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:

High Clutch [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The high clutch operates in 4GR, 5GR, and 6GR and intermittently operates the rear carrier by drive force from the turbine shaft. For the high clutch, a centrifugal balance clutch has been adopted to prevent clutch drag and to assure stabilized piston thrust in ...

Changing a Flat Tire
NOTE If the following occurs while driving, it could indicate a flat tire. • Steering becomes difficult. • The vehicle begins to vibrate excessively. • The vehicle pulls in one direction. If you have a flat tire, drive slowly to a level spot that is well off the road and out of the way ...

Oil Pressure Switch [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The oil pressure switch detects the engagement pressures of the low clutch, 2-6 brake, R-3-5 brake, and the high clutch. The oil pressure switch signal is used for automatic shift control, manual shift control, TCC control, line pressure control, direct electric ...