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Home >> Subaru >> 2015 >> BRZ Series.Blue, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Diagnostics (1 Of 3) >> DTC P2270 O2 Sensor Signal Biased/Stuck Lean (Bank 1 Sensor 2) >> Circuit figure >> Inspection steps
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Inspection steps

  1. Check oxygen sensor connector and intermediate connector.
    1. Disconnect the oxygen sensor connector and the intermediate connector.
    2. Check the connectors for ingress of water.

      NG: Completely remove water from the connectors.

      OK: Go to next step

  2. Check harness between engine control computer and oxygen sensor connector.
    1. Turn the ignition switch to OFF.
    2. Disconnect connectors from the engine control computer and the oxygen sensor.
    3. Measure the resistance between the engine control computer connector and the oxygen sensor connector.

      Result

      Result Go to
      Resistance between A36-6 -C13-1 and A34-21 -C13-3 is less than 1Ω A
      Resistance between A36-6 -C13-1 and A34-21 -C13-3 is 1Ω or more B

      B: Repair or replace the wire harness or connector (air/fuel ratio sensor - engine control computer)

      A: Go to next step

  3. Check harness between engine control computer and oxygen sensor connector.
    1. Connect connectors to the engine control computer.
    2. Turn the ignition switch to ON.
    3. Measure the voltage between the oxygen sensor connector and the engine ground.

      Result

      Result Go to
      Voltage between C13-3 and engine ground is less than 0.15 V. A
      Voltage between C13-3 and engine ground is 0.15 V or more. B

      B: Repair short in the power supply of wire harness or connectors or replace them (air/fuel ratio sensor - engine control computer).

      A: Go to next step

  4. Check the exhaust system.
    1. Check the exhaust system for loose parts, improper installation, and damage (such as cracks and holes).

      NG: Repair or replace the faulty parts.

      OK: Replacement of oxygen sensor