Ranger 4WD V6-4.0L (2009)
Daytime Running Lamp: Initial Inspection and Diagnostic Overview
Special Tools Used With Diagnostics
Daytime Running Lamps (DRL)
Principles of Operation
Daytime Running Lamps (DRL)
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
NOTE: The Daytime Running Lamps (DRL) is not a programmable parameter for this vehicle.
The DRL are controlled by the SJB. The SJB operates the low beam headlamps at a reduced intensity when the following conditions are met:
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The high beam headlamps are not on
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The ignition switch is in the RUN position
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The parking brake is not engaged
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 short circuits) and are shut down (turns off the voltage or ground provided by the
module) when a fault event is detected. A continuous DTC is stored at the fault event and a cumulative counter is started.
When the demand for the output is no longer present, the module resets the FET circuit protection. The next time a request activates a circuit that has
been shut down by a previous short (FET protection) and the circuit remains shorted, the FET protection shuts off the circuit again and the cumulative
counter advances.
When the excessive circuit load occurs often enough, the module shuts down the output until a repair procedure is carried out. Each FET protected
circuit has 3 predefined levels of short circuit tolerance based on the harmful effect of each circuit fault on the FET and the ability of the FET to
withstand it. A total level of fault events is established based upon the durability of the FET. If the total tolerance level is determined to be 600 fault
events, the 3 predefined levels would be 200, 400 and 600 fault events.
When each tolerance level is reached, the continuous DTC that was stored on the first failure cannot be cleared by a command to clear the continuous
DTCs. The module does not allow this code to be cleared or the circuit restored to normal operation until a successful self-test proves that the fault has
been repaired. After the self-test has successfully completed (no on-demand DTCs present), the continuous DTC automatically clears and the circuit
function returns.
When the first or second level is reached, the continuous DTC (associated with the short circuit) sets along with DTC B106E. These DTCs can be
cleared using the module self-test, then the Clear DTC operation on the scan tool as long as the fault itself has been corrected.
If the number of short circuit fault events reach the third level, then DTCs B106F and B1342 set along with the associated continuous DTC. This DTC
cannot be cleared and the module must be replaced.
The SJB FET protected output is the DRL output within the SJB. The low beam circuit themselves are protected by SJB fuses 3 (10A) and 4 (10A).
