2016 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE

Camshaft Position Sensor (Method With Oscilloscope)

  1. Disconnect the ground terminal from battery sensor. < Ref. to BATTERY , NOTE, Note. >
  2. Prepare an oscilloscope.
  3. Remove the engine control module (ECM). < Ref. to REMOVAL , Engine Control Module (ECM). >
  4. Install the ST between the ECM and bulkhead harness and the engine harness. < Ref. to CAUTION , General Descriptions

    ST 18460AA030 CHECK BOARD

  5. Connect the ground terminal to battery sensor. < Ref. to BATTERY , NOTE, Notes
  6. Connect the probe to ST.
    • Intake camshaft position sensor
      Fig 1: Connecting Ground Terminal To Battery Sensor - Intake Camshaft Position Sensor
      G10291249Courtesy of SUBARU OF AMERICA, INC.
    • Exhaust camshaft position sensor
      Fig 2: Connecting Ground Terminal To Battery Sensor - Exhaust Camshaft Position Sensor
      G10291250Courtesy of SUBARU OF AMERICA, INC.
      Camshaft position sensor Terminal No. Probe
      Intake RH 20 +
      LH 21 +
      Exhaust RH 32 +
      LH 33 +
      RH and LH 34 -
  7. Start the engine and let it idle.
  8. Check the waveforms and voltage.
    NOTE: For waveform and voltage, refer to "Engine Control Module (ECM) I/O Signal". < Ref. to ENGINE CONTROL MODULE (ECM) I/O SIGNAL . >
  9. After inspection, install the related parts in the reverse order of removal.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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