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Self Test Output (STO)

NOTE: Enter this test only when codes cannot be retrieved or when directed by SELF TEST INPUT (STI)
Fig 1: STO & STI Connector Identification
G90F16530Courtesy of FORD MOTOR CO.
STO CIRCUIT PIN IDENTIFICATION

Circuit ECA Pin BOB Pin Wire Color
STO 17 1F Bl/W

1) Checking System Integrity  Visually check all wiring and connectors for evidence of damage, shorting or looseness. If a fault is found, repair as necessary. If no faults are found, go to next step.

2)  Install breakout box and leave ECA disconnected. Check for continuity between STO test pin and STO terminal of self-test connector. If continuity is not present, repair circuit between ECA and self-test connector. If continuity is present, go to step 3.

3)  Check for continuity between STO test pin and all other test pins. If continuity is present between STO test pin and another test pin, circuit is shorted. Repair as necessary. If continuity is not present, return to TESTS W/O CODES article.