Principles of Operation
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
Normal Operation
When a repetitive fault causing a circuit overload is detected on certain output circuits, the smart junction box (SJB) disables the circuit by removing voltage, or ground, to the affected circuit. The circuit remains disabled until the fault is corrected and an on-demand self-test is run. When the on-demand self-test has been run after all faults have been corrected, any DTCs related to the fault are cleared.
DTC B106E sets when the SJB has disabled a circuit due to a repetitive fault causing a circuit overload. For a complete list of corresponding DTCs, refer to Principles of Operation .
DTC B106F sets when one or more output functions are permanently disabled due to a repetitive circuit overload fault. When DTC B106F is present, the SJB must be replaced after the fault condition has been corrected.
Possible Causes
- Output circuit short to ground or voltage
- SJB