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:

Windshield Wiper Arm And Blade Adjustment
1. Switch the ignition ON (engine off or on). 2. Operate the windshield wiper at low speed. 3. Verify that the windshield wiper operates at low speed and stop the windshield wiper. 4. Verify that the windshield wiper stops at the auto-stop position. 5. Remove the windshield wiper arm and b ...

Side Member Removal [Panel Replacement]
Symbol Mark Removal Procedure 1. Drill the 45 locations shown in the figure. NOTE: When drilling, do not drill a hole all the way through or there could be a problem when installing the new part. 2. Remove the side member. ...

Clutch Fluid Inspection [C66 M R]
NOTE: A common reserve tank is used for the clutch system and brake system. 1. Verify that the clutch fluid is between the MIN mark and the MAX mark. Verify that there is no clutch fluid leakage then add clutch fluid to the level between the MIN mark and the MAX mark.. ...