AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZR-CD (RF Turbo)]

id0140f1899600

Note
•  Before performing the following inspection, make sure to follow the troubleshooting flowchart.

A/F Sensor Current 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.

am3zzw00004090

•  If not within the specification, inspect the A/F sensor for an open or short circuit. (See A/F Sensor Circuit Open/Short Inspection.) Then if there is no malfunction in the wiring harness, replace the A/F sensor.
―  If there is no open/short circuit, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)


A/F Sensor Heater Resistance Inspection

1.  Disconnect the A/F sensor connector.

2.  Measure the resistance between A/F sensor terminals C and D.

am3zzw00004091

•  If not within the specification, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)
A/F sensor heater resistance
1—10 ohms


A/F Sensor Circuit Open/Short Inspection

1.  Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)

2.  Disconnect the A/F sensor connector.

3.  Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

am3zzw00004756

Open circuit
•  If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
―  A/F sensor terminal A and PCM terminal 93
―  A/F sensor terminal B and PCM terminal 85
―  A/F sensor terminal C and PCM control relay terminal C
―  A/F sensor terminal D and PCM terminal 34
Short circuit
•  If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.
―  A/F sensor terminal A and body ground
―  A/F sensor terminal A and power supply
―  A/F sensor terminal B and body ground
―  A/F sensor terminal B and power supply
―  A/F sensor terminal C and body ground
―  A/F sensor terminal C and power supply
―  A/F sensor terminal D and body ground
―  A/F sensor terminal D and power supply