1995 Toyota Tercel Base, AutomaticFACTORY OEM SERVICE PROCEDURE

EGR Vacuum Modulator

NOTE: When testing EGR vacuum modulator, it will be necessary to monitor engine RPM by using tachometer or scan tester depending on model application. For tachometer or scan tester connections, see IDLE SPEED & MIXTURE in the ADJUSTMENTS article.
  1. Mark vacuum hose locations and disconnect vacuum hoses from EGR vacuum modulator. Block ports "P" and "R" on EGR vacuum modulator. See Figure.
    NOTE: Ports "P" and "R" are the double ports on side of EGR vacuum modulator. Port "Q" is single port on side of EGR vacuum modulator.
  2. Apply air pressure to port "Q". See Figure. Air should pass freely through air filter side of EGR vacuum modulator.
  3. Start and operate engine at specified RPM. See EGR VACUUM MODULATOR TESTING SPECIFICATIONS  table. Repeat test procedures in steps 1) and 2). Strong resistance of airflow should be felt. Replace EGR vacuum modulator if resistance is not felt. Reconnect vacuum hoses to proper locations.
EGR VACUUM MODULATOR TESTING SPECIFICATIONS

Application Engine RPM
Tercel 2500
Factory Service Tools

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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.