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Open Loop-2 Test

  1. With engine idling, disconnect 6-wire connector at MCU and test harness side terminal 7 for continuity to ground. There should be no continuity. If okay, proceed to Step  3. If not okay, continue to step 2)  .
  2. Disconnect 4-wire connector at vacuum switch assembly and test switch side terminal 7 for continuity to ground. There should be no continuity. If okay, repair short in harness between vacuum switch assembly and MCU. If not okay, proceed to step  4.
  3. Disconnect vacuum hose leading to blue switch and retest harness side terminal 7 for continuity to ground. There should be continuity. If okay, replace MCU. If not okay, disconnect 4-wire connector at vacuum switch assembly and test switch side terminal 7 for continuity to ground. There should be continuity. If okay, repair open in harness. If not okay, replace vacuum switch assembly.
  4. Disconnect vacuum hose leading to blue switch and check for vacuum. With engine at idle, there should be vacuum present. If okay, replace vacuum switch assembly. If not okay, repair vacuum leak or remove obstruction from hose.
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