Mustang V8-5.4L SC (2008)
Body Control Systems: Initial Inspection and Diagnostic Overview
Inspection and Verification
INSPECTION AND VERIFICATION
1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage.
VISUAL INSPECTION CHART
Electrical
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Bussed electrical center (BEC) fuse(s):
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59 (30A)
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63 (30A)
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67 (30A)
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68 (20A)
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Wiring, terminals or connectors
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Smart junction box (SJB)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the data link connector (DLC).
5. NOTE: The vehicle communication module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
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Check the VCM connection to the vehicle.
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Check the scan tool connection to the VCM.
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Refer to Information Bus (Module Communications Network), No Power To The Scan Tool, to diagnose no communication with the scan tool.
6. If the scan tool does not communicate with the vehicle:
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Verify the ignition key is in the ON position.
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Verify the scan tool operation with a known good vehicle.
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Refer to Information Bus (Module Communications Network) to diagnose no response from the PCM.
7. Carry out the network test.
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If the scan tool responds with no communication for one or more modules, refer to Information Bus (Module Communications Network).
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If the network test passes, retrieve and record the continuous memory DTCs.
8. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB.
9. NOTE: In order to properly run the self-test, the convertible top (if equipped) must be in the full-down position and the doors must be closed. If
these conditions are not met, DTCs B1141, B1142, B1319 and/or B1327 may be set. In this case, they would be product characteristic and
diagnostics should not be followed for these DTCs at this time. Clear the DTCs. Repeat the self-test with the convertible top (if equipped) in the
full-down position and both doors closed.
If the DTCs retrieved are related to the concern, go to Diagnostic Trouble Code (DTC) Chart. See: Diagnostic Trouble Code Descriptions
10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. See: Symptom Related Diagnostic Procedures
Principles Of Operation
PRINCIPLES OF OPERATION
NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).
The SJB is a combination of a multifunction control module and an interior fuse panel. The SJB functions control multiple vehicle systems which
include:
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Battery saver
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Convertible top (if equipped)
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Convertible top drop window function (if equipped)
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Exterior lighting
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Heated rear window
