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Engine Main Relay: Inspection

  1. Remove relay box cover. 
  2. Remove engine main relay.  (Marking: ENGINE MAIN).
    Fig 1: Identifying Engine Main Relay
    G03138834Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Inspect relay continuity. 
    1. Using an ohmmeter, check that there is continuity between terminals 3 and 5. If there is no continuity, replace the relay.
    2. Check that there is continuity between terminals 2 and 4. If there is no continuity, replace the relay.
    3. Check that there is no continuity between terminals 1 and 2. If there is continuity, replace the relay.
    Fig 2: Checking Engine Main Relay Continuity (No Power Applied)
    G03138835Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Inspect relay operation. 
    1. Apply battery positive voltage across terminals 3 and 5.
    2. Using an ohmmeter, check that there is no continuity between terminals 2 and 4. If there is continuity, replace the relay.
    3. Check that there is continuity between terminals 1 and 2. If there is no continuity, replace the relay.
    Fig 3: Checking Engine Main Relay Continuity (Power Applied)
    G03138836Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Reinstall engine main relay. 
  6. Reinstall relay box cover. 
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