Jeep WK2 Grand Cherokee Adaptive Bi-Xenon Headlamps

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Adaptive Bi-Xenon headlamps

The Adaptive Bi-Xenon headlamps were introduced for the 2014 model year, and discontinued (for unknown reasons) at the end of the 2015 model year. They will most like reappear on future models of the Grand Cherokee.

The adaptive forward lighting headlamps adjust up to 15 degrees to help illuminate the road around corners at night. These high-tech headlamps “follow” the steering wheel based on speed and steering angle to give you the advantage of seeing what’s up ahead. HID headlamps also assist the forward lighting feature and provide excellent lighting.

An additional benefit of adaptive headlights is that they prevent glare off the headlights for oncoming traffic. Also, if the car is going uphill or downhill, the headlights sense that and the bulbs will point downward/upward, again to help protect oncoming traffic from glare and “blinding.” When driving, oncoming traffic is usually on the left side of a vehicle and thus it is important when turning left to have headlights that do not point directly into oncoming traffic. As a vehicle turns right, there are no oncoming lanes to the right side of the car and in turn the light can shine at a larger angle. The headlamps also have a feature that auto-levels them when vehicle weight change occurs to maintain optimal aim. This feature is great for when you are turning corners because it lights the road ahead of you, rather than waiting for the light to catch up with you.

Bi-xenon adaptive HID headlights provide a very crisp and bright light, with a blue-tinted hue coming off the lights. These headlamps provide more light output than standard reflector lamps and also generate less heat, which is important in preventing the LED bulbs inside from burning out.

Vehicles equipped with the optional Adaptive Front Lighting System (AFLS) (which includes the features formerly known as the headlamp leveling system) are also equipped with an AFLS module. The AFLS module is attached to the passenger headlamp assembly.

This module works in conjunction with the front and rear axle (leveling) sensors, the headlamp leveling motors, the headlamp swiveling motors and electronic message inputs received over the Controller Area Network (CAN) data bus from other electronic modules in the vehicle. The module provides automatic headlamp beam aim adjustment to compensate for changes in vehicle height or direction caused by changes in vehicle loading, acceleration, deceleration, steering wheel angle and YAW rate.

Concealed within the module housing is the circuitry of the module itself, which includes a microcontroller. The module is connected to the vehicle electrical system through an integral connector receptacle by a take out and connector of the headlamp and dash wire harness.

Description

The AFLS module cannot be adjusted or repaired and, if ineffective or damaged, it must be replaced. The AFLS module is Flash programmable.

Operation

The microcontroller in the Adaptive Front Lighting System (AFLS) module contains the logic circuits and controls all of the features of the AFLS. The AFLS module also controls the functions previously performed by the Automatic Headlamp Leveling Module (AHLM). The AFLS module uses On-Board Diagnostics (OBD) and communicates with other electronic modules in the vehicle as well as with a diagnostic scan tool using the Controller Area Network (CAN) data bus. The AFLS module is also a Local Interface Network (LIN) master node and uses this method of communication to communicate with the two stepper motors within each right and left front lamp unit.

The AFLS module microcontroller continuously monitors electronic message inputs from the Body Control Module (BCM) (also known as the Common Body Controller/CBC), the Integrated Center Stack (ICS), the Steering Angle Sensor (SAS), the Steering Column Control Module (SCCM) microcontroller and the Controller Antilock Brake (CAB) (also known as the Antilock Brake Module/ABM, the Antilock Brake System/ABS module or the Electronic Stability Control/ESC module). The AFLS module also energizes or de-energizes the front and rear axle sensors as appropriate to monitor the vehicle height. When the axle sensors are energized, the AFLS module monitors and evaluates the Pulse Width Modulated (PWM) return signals from those sensors.

The AFLS module uses these inputs to determine steering wheel angle, vehicle speed, accelerator pedal position, vehicle yaw rate and ABS status. It then uses internal programming algorithms to compute the proper electronic message control outputs to provide over the LIN bus to the LIN slave headlamp leveling and headlamp swiveling stepper motors to adjust the headlamp beams vertically or horizontally as required. The AFLS module also continuously monitors return inputs from the leveling and swiveling motors to confirm stepper motor responsiveness as well as the proper positioning of the headlamp beams.

The AFLS module receives battery voltage on a fused ignition switch output (RUN) circuit, and is grounded at all times through a hard wired remote ground point. These connections allow the AFLS module to operate only when the ignition switch is in the ON position. The AFLS module also monitors all of the AFLS circuits and components, then sets active and stored Diagnostic Trouble Codes (DTC) for any monitored system faults it detects. The hard wired circuits of the AFLS module may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the AFLS module or the electronic controls or communication between modules and other devices that provide some features of the AFLS. The most reliable, efficient, and accurate means to diagnose the AFLS module or the electronic controls and communication related to AFLS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.