Mazda CX-5 Service & Repair Manual: Air Fuel Ratio (A/F) Sensor Heater Control
Outline
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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.
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Both emission performance and sensor protection have been improved by duty control of the heater according to engine operation conditions (exhaust gas temperature).
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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
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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
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The PCM operates the A/F sensor based on the following control conditions:
|
Output duty ratio |
Control condition |
|
0% |
|
|
0?100% (Duty ratio determined by measuring the element temperature by the A/F sensor heater element impedance) |
|
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:
Camshaft Position (CMP) Sensor Removal/Installation
CAUTION:
When replacing the CMP sensor, make sure there is no foreign material on
it such as metal shavings. If it is installed with foreign material, the sensor
output signal will malfunction resulting from fluctuation in magnetic flux and
cause a deterioration in engine control.
...
Vanity Mirror Illumination Inspection
1. Disconnect the negative battery cable..
2. Remove the sunvisor..
3. Verify that the continuity between the vanity mirror illumination terminals
is as indicated in the table.
If not as indicated in the table, replace the sunvisor.
...
Start Stop Unit Inspection
1. Remove the following parts:
a. Column cover.
2. Verify that the voltages of each of the terminals are as indicated in the
terminal voltage table (reference).
If the voltage is not as specified in the terminal voltage table (reference),
inspect the parts under Inspection item(s) a ...
