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Oxygen Sensor Relay: Inspection

  1. Check that the oxygen sensor relay has no deformation, cracks or other damages.
  2. Measure the resistance between oxygen sensor relay terminals.
    Fig 1: Measuring Resistance Between Oxygen Sensor Relay Terminals
    G07909727Courtesy of SUBARU OF AMERICA, INC.
    Terminal No. Standard
    1 and 2 1 MΩ or more
    3 and 4 130.4 - 230.8 Ω (when 20°C (68°F))
  3. Connect battery positive terminal to terminal No. 3 and battery ground terminal to terminal No. 4, and measure the resistance between oxygen sensor relay terminals.
Fig 2: Measuring Resistance Between Oxygen Sensor Relay Terminals
G06344746Courtesy of SUBARU OF AMERICA, INC.
Terminal No. Standard
1 and 2 Less than 1 Ω
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