BMW LED lamps: Useful information, repair instructions and practical tips

The G30 (saloon) and G31 (touring) models of the BMW 5 series are equipped with ultra-modern LED lamps, which offer a number of advantages. These lamps use LED technology for low beam and high beam, resulting in improved visibility and also a striking appearance. The different headlamp variants offer adaptive functions that adjust the light distribution depending on the driving situation. This increases safety for night-time driving.

The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for suitably qualified personnel only.

Adaptive LED lamp 1. BI-LED module, 2. Matrix module, 3. Dynamic cornering light, 4. Lamp unit for daytime running light, position light and direction indicator light, 5. Lamp unit for daytime running light and position light

BMW LED lamps: Differences, functions and advantages of the variants on offer

Depending on the vehicle equipment and the models found in individual countries, the following lamp variants can be installed.

LED lamps with adaptive dynamic cornering light
Adaptive LED lamp
LED lamps with laser light

The standard LED lamps with BI-LED modules are characterised by a U-shaped daytime running light. In comparison, the adaptive LED lamps have L-shaped daytime running lights. For this variant, HELLA has developed an LED matrix module with twelve channels, a system which enables dynamic light functions. In the top variant with laser light, HELLA has also integrated a dynamic laser in the headlamp in addition to the LED matrix module. The individually controllable matrix elements generate extremely precise and highly variable light distribution in order to illuminate the road area, thus ensuring better visibility in the dark.

BMW LED lamps - design and function — The following schematic diagram shows an example of the internal structure of an LED lamp with laser light. 1. Side marker light (USA), 2. Direction indicator LED module, 3. Parking light/daytime running light, exterior, 4. Parking light/daytime running light, interior, 5. Accent lamp, 6. Laser light, 7. BI-LED module, 8. Matrix LED module, 9. Cornering light, 10. Fan 1, 11. Fan 2, 12. Servomotor headlamp levelling, 13. Servomotor adaptive dynamic cornering light, terminal 30 power supply (+), terminal 31 earth connection, K-CAN data bus, SIG redundant signal line direction indicator, ECU front light electronics

BMW LED lamp technology: Design, components and functioning in detail

The adaptive LED lamps consist of several LED modules that are responsible for the low beam, high beam, daytime running light, side marker light and direction indicator functions. All necessary light functions are controlled by the relevant front light electronics on request from the master control unit (body domain controller). The low beam and high beam are shown by a Bi-LED module and a matrix module. With its powerful LEDs, the Bi-LED module brings about illumination in the area in front of the vehicle and also creates part of the high beam. The matrix module with its 12 LEDs is responsible for the low beam and high beam. Daytime running light, position light and direction indicator light are each effected via separate LED modules. At the same time the front light electronics also control the temperature in the lamp. As a result of the input values provided by several temperature sensors in the lamp, by the driving speed and the outside temperature, the lamp fan motors are controlled as required. After the switching off of all light functions, the fans can continue to run in order to prevent condensation forming on the lamps.

Optimum illumination with BMW LED lamps: All light functions at a glance

The LED lamps offer a variety of light functions that make driving at night safer and more comfortable. These functions include the following:

Parking light / daytime running light: Clear view and modern design

The parking light and daytime running light functions are generated via a separate LED module and then forwarded to the relevant lamp unit. Depending on the lamp model, one or more modules can be installed, modules which are directly connected to the control unit in the lamp. The LED module is electrically controlled via a pulse-width modulated signal.

Cornering light: More safety at bends and junctions

Additional light immediately in front of the vehicle that switches on during cornering manoeuvres to improve visibility in the selected direction.

