Principles of Operation

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The time out for the battery saver relay and the accessory delay relay is 1 minute if the vehicle has less than 80 km (50 miles). For additional information on the battery saver relay, refer to INTERIOR LIGHTING article. Once the vehicle passes the approximate mileage threshold of 80 km (50 miles), the time out for both relays will be the normal 10 minute time out, as described by the Owner's Literature. For the accessory delay relay, refer to GLASS, FRAMES AND MECHANISMS article.

NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).

The SJB is a multifunction control module that controls many of the vehicle systems. Several SJB functions utilize hardwired inputs and/or outputs. The SJB controls the following hardwired functions, using the corresponding inputs and outputs:

Function	Input(s)	Output(s)
Autolamps	Headlamp switch Sunload sensor	Headlamps (low beam)
Daytime running lamps (DRL) (if equipped)	Headlamp switch Park brake switch	Headlamps (low beam)
Exterior lighting	Headlamp switch Hazard lamp switch	Exterior lamps/turn signal bulbs Trailer tow connector
Fog lamps (if equipped)	Fog lamp switch	Fog lamp relay
Headlamps	Headlamp switch	Headlamps (low and high beam)
Horn	Horn switch Integrated keyhead transmitter (IKT)	Horn relay (integral to SJB)
Interior lighting	Door ajar switches Liftgate ajar switches IKT	Interior lamps relay
One-touch down driver window	Master power window switch	One-touch down relay
Power door locks	Ignition switch IKT Keyless entry keypad Door lock control switches	Door lock/unlock relays
Power windows	Master window control switch Passenger window control switch	Window motors
Heated rear window	Heated rear window switch	Heated rear window relay Heated rear window indicator
Rear windshield wiper	Wiper/washer switch	Rear wiper motor relay Rear washer pump motor

In addition, the SJB is involved in other vehicle systems through communication over the controller area network (CAN). For a detailed list of SJB network inputs and outputs, refer to MODULE COMMUNICATIONS NETWORK article.

Some SJB parameters are programmable. Two types of programmable parameters are available: vehicle configuration and customer preference. Refer to MODULE CONFIGURATION article for additional information on programmable parameters.

The SJB utilizes a protective circuit strategy for many of its outputs (for example, the headlamp output circuit). Output loads (current level) are monitored for excessive current (typically short circuits) and are shut down (voltage or ground provided by the module is turned off) when a fault is detected. A continuous DTC is stored at that time for the fault. The circuit will then reset after an ignition cycle or customer demand of the function (which will switch the component on, causing the 30-minute battery saver timer to be energized). When an excessive circuit load occurs several times, the module shuts down the output until a service procedure is carried out. At the same time, the continuous DTC that was stored on the first failure will not clear by a command to clear the continuous DTCs. The module will not allow this code to be cleared or the normal circuit function restored, until a successful on-demand self-test proves that the fault has been repaired. After the on-demand 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.

DTC B106E sets when the SJB has disabled a circuit due to a repetitive fault causing a circuit overload. A corresponding DTC for the circuit in question will also be set as follows:

DTC B1034 - Radio Start Signal Circuit Failure
DTC B1218 - Horn Relay Coil Circuit Short to Vbatt
DTC B1304 - Accessory Delay Relay Coil Circuit Short To Battery
DTC B1316 - Battery Saver Relay Coil Circuit Short To Ground
DTC B1349 - Heated Backlite Relay Short To Battery
DTC B1474 - Battery Saver Power Relay Circuit Short To Battery
DTC B1502 - Lamp Turn Signal Left Circuit Short To Ground
DTC B1506 - Lamp Turn Signal Right Circuit Short To Ground
DTC B1626 - Lamp Keypad Output Short Circuit To Ground
DTC B2070 - Trailer Tow Relay Coil(s) Circuit Failure
DTC B2501 - LF Lamp Low Beam Circuit Failure
DTC B2503 - RF Lamp Low Beam Circuit Failure
DTC B2505 - LF Lamp High Beam Circuit Failure
DTC B2507 - RF Lamp High Beam Circuit Failure
DTC B2512 - Front Fog Lamp Relay Ckt Short to Battery
DTC C1788 - Stoplamp Relay Output Circuit Short to Ground
DTC C1961 - Park Lamp Relay Coil Circuit Failure
DTC P0930 - Gear Shift Lock Solenoid Circuit Low