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EGR System

  1. Disconnect vacuum hose from EGR valve (valve A) and, using a 3-way union, connect vacuum gauge to it. Check that engine starts and runs smooth at idle. See Fig 1.
  2. Check VSV with coolant temperature be below 135°F (57°C). Check that vacuum gauge indicates zero at 2500 RPM.
  3. With engine warm, check VSV and EGR vacuum modulator. Check that vacuum gauge indicates about 2.76 in. Hg at 2500 RPM. Check that vacuum gauge indicates zero at idle.
  4. Disconnect vacuum hose from EGR valve (valve B) and plug hose end. Apply vacuum and maintain a 23.62 in. Hg to valve B. Maintain engine speed at 2500 RPM. Release the vacuum.
    Fig 1: EGR System
    G41564Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Check that engine speed drops about 200 RPM. Disconnect vacuum gauge. Reconnect vacuum hoses to the proper location.
  6. To check EGR valve, stop engine. Remove EGR vacuum modulator exhaust gas hose and plug it. Start engine and race it once. Apply vacuum directly to EGR valve with engine idling.
  7. Engine should run rough or die. Reinstall EGR vacuum modulator. Reconnect vacuum hoses to proper location.
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