Glare-free high beam: Automatic light control for better visibility

The glare-free high beam is only available with the variant options "Adaptive LED lamps" and "LED lamps with laser light". While this function is in operation, the high beam inside the lamp is switched off for wide-area illumination. Depending on the driving speed, the external high beam and the laser light are switched on automatically and generate a "partial high beam". The light beam is limited inwards by a fixed cover, thus creating a vertical cut-off line. In such a case, the area between the two vertical cut-off lines of the LED lamps is not illuminated and is therefore glare-free. Thanks to the integrated stepper motor for the dynamic cornering light, each LED lamp can still be adjusted by 15°. This allows a glare-free range of 5° to 7° to be set when oncoming traffic approaches. The high beam is switched on at speeds above 40 km/h and switched off at speeds below 30 km/h.

High-beam assistant: Intelligent light regulation for more driving comfort

If the light from the lamps of an oncoming vehicle is detected by the front camera, the control unit of the high-beam assistant sends a CAN signal to the body domain controller (BDC) to switch off the high beam. The high-beam assistant function can also be integrated into the control unit for camera-based assistance systems depending on the equipment features available.

The laser module is located next to the LED matrix module.

Laser light: Maximum range for safe driving at night

The laser unit is integrated into the adaptive LED lamp next to the LED matrix module.
Within this laser unit, blue laser light from high-power diodes is converted into very intense white light via a phosphorus element. The laser unit generates a concentrated spot with high visibility. Thanks to the combination of LED and laser technology, the high beam can therefore achieve a range of up to 600 m. This doubles the range of the LED high beam. When the high-beam assistant is switched on, the laser light is then switched on from a speed of approx. 60 km/h via the front light electronics and it functions as an additional high beam depending on the speed reached. It is switched off after a short delay once the speed falls below 55 km/h. In addition, the laser is already active in the case of partially dimmed segments, thus extending the illumination range of the low beam.

BMW LED light functions: Optimum illumination for maximum safety

Each LED lamp is connected directly to the body domain controller (BDC) via its control unit (front light electronics). Depending on the request from the BDC control unit, the appropriate light functions are carried out by the relevant front light electronics. Communication takes place via a CAN bus signal. Any faults occurring in the lamp are recognised by the front light electronics and stored in the BDC control unit. They can be read out via the on-board diagnostics by using a suitable diagnostic device. In addition, a check control message is displayed in the instrument cluster if a lamp fails. The body domain controller automatically performs a component check on the lamps after the ignition has been switched on. If the light is also switched on, a defective light-emitting diode can be detected by the measuring of the current of the individual lamp outputs (heat monitoring).

Maintaining and repairing BMW LED lamps: Important information for the workshop

In the event of a repair, it can happen that components with different software or hardware numbers may be installed. This means that new components are mixed with old ones already in the vehicle. In such cases, it is imperative for all components to be harmonised. Depending on the vehicle model, lamp type and the individual control unit, additional service work must be carried out with a suitable diagnostic tool in order to ensure the correct functioning of the lighting system. If an LED lamp is replaced, the data matrix code has to be read out from the new lamp and written to the control unit in accordance with the vehicle manufacturer's repair instructions. What this means in detail is explained below as an example but without the description of detailed processes.

BMW LED lamps - data matrix code — Description: The data matrix code is located on the housing of the lamp near the type plate. The code should be photographed before the lamp is installed.

Data matrix code: Coding and adaptation of LED lamps

Each light function in the lamp has a so-called classification resistor. Depending on the classification resistor, each LED component is controlled individually by the control unit. This ensures that a constant quality of light is achieved with consistent brightness and colour. The data matrix code is the new form of classification and it is affixed to the lamp housing. During the repair, the code must be scanned and stored in the control unit with a suitable diagnostic device via Remote Services. If the code cannot be read, the number combination below the code can be entered manually as an alternative.
The light colour of the LED lamps is also configured as part of this coding.

Replacing lamps and control units: What to look out for?

If a lamp is mechanically damaged and has to be replaced, the front light electronics can be converted from the old to the new lamp. In this case, the LED modules of the new lamp must be adapted to the front light electronics. If the front light electronics are also replaced, they, too, must be adapted to suit in the vehicle. If the lamps and front light electronics are replaced, the control unit must first be accordingly programmed.

