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:

Low Fuel Warning Light
Purpose The low fuel warning light warns the driver that the remaining fuel level is low. Function The instrument cluster calculates the fuel quantity based on the following CAN signals, and if a remaining fuel amount of approx. 10 L {2.6 US gal, 2.2 Imp gal} (fuel gauge ...

Front Parking Brake Cable Removal/Installation
1. Remove the front console box.. 2. Remove the shift lever knob. (MTX). 3. Remove the shift panel.. 4. Remove the upper panel.. 5. Remove the rear console.. 6. Remove in the order indicated in the table. 7. Install in the reverse order of removal. 8. After installation, inspect the pa ...

Front Door Latch Switch
Purpose, Function Switches on/off in conjunction with the latch lever rotation, and detects the front door open/closed condition by the voltage which is changed by the rear body control module (RBCM). Construction The switch is turned on/off by the rotation of the latch lev ...