1992 Subaru SVXFACTORY OEM SERVICE PROCEDURE

By-Pass Air Control Valve (Loyale)

  1. With engine running, disconnect electrical connector. Engine speed should drop slightly with engine warm and significantly with engine cold. Reconnect electrical connector. Ensure engine returns to previous speed.
  2. If engine does not return to previous speed, turn engine off. Turn ignition switch to ON position. Ensure 10-12 volts are available at Black/White wire of Air Control Valve (ACV) electrical connector.
  3. Turn ignition off. Ensure resistance of ACV is 7.3-13.0 ohms at -4 to 176°F (-20 to 80°C). If resistance is not as specified, replace ACV. Check ACV solenoid for any short to ground. If short is present, replace ACV.
  4. Attach electrical connector to ACV. Disconnect connector at ECU. Turn ignition on. Ensure 10-12 volts are present at terminal No. 45 (Green/Red wire) of ECU connector. If voltage is not as specified, check harness between ACV and ECU.
  5. Turn ignition off, and reconnect ECU connector. Turn ignition on. Backprobe terminal No. 45 (Green/Red wire) of ECU. One volt or less should exist for about one minute after ignition switch is turned to ON position. After one minute, at least 10 volts should exist. If voltage is not as specified, check for a bad ground, problem with ECU circuits (sensors) or faulty ECU.
Chapter Navigation
Return to Chapter: Idle Control System
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.