Anpassung der LED-ScheinAdaptation of the LED lamps and light control units in the vehiclewerfer und Lichtsteuergeräte im Fahrzeug

The coding of the individual components is performed remotely on the server of the relevant vehicle manufacturer. This customisation can be carried out using macsRemote Services, for example. In order to do this, a macsRemote device is connected to the OBD interface in the vehicle and a connection to macsRemote Services is established. Once the vehicle data and the required service have been selected and confirmed in the application, a ticket can be created and sent. All necessary actions are then coordinated with the workshop in a chat and carried out online by the service technician.

This necessary measure allows the control unit software and coding to be recognised and adapted to suit the vehicle in question. This is the only way to ensure secure communication with other control units in the vehicle. If this adjustment is not carried out, communication and functional errors and the resulting error memory entries cannot be ruled out.

For this reason, the maintenance and repair instructions issued by each individual vehicle manufacturer are to be observed.

Repairing BMW LED lamps in the correct, professional way: Safety and procedure

When replacing electronic components in the lamp, the highest degree of cleanliness has to be maintained. Furthermore, measures regarding protection against electrostatic discharge, ESD for short, are to be observed. Repair work on the lighting system in a vehicle may be carried out exclusively by trained specialists. Repair work that is carried out incorrectly can lead to system failure and to personal injuries. Please observe the repair and safety instructions provided by each individual system producer or vehicle manufacturer!

Description: Precise positioning of the beamsetter is necessary for correct checking and adjustment of the lamps.

Adjusting BMW lamps precisely: Correct adjustment for optimum illumination

The LED lamp must be adjusted if:

Repairs were carried out in which a lamp was removed and then mounted anew.
Repairs or adjustments have been carried out that affect the vehicle height or level.

Before the LED lamps are adjusted, the following test requirements must be met as per vehicle manufacturer:

The vehicle and beamsetter, i.e. headlamp adjustment unit, stand on a level surface.
The vehicle is secured against rolling away.
The tyre pressure corresponds to the vehicle manufacturer's specification.
The lamp cover lenses are clean and damage-free.
The steering wheel is in the "straight-ahead" position.
The correct vehicle level is guaranteed. Vehicles that were previously raised must be lowered to the normal suspension level. The vehicle is moved approx. 15 m on its own axis.
The vehicle load has been checked and, if necessary, adjusted to the load specified by the manufacturer. Not required for vehicles with automatic headlamp levelling!
There are no error entries in the system-relevant comfort control units.

Then the beamsetter (SEG) is to be positioned in the centre, at a distance of 10 cm, in front of the vehicle and aligned to the vehicle using the laser aiming device. In order to do this, open the bonnet, switch on the laser module, define two reference points on the front of the vehicle and align the SEG (beamsetter). Then position the SEG on the lamp in question and align it with the inner LED module. After that, read off the adjustment measurement on the lamp and adjust the SEG accordingly. For the adjustment of lamps, the ignition can now be switched on and the light switch set to the "Low beam/driving lights" position. According to the vehicle manufacturer, because of automatic headlamp levelling, there should be a waiting period of approx. 80 seconds before any adjustment work is started. During this time, movements and vibrations to the vehicle are to be avoided. Then the lamp setting/adjustment is to be checked and corrected if necessary.

A lamp adjustment cannot be made in the "Auto" light switch function.

Adjustment measurement for lamps in BMW vehicles

Lamp adjustment measurement	Model series	Setting value in %
Headlamps	All models	1,0
Headlamps	Exception: E53/E70/E71/E72/E83 F15/F16/F25/F26/F60	1,1
Fog lamps	All models	2,0

In the course of such work, please observe the relevant country regulations (ECE/SAE) and the maintenance and repair instructions provided by the vehicle manufacturer.

The various diagnostic options have been illustrated using as an example the mega macs X diagnostic device and macsRemote Services. The respective test depth and variety of functions can be set out differently depending on the vehicle manufacturer and these are dependent on the relevant system configuration of the control unit.

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