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 Glass Removal/Installation
1. Perform the front door glass preparation.. NOTE: Before removing the front door glass, the removal procedure for the front door glass installation bolt can be facilitated by adjusting the top of the front door glass to the position approx. 90 mm {3.5 in} away from the upper par ...

Interior Equipment (View A)
1 Door-lock knob 2 TCS OFF switch 3 Tire pressure monitoring system set switch 4 Turn and lane-change signal 5 Lighting control 6 Instrument cluster 7 Dashboard illumination knob 8 Wiper and washer lever 9 Push button start 10 AFS OFF switch 11 BSM OFF switch 12 Outside mirror ...

Rear Mount Camera Inspection
1. Disconnect the negative battery cable.. 2. Remove the following parts: a. Liftgate upper trim. b. Liftgate side trim. c. Liftgate lower trim. d. Liftgate garnish. e. Rear mount camera. 3. Prepare four dry cell batteries (1.5 V) 4. Connect the four dry cell batteries in a series. ...