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:

Front Door Key Cylinder Removal/Installation
1. Disconnect the negative battery cable.. 2. Remove the service hole cover. 3. Detach the screw from the front door key cylinder. NOTE: The screw cannot be removed because the front outer handle bracket has a stopper which prevents the screw from falling. 4. While pre ...

High Pressure Fuel Pump
Purpose, Function Applies pressure to fuel sent from the fuel pump equipped on the fuel tank, and then pumps it to the fuel delivery pipe. Fuel is sectioned and pumped by the up and down movement of the piston caused by the rotation of the cam installed to the rear end of the ex ...

Liftgate Opener System
Outline A liftgate opener system has been adopted in which the liftgate can be opened just by pressing the liftgate opener switch. The rear body control module (RBCM) performs liftgate opener system fail-safe.. Function When the liftgate opener switch is pressed, the l ...