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:

Brake Pedal Inspection
Pedal Height Inspection 1. Measure the distance from the center of the upper surface of the pedal pad to the insulator and verify that it is as specified. If not within the specification, inspect the following items and repair or replace the applicable part if there is any malfunct ...

On Board Diagnostic System PID/Data Monitor Inspection [Fw6 A EL, Fw6 Ax EL]
1. Connect the M-MDS to the DLC-2. 2. After the vehicle is identified, select the following items from the initialization screen of the M-MDS. a. Select “DataLogger”. b. Select “Modules”. c. Select “TCM”. 3. Select the applicable PID from the PID table. 4. Verify the PID da ...

Turbine/Input Shaft Speed Sensor, Output Shaft Speed Sensor [Fw6 A EL, Fw6 Ax EL]
Purpose/Function The turbine/input shaft speed sensor detects the rotation speed of the input shaft (low clutch drum). The output shaft speed sensor detects the rotation speed of the output shaft (primary gear). The turbine/input shaft speed sensor and output shaft speed ...