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:

Rear ABS Wheel Speed Sensor Inspection [Awd]
Installation Visual Inspection 1. Inspect the following items: If there is any malfunction, replace the applicable part. a. Excessive play of the ABS wheel-speed sensor b. Deformation of the ABS wheel-speed sensor c. Deformation or damage of the ABS sensor rotor Clearance Inspec ...

Brake Fluid Pressure Sensor Inspection
1. Switch the ignition to off. 2. Remove the clips. 3. Set the splash shield out of the way. 4. Disconnect the brake pipe from the LF brake hose. 5. Remove the clip. 6. Remove the LF brake hose from the bracket. 7. Detach the brake pipe from the pipe holder. 8. Install the SST ...

Engine Mount
Purpose, Function The engine mount secures the engine and transaxle to the vehicle body, reducing vibration and noise. Construction The three points at the engine front (No.3 engine mount), one side of the transaxle (No.1 engine mount), and the rear upper part of the transa ...