F 250 2WD Super Duty V10-6.8L (2009)
7. Carry out the network test.
-
If the scan tool responds with no communication for one or more modules, 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 See:
Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) Chart. See: Diagnostic Trouble Code Descriptions/Smart Junction Box
(SJB)
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
Smart Junction Box (SJB)
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
NOTE: The time out for the battery saver relay and the accessory delay relay (both are controlled by the SJB) is one minute if the vehicle has less than
80 km (50 miles). Once the vehicle passes the approximate mileage threshold of 80 km (50 miles), the time out for both relays is 10 minutes, as
described by the Owner's Literature. For the battery saver relay, refer to Courtesy Lamp. For the accessory delay relay, refer to Windows. See: Lighting
and Horns/Courtesy Lamp/Testing and Inspection
The SJB communicates via the Medium Speed Controller Area Network (MS-CAN).
The SJB controls the power door lock system. The SJB monitors the door lock/unlock switch inputs from the interior door lock switches. When the SJB
receives an unlock/lock command from any door lock control switch, the module activates the door lock actuators.
The SJB also controls the following remote lock/unlock features:
-
Remote Keyless Entry (RKE) transmitter lock/unlock
-
Panic alarm (button is part of the RKE transmitter)
-
Keyless entry keypad
The SJB controls the autolamp subsystem. The autolamp subsystem provides light-sensitive automatic on/off control of the headlamps and parking
lamps.
The SJB controls the battery saver, delayed accessory function, exterior and interior lighting and the horn.
The SJB controls the Tire Pressure Monitoring System (TPMS).
Field-Effect Transistor (FET) Protection
The SJB utilizes a Field-Effect Transistor (FET) protective circuit strategy for many of its outputs (for example, the headlamp output circuit). Output
loads (current level) are monitored for excessive current (typically shorted circuits) and are shut down (turn off the voltage or ground provided by the
module) when a fault is detected. A continuous DTC is stored at that time for the fault.
The circuit will reset after a customer demand (ignition cycle) of the function (which will switch the component on, causing the 30-minute battery saver
timer to be energized). When an excessive circuit load (from a shorted circuit) occurs several times, the module shuts down the output until a repair
procedure is carried out. At the same time, the continuous DTC that was stored by the first failure will not clear by a command to clear the continuous
DTCs.
The SJB will not allow the DTC to be cleared or the normal circuit function restored until a successful self-test (retrieving on-demand DTCs) proves that
the fault has been repaired. After the self-test has successfully completed (no on-demand DTCs present), the continuous DTC will have been cleared and
the normal circuit function will be restored.
The SJB has three predefined levels of short circuit tolerance established. When the first or second level is reached, the continuous DTC associated with
the short circuit sets along with DTC B106E. These DTCs (B106E and the DTC associated with the shorted circuit) may be cleared using the Clear DTC
operation on the scan tool as long as the fault itself has been corrected. Each and every time the scan tool retrieves DTCs from the module and a circuit is
shorted, a level of short circuit tolerance is used up.
