Mazda 2: Air Fuel Ratio (A/F) Sensor
AIR FUEL RATIO (A/F) SENSOR 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 A/F sensor connector.
4. Remove the A/F sensor using the SST.

5. Install in the reverse order of removal.
AIR FUEL RATIO (A/F) SENSOR INSPECTION
A/F Sensor 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)
- A/F sensor current (PID: O2S11)
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 A/F sensor current (PID: O2S11) is 0.25 mA or more while
decelerating as
shown in the figure.

- If not as specified, replace the A/F sensor. (See AIR FUEL RATIO (A/F)
SENSOR REMOVAL/INSTALLATION).
A/F Sensor Heater Inspection
1. Disconnect the A/F sensor connector.
2. Measure the resistance between A/F sensor terminals C and D.

- If not as specified, replace the A/F sensor. (See AIR FUEL RATIO (A/F)
SENSOR REMOVAL/INSTALLATION).
A/F sensor heater resistance
READ NEXT:
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 syst
CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION
CAUTION:
When replacing the CKP sensor, make sure there is no foreign material on
it such as
metal shavings. If it is installed with foreign
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 ma
SEE MORE:
LIGHTING SYSTEMS LOCATION INDEX
Back-up light switch
Front combination light
Auto light sensor
Side turn light
Front fog light
Cargo compartment light
Rear combination light
High-mount brake light
License plate light
Interior light
Hazard warning switch
Light switch
Combination switc
WARNING
When removing the fuel-fi ller cap,
loosen the cap slightly and wait for any
hissing to stop, then remove it:
Fuel spray is dangerous. Fuel can
burn skin and eyes and cause illness
if ingested. Fuel spray is released
when there is pressure in the fuel tank
and the fuel-fi ller cap is
© 2016-2022 Copyright www.m2info.net
