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:

Check Valve Inspection
Except U.S.A. And CANADA 1. Remove the check valve.. 2. Verify that there is no airflow when positive pressure is applied to port A. If there is airflow, replace the check valve.. 3. Verify that there is no airflow when negative pressure is applied to port A. If ther ...

Shift Lock System [Fw6 A EL, Fw6 Ax EL]
Purpose, Function The shift-lock system operates when the ignition is switched to ON and the brake pedal is not depressed, and inhibits the selector lever from being shifted from the P position to other positions. If the shift-lock cannot be released by the normal operation, it ...

Tie Rod Inspection
1. Inspect for bending and damage. If there is any malfunction, replace the tie rod. 2. Inspect for excessive play. If there is any malfunction, replace the tie rod. 3. Swing the tie rod five times. 4. Measure the swing torque of the tie rod using a pull scale. ...