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:

Service Publications
Service Publications Factory-authorized Mazda service publications are available for owners who wish to do some of their own maintenance and repair. When requesting any of our publications through an Authorized Mazda Dealer, refer to the chart below. If they do not have what you need in stock ...

Oil Control Valve (OCV) Inspection
Coil Resistance Inspection 1. Disconnect the negative battery cable.. 2. Remove the plug hole plate.. 3. Disconnect the OCV connector. 4. Measure the resistance between terminals A and B using an ohmmeter. OCV coil resistance 6.9—7.5 ohms [20°C {68°F}] If not as ...

Front Wheel Hub Bolt Replacement
1. Remove the brake calliper component from the steering knuckle and suspend it out of the way using a cable. 2. Remove the disc plate. 3. Remove the wheel hub bolt using the SST as shown in the figure. 4. Place a new wheel hub bolt in the wheel hub. 5. Install the wheel hub by placi ...