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:

Keyless Entry System
This system uses the key buttons to remotely lock and unlock the doors and the liftgate. The system can start the engine without having to take the key out of your purse or pocket. It can also help you signal for attention. Operating the theft-deterrent system is also possible on theft-deterr ...

Cowl Upper Plate Removal [Panel Replacement]
Symbol Mark Removal Procedure 1. Drill the 9 locations indicated by (A) shown in the figure. 2. Drill the 2 locations by (B) from the front wheel housing side shown in the figure. 3. Drill the 2 locations indicated by (C) from the inside shown in the figure. 4. Remove the cowl upp ...

Front Sash Molding Installation
WARNING: Using a utility knife with bare hands can cause injury. Always wear gloves when using a utility knife. NOTE: Double-sided adhesive tape has already been attached to the new front sash molding. 1. When installing a new front sash molding, follow the procedur ...