AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZR-CD (RF Turbo)]
AIR FUEL RATIO (A/F) SENSOR INSPECTION [MZR-CD (RF Turbo)]
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Note
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• 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 WDS or equivalent, monitor the following:
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- Vehicle speed (PID: VSS)
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- Engine speed (PID: RPM)
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- 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.
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• If not within the specification, inspect the A/F sensor for an open or short circuit. (See A/F sensor circuit open/short inspection (sensor).) Then if there is no malfunction in the wiring harness, replace the front A/F sensor.
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- 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.
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• 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
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1-10 ohms
A/F sensor circuit open/short inspection (sensor)
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)
Open circuit
• If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
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- A/F sensor terminal A and PCM terminal 93
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- A/F sensor terminal B and PCM terminal 85
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- A/F sensor terminal C and PCM control relay terminal C
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- 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.
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- A/F sensor terminal A and body ground
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- A/F sensor terminal A and power supply
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- A/F sensor terminal B and body ground
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- A/F sensor terminal B and power supply
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- A/F sensor terminal C and body ground
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- A/F sensor terminal C and power supply
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- A/F sensor terminal D and body ground
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- A/F sensor terminal D and power supply
