F 350 2WD Super Duty V10-6.8L (2009)
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, No Power To The Scan Tool, to diagnose no power to 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 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.
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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: Testing and Inspection. For all other
DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in Body Control Systems. See: Body and Frame/Body Control Systems/Testing and
Inspection/Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) Chart
10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. See: Symptom Related Diagnostic Procedures
Principles of Operation
Parking, Rear and License Plate Lamps
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
The SJB monitors the headlamp switch position by sending voltage reference signals on multiple circuits to the headlamp switch. There is one circuit for
each headlamp switch position. At any given time, one of the signal circuits is routed to ground.
If the SJB does not detect any of the inputs to the headlamp switch is active (routed to ground) for 5 seconds, the SJB turns on the exterior lights and
keeps them on for 10 minutes after the ignition switch is turned off (or 10 minutes from the time the SJB does not detect any headlamp switch input if the
ignition switch was already off). Additionally, if the SJB detects multiple circuits short to ground, the SJB implements a planned strategy depending on
the multiple inputs received. Based on the multiple inputs received, the autolamps, the headlamps and/or the parking lamps are turned on.
If either of these situations occur, the SJB should not be ruled immediately as being at fault. This is normal behavior of the SJB design as it has detected
a fault with the inputs from the headlamp switch.
When the SJB receives an input from the headlamp switch indicating a request for the parking lamps, the SJB energizes the parking lamp relay (internal
to the SJB), which supplies voltage to the exterior lamps.
