
IAT Sensor No.1 Purpose/Function Detects the IAT before it passes through the throttle body as basic information for mainly determining the fuel injection amount. Detects the IAT before it passes through the throttle body and inputs it to the PCM as an IAT signal. Constru ...

Condenser Removal/Installation
1. Disconnect the negative battery cable.. 2. Discharge the refrigerant.. 3. Remove the front under cover No.1.. 4. Drain the engine coolant.. 5. Remove the following parts: a. Plug hole plate. b. Air cleaner, air hose and fresh air duct component. c. Coolant reserve tank. d. Cooling ...