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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 Main Relay Terminals
    G08315468Courtesy of SUBARU OF AMERICA, INC.
    Terminal No. Standard
    1 and 2 1 MΩ or more
    3 and 4 93.8 - 136.4 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: Connecting Battery Positive Terminal To Terminal No. 3 And Battery Ground Terminal To Terminal No. 4
G08315469Courtesy of SUBARU OF AMERICA, INC.
Terminal No. Standard
1 and 2 Less than 1 Ω
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