Mazda 2: Heated Oxygen Sensor (HO2S)
HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION
WARNING:
- A hot engine and exhaust system can cause severe burns. Turn off the engine and wait until they are cool before removing the exhaust system.
1. Disconnect the negative battery cable.
2. Remove the air cleaner cover. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION).
3. Disconnect the HO2S connector.
4. Remove the HO2S using the SST.
5. Install in the reverse order of removal.
HEATED OXYGEN SENSOR (HO2S) INSPECTION
HO2S Inspection
1. Warm up the engine to normal operating temperature.
2. Using the M-MDS, monitor the following:
- Vehicle speed (PID: VSS)
- Engine speed (PID: RPM)
- HO2S voltage (PID: O2S12)
3. Drive the vehicle and decelerate the engine speed by releasing the accelerator pedal fully when the engine speed is 3,000 rpm or more.
4. Verify that the HO2S outputs a voltage of 0.6 V or more, one time or more, then verify that the HO2S voltage (PID: O2S12) is 0.3 V or less while decelerating as shown in the figure.
- If not as specified, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION).
HO2S Heater Inspection
1. Disconnect the HO2S connector.
2. Measure the HO2S resistance between terminals C and D.
- If not as specified, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION).
HO2S heater resistance
- 2-50 ohms
