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Key On/Engine Off (KOEO) Self-Test Procedure

  1. This is a static check of processor input and output circuits. Connect STAR tester or VOM to vehicle Self-Test connector. See Fig 1 for correct VOM connections. Turn ignition switch to ON position to start Self-Test. DO NOT  depress throttle during test. Observe and record all On Demand and Continuous/Memory service codes.
  2. If any codes appear, refer to the proper test shown in the reference table for that specific engine. Start with the first code displayed. If the tests refer you to other checks, perform them as instructed. When more than 1 code is displayed, repair problems in the order that codes are displayed.
NOTE: When any repair has been completed, QUICK TEST must be repeated BEFORE attempting to repair any other problems identified by service codes. Proceed with repairs as indicated by Key ON/Engine OFF Self-Test Results table and then by On Demand Codes table.
Fig 1: Analog VOM Hook-Up for Reading Codes This applies to all models.
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