Circuit Test STO - Self-Test Output

Fig 1: STO Terminal at Self-Test Connector ID

NOTE: Enter this test only when instructed by CIRCUIT TEST STI.

CIRCUIT PIN IDENTIFICATION

Circuit	Breakout Box Pin No.	ECA Pin	Wire Color
STO	17	1F	White/Black

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 next step.

2) Install breakout box, and leave ECA disconnected. Measure resistance between STO test pin and STO diagnostic connector terminal. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair circuit between ECA and STO diagnostic connector.

3) Measure resistance between STO test pin and all other test pins. If resistance between STO test pin and any other test pin is less than 5 ohms, circuit is shorted. Repair as necessary. If resistance between STO test pin and all other test pins is greater than 5 ohms, check ECA power and ground circuits.