Bimmerscan

BMW Footwell Module (FRM)

BMW Footwell Module

BMW Footwell Module

The footwell module (FRM) is an electrical nodal point in the footwell on the drivers side. The footwell module picks up the signals from the doors and controls the lighting. The footwell module also controls the adaptive headlights. The footwell module is also the interface to the dashboard.

The following components deliver signals for the footwell module:

  • Height sensors
  • Reversing light switch
  • Brake light switch
  • Hazard warning flasher switch
  • Light switch
  • Driver’s door switch block
  • Door contacts in front doors
  • Driver’s door lock

A number of control units are involved in the lighting system. In a stricter sense, the following control units are involved in the lighting (in alphabetical order):






ACSM or MRS: Crash safety module / multiple restraint system

  • E81, E82, E87, E89, E90, E91, E92: multiple restraint system
  • E70, E71, E93: ACSM stands for ”Advanced Crash Safety Module”, also known as the Crash Safety Module

The footwell module is connected to the crash safety module / MRS control unit via the K-CAN. In the event of an accident with corresponding severity, the footwell module switches on the interior light and the hazard warning lights automatically.

  • E92
  • The crash safety module sends a message regarding the front passenger seat occupation detection on the K- CAN. The belt handover on the passengers side is only activated when the front passenger seat is occupied.

AHM: Trailer module

The trailer module delivers the signal indicating whether a trailer is attached to the vehicle. The trailer module also controls the trailer lighting. During trailer towing, the trailer module automatically disables e.g. the rear Park Distance Control (PDC) and the rear fog lamp on the vehicle.

If a trailer is detected, the automatic parking function is disabled. Automatic parking function: To improve the view of the kerb, the outside mirror glass is folded downwards when reverse gear is engaged. This brings the lower area immediately around the vehicle, i.e. the kerb, into the field of vision.

The trailer module (AHM) is connected to the footwell module via the K-CAN.

DSC: Dynamic Stability Control

When cruise control is in operation, the brake lights are actuated during automatic braking (legal requirement). To do this, a signal must be sent from the DSC to the accelerator pedal module via the PT-CAN.

DSC: FLA: High-beam assistant

In accordance with the traffic situation, the high-beam assistant sends a switch-on recommendation or a switch-off recommendation for the high-beam headlights to the footwell module (FRM). On the basis of this recommendation and various other the input variables, the footwell module decides whether the main-beam headlights should be switched on or off.

FRM: Footwell module

The footwell module is connected to the vehicle with 3 plug connections. Two 51-pin connector connect the main wiring harness. Another 26-pin connector is for the connection to the dashboard.

FZD: Roof function center

The roof function centre is responsible for the components of the interior lighting in the roof area. The Basic variant of the roof function centre has its own control unit. The interior light and the rear-compartment interior light are activated via the footwell module (FRM).
The High variant of the roof function centre has its own control unit, the FZD control unit.
The footwell module is connected to the FZD control unit via the K-CAN.

JBE: Junction Box Electronics

The lighting for the luggage compartment and the glove box lighting are connected to the junction box electronics.

LDM: Longitudinal dynamics management

In conjunction with the LDM, the option ”Active Cruise Control” uses the ”turn signal” from the footwell module to help when changing lanes. In other words, if a left turn indicator is given before overtaking, the distance to the vehicle in front is reduced. The vehicle to be overtaken is then ”lost” more quickly. On the other hand, when changing to the right-hand driving lane, a vehicle moving there is picked up more quickly.

RLS / RLSS: Rain/light sensor or rain/light solar sensor
> E81, E82, E87, E89, E90, E91, E92, E93: Rain/light sensor
> E70, E71: rain/light solar sensor

The rain/light sensor measures the ambient brightness outside the vehicle. Depending on the ambient lighting conditions, the footwell module will switch the driving lights on or off. To do this, the automatic driving lights control must be activated (light switch in switch position ”A”).

At dusk, the rain-light sensor sends the message ”dusk”. The footwell module switches the low-beam headlight on. The automatic headlight-range adjustment for the dipped-beam headlights is actuated. In darkness, the rain/light sensor transmits the message ”Darkness”. The adaptive headlights are then activated when the vehicle is cornering.

SZL: Steering column switch cluster

The switch signals from the turn-signal/high-beam switch are picked up and evaluated by the SZL. The evaluated switch signals are forwarded as resistance-coded by the SZL via direct lines to the footwell module.

