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:

Accessory Sockets
Only use genuine Mazda accessories or the equivalent requiring no greater than 120 W (DC 12 V, 10 A). Front The ignition must be switched to ACC or ON. Center, Rear The accessory sockets can be used regardless of whether the ignition is on or off. CAUTION ●To prevent accessory ...

Lights On Reminder Warning Alarm
Purpose The lights-on reminder warning alarm notifies the driver that the TNS and headlights are not turned off. Function The instrument cluster receives the following vehicle condition signals via the CAN signal from the start stop unit and rear body control module (RBCM). ...

Rear Body Control Module (Rbcm) Inspection
1. Disconnect the negative battery cable.. 2. Remove the following parts: a. Trunk board. b. Trunk end trim. c. Rear scuff plate (LH). d. Trunk side trim (LH). 3. Remove the rear body control module (RBCM) from the body with the connector connected.. 4. Connect the negative battery c ...