2023 Subaru Ascent BaseFACTORY OEM SERVICE PROCEDURE

Camshaft Position Sensor

  1. Disconnect the ground terminal from battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
  2. Prepare an oscilloscope.
  3. Disconnect the connector from ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM)>REMOVAL .
  4. Attach the ST between the ECM, engine harness and the bulkhead wiring harness. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

    Special tool: 

    CHECK BOARD (18460AA190)

  5. Connect the probe to ST.
    G16438553Courtesy of SUBARU OF AMERICA, INC.
    G16438548Courtesy of SUBARU OF AMERICA, INC.
    Camshaft position sensor Terminal No. Probe
    Intake RH (E158) No. 56 +
    LH (E158) No. 57 +
    Exhaust RH (E158) No. 24 +
    LH (E158) No. 40 +
    RH and LH (B134) No. 63 -
  6. Connect the ground terminal to battery sensor. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
  7. Start the engine and let it idle.
  8. Check the waveforms and voltage.
    NOTE: For waveform and voltage, refer to "Control Module (ECM) I/O Signal". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>CONTROL MODULE I/O SIGNAL>ELECTRICAL SPECIFICATION .
  9. After inspection, install the related parts in the reverse order of removal.
    NOTE: For installation procedures of ECM connectors, refer to Engine Control Module (ECM). Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM)>INSTALLATION .
Chapter Navigation
Return to Chapter: Inspection
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

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.