F 550 2WD Super Duty V10-6.8L (2009)
5. NOTE: The Vehicle Communication Module (VCM) prove-out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
-
Check the VCM connection to the vehicle.
-
Check the scan tool connection to the VCM.
-
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:
-
Verify the ignition key is in the ON position.
-
Verify the scan tool operation with a known good vehicle.
-
Refer to Information Bus to diagnose no response from the PCM.
7. Carry out the network test.
-
If the scan tool responds with no communication with the SJB, refer to Information Bus.
-
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, go to DTC Charts. For all other DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in
Body Control Systems. See: Diagnostic Trouble Code Descriptions 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
Interior Lighting
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
The SJB supplies voltage to the interior lighting system. The interior lighting system illuminates the courtesy lamps while a vehicle door is open or ajar.
The SJB controls all the interior lighting functions and timing by monitoring inputs from the door ajar switches, the instrument panel dimmer switch, and
the vehicle speed.
Interior Lamp Arbitrator
The interior lamp arbitrator (located in the SJB) chooses between the interior lighting, the interior mode, the interior lighting delay, the illuminated entry,
the illuminated exit, the battery saver, and the alarm flash processing to determine which feature has precedence of activating and deactivating the
interior lamps.
The features are prioritized as follows:
-
Battery saver
-
Manual interior lighting
-
Courtesy lighting
-
Courtesy lighting delay
-
Illuminated entry
-
Illuminated exit
Battery Saver
The battery saver relay is internal to the SJB and provides automatic shut-off of the demand lamps (vanity lamps, map lamps, and underhood lamp) and
the courtesy lamps after a time-out period in order to save battery voltage. A timer in the SJB is started when the ignition is turned to the OFF position.
When the time-out period for the lamps has elapsed, the voltage is automatically shut off to the lamps by the battery saver. While the battery saver has
voltage disabled, if the ignition is turned to any position other than off, any door becomes ajar, the key is removed from the ignition, a dome lamp is
turned on, a keypad unlock is received or the UNLOCK button of the RKE transmitter is pressed, the battery saver restores voltage and starts the timer
