F 150 4WD V8-4.6L VIN 8 (2010)
Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. See: Diagrams/Electrical
Diagrams/Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following:
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Fuse
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Wiring, terminals or connectors
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SJB
PINPOINT TEST I: THE SJB DOES NOT RESPOND TO THE SCAN TOOL
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the
connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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I1 CHECK THE SJB VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
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Ignition ON.
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NOTE: Measurements are taken with the fuses installed.
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Measure the voltage between the SJB fuse 5 (10A) and ground.
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Is the voltage greater than 10 volts?
Yes
GO to I2.
No
VERIFY the SJB fuse 5 (10A) is OK. If OK, GO to I4. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
See: Diagrams/Electrical Diagrams/Diagrams By Number
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I2 CHECK THE SJB GROUND CIRCUITS FOR AN OPEN
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Ignition OFF.
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Disconnect: Negative Battery Cable.
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Disconnect: SJB C2280d.
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Measure the resistance between the SJB C2280d-8, circuit GD139 (BK/YE), harness side and ground; and between the SJB C2280d-12, circuit
GD139 (BK/YE), harness side and ground.
