Mountaineer RWD V6-4.0L (2008)
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Battery junction box (BJB) fuses:
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1 (50A)
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2 (50A)
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3 (50A)
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Smart junction box (SJB) fuse 2 (5A)
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Wiring, terminals or connectors
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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. If the DTCs retrieved are related to the concern, refer to the 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/Smart Junction Box (SJB)
Principles of Operation
PRINCIPLES OF OPERATION
NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).
The SJB receives inputs and delivers outputs to electronically-controlled features of the vehicle. The SJB constantly monitors the systems under its
control and reports a concern in the form of a DTC. The DTC can be retrieved with a scan tool through the medium speed controller area network
(MS-CAN).
