Mazda CX-5 Service & Repair Manual: Heated Oxygen Sensor (HO2 S) Heater Control
Outline
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Based on the control of the HO2S 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)
Block Diagram
Operation
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The PCM operates the HO2S heater based on the following control conditions.
|
Output duty ratio |
Control condition |
|
0% |
|
|
30% |
|
|
0?100% (Determined by engine speed and charging efficiency) |
|
Engine Coolant Temperature (ECT) Sensor
Purpose/Function
Detects the ECT as basic information for mainly determining the fuel injection
amount.
Detects the ECT and inputs it to the PCM as an ECT signal.
The ECT sen ...
Heated Oxygen Sensor (HO2 S) Inspection
HO2S 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-MDS..
...
Other materials:
Differential Oil Temperature Sensor Removal/Installation
WARNING:
Hot differential oil may cause severe burns. Do not perform maintenance while
differential oil is hot.
1. Disconnect the negative battery cable.
2. Disconnect the differential oil temperature sensor connector.
3. Remove the differential oil temperature sensor.
4. ...
Throttle Body Inspection
Resistance Inspection
1. Disconnect the negative battery cable..
2. Disconnect the throttle body connector.
3. Measure the resistance between throttle body terminals E and F.
Throttle body resistance
1.38 ohms [20°C {68 °F}]
If not as specified, replace the throttle ...
Abbreviations
AAS
Active Adaptive Shift
ABS
Antilock Brake System
ABDC
After Bottom Dead Center
ACC
Accessories
AFS
Adaptive Front Lighting System
ALC
...
