Freestar V6-4.2L VIN 2 (2004)
Test B4-B5
Normal Operation
The DSM communicates with the diagnostic tool through the UART-based protocol (UBP) communications network circuit 2077 (PK/LB). If circuit
2077 (PK/LB) becomes open or shorted to ground, communications to that module will not be possible. Check circuit 2077 (PK/LB) 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 2077 (PK/LB), damage to the DLC C251, damage to the DSM C341c, or a problem in the in-line connectors.
The DSM fused power (overload protected) is supplied through the bussed electrical center (BEC) fuses: 10 (30A), circuit 566 (DG), and fuse 51
(10A) on circuit 1567 (RD/LB). The DSM ground circuits are circuit 1203 (BK/LB) and 1205 (BK).
Possible Causes
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BEC fuses:
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10 (30A)
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51 (10A)
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UBP circuit 2077 (PK/LB), shorted to ground or open
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circuit 1567 (RD/LB), open or shorted to ground
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circuit 566 (DG), open or shorted to ground
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circuit 1203 (BK/LB) open
