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Test STO - Self-Test Output

NOTE: Enter this test only when codes cannot be retrieved, or when instructed by CIRCUIT TEST STI.
Fig 1: Identifying STO Connector Terminals
G91D08149
CIRCUIT PIN IDENTIFICATION

Circuit Breakout Box Pin ECA Pin
STO 17 1F

1) Checking System Integrity  Visually check all wiring and connectors for evidence of damage, shorting or looseness. If fault is found, repair as necessary. If no fault is found, go to step 2).

2)  Install breakout box and leave ECA disconnected. Check for continuity between STO test pin and STO diagnostic connector terminal. If continuity is not present, repair circuit between ECA and STO diagnostic 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 other test pin(s), circuit is shorted. Repair as necessary. If continuity is not present, return to TESTS W/O CODES article.