F 150 2WD Pickup V8-5.4L SOHC VIN 5 (2004)
Test D3-D5
Normal Operation
The DSM receives power through the central junction box (CJB) fuse 109 (30A) and fuse 3 (5A). From the fuses power is delivered to the module
through circuits 566 (DG) and 956 (OG/LG), and is grounded on circuits 875 (BK/LB) and 57 (BK).
The DSM communicates with the diagnostic tool through the UART based protocol (UBP) communications network circuit 1906 (VT). If circuit 1906
(VT) becomes open or shorted to ground communications to that module will not be possible. Check circuit 1906 (VT) between the DSM C341c and
the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in circuit 1906 (VT),
damage to the DLC C251, damage to the DSM C341c, or a problem in the in-line connector.
Possible Causes
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circuit 1906 (VT) shorted to ground or open
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circuit 956 (OG/LG) open
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circuit 566 (DG) open
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circuit 875 (BK/LB) open