1990 Lexus ES 250 AutomaticFACTORY OEM SERVICE PROCEDURE

EGR System

  1. Remove filters from EGR vacuum modulator. See Fig 1. Using compressed air, clean filters. Install filters with coarse side facing outside.
    Fig 1: Identifying ES250 EGR System Components
    G90B18862Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Using a vacuum tee, connect a vacuum gauge between EGR vacuum hose and EGR valve. To ensure EGR valve is seating, start engine and check idle quality. If EGR valve is not seating, replace EGR valve.
  3. With coolant temperature less than 104°F (40°C), vacuum gauge should indicate zero vacuum at 2500 RPM. Warm engine to operating temperature. Raise engine speed to 2500 RPM. Vacuum gauge should indicate low vacuum.
  4. Disconnect vacuum hose from port "R" of EGR vacuum modulator. See Fig 1. Connect port "R" directly to intake manifold using another vacuum hose. Vacuum gauge should indicate high vacuum with engine at 3500 RPM.
  5. Engine may misfire slightly. Let engine idle. Remove vacuum gauge and reconnect all vacuum hoses. Disconnect vacuum hose from EGR valve. Apply vacuum directly to EGR valve. Engine should run rough or stall.
  6. Turn engine off. Identify and disconnect all vacuum hoses from EGR vacuum modulator. Block ports "P" and "R" with finger. See Fig 1. Blow air into port "Q". Air should flow freely out of filter.
  7. Start engine and run engine at 3500 RPM. Block ports "P" and "R" with finger. Blow air into port "Q". Air should not flow out of filter. If air flows out of filter, replace EGR vacuum modulator.
  8. Turn engine off. Drain coolant from radiator. Remove Bimetallic Vacuum Switching Valve (BVSV). See Fig 1. With BVSV less than 104°F (40°C), blow air into top port. Air should not pass through BVSV.
  9. Heat BVSV to 129°F (54°C). Blow air into top port. Air should pass through BVSV. If BVSV does not operate as outlined, replace BVSV.
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.

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