The following components are controlled:

  • Exterior mirrors
  • Power window drive
  • Headlight
  • Tail lights
  • Fog lights
  • Centre high-mount stop lamp
  • Auxiliary turn indicator light
  • Front courtesy lighting
  • Rear courtesy lighting
  • Number-plate light
  • 2 stepper motor controllers for the adaptive headlight stepper motors
  • 2 belt feeder controllers (only E92)

Seatbelt extender controller (only E92)

The footwell module (FRM) activates the two belt hand-over controllers for the drivers and passengers side. The belt hand-over controllers are connected across an LIN bus on the footwell module. The belt hand-over controller activates the drive of the belt hand-over. The position of the drive is reported back to the belt feeder controller by a Hall sensor in the drive. The end position of the extended belt feeder is recorded by another Hall sensor. The end position is indicated to the belt feeder controller. The belt feeder controller transmits both signals to the footwell module (FRM) via the LIN bus. The actuation circuit is located in the footwell module. The belt handover on the passengers side is only activated when the front passenger seat is occupied.

System Functions
The following functions are executed by the footwell module:
– Gateway between LIN bus and K-CAN
– Waking by means of various signals
– Storing vehicle order
Gateway between LIN bus and K-CAN
The footwell module (FRM) enables communication to take place between the LIN bus and the K-CAN. The footwell module transfers the messages to the relevant recipient bus. Components on the LIN bus: Special equipment exterior mirrors Switch block in driver’s door, High variant 2 stepper motor controllers for the adaptive headlight stepper motors 2 belt feeder controllers (only E92)
Waking by means of various signals
The footwell module (FRM) can be wakened via the following signals: K-CAN active, Terminal 15, ON Hazard-warning switch, ON Change in status of door contacts, Anti-theft alarm system triggered.

Footwell modules variants:

LOW == without fog lamps, without XENON, without AHL
NSW, BASIS == with fog lamps, without XENON, without AHL
XE == with fog lamps, with XENON, without AHL
AHL == with fog lamps, with XENON, with AHL

Dealing with short circuits in the footwell module

Note:
Dealing with short circuits in the footwell module depends on the production date of the footwell module. Differences result for the production date 09/2007 and 09/2009.

Description of dealing with short circuits up to 09/2007:
If a short circuit is detected in a circuit, the circuit is switched off after one minute. This circuit remains switched off until there has been a terminal change (terminal 15 > terminal 30 ‐> terminal 15). A renewed attempt to switch on is only made after a terminal change. After a total of 50 terminal changes have occurred in a vehicle while the circuit had a short circuit, the corresponding output from the footwell module will be switched off permanently . This is the case if the fault entry can no longer be deleted even though the short circuit has been repaired. Exception: xenon bulbs: If the short circuit was present in the circuit of a xenon bulb, the output will be switched off permanently after 20 terminal changes. In this case, the footwell module must be replaced.

Description of dealing with short circuits as of 09/2007:
If a short circuit is detected in a circuit, the circuit is switched off after one minute. This circuit remains switched off until there has been a terminal change (terminal 15 > terminal 30 ‐> terminal 15). A renewed attempt to switch on is only made after a terminal change. The control unit permanently switches off the corresponding output if a total of 10 terminal changes have taken place while there is a short circuit in a circuit. After repairing the short circuit, the output is reactivated using a diagnosis command in the testing procedure. If the short circuit is still present, the output will be switched off again after 1 minute and permanently switched off again after another 10 terminal changes.

Exception: xenon bulbs: If the short circuit is still present in the circuit of a xenon bulb, the output will be switched off again after 1 minute and permanently switched off again after another 4 terminal changes. An output can be reactivated 5 times by a diagnosis command in the testing procedure. The footwell module permanently switches off the corresponding output if a total of 60 terminal changes have taken place while there is a short circuit in the circuit. Exception: xenon lamps: A xenon output can be reactivated 5 times by a diagnosis command in the testing procedure. The footwell module permanently switches off the corresponding output if a total of 24 terminal changes have taken place while there is a short circuit in the circuit. The output cannot be reactivated, even with the diagnostic command, and the fault entry can no longer be deleted. In this case, the footwell module must be replaced.

Description of dealing with short circuits as of 09/2009:
If a short circuit is detected in a circuit, the circuit is switched off after ten seconds. This circuit remains switched off until there has been a terminal change (terminal 15 > terminal 30 ‐> terminal 15). A renewed attempt to switch on is only made after a terminal change. The control unit permanently switches off the corresponding output if a total of 10 terminal changes have taken place while there is a short circuit in a circuit. After repairing the short circuit, the output is reactivated using a diagnosis command in the testing procedure. If the short circuit is still present, the output will be switched off again after 10 seconds and permanently switched off again after another 10 terminal changes. Exception: xenon bulbs: If the short circuit is still present in the circuit of a xenon bulb, the output will be switched off again after 10 seconds and permanently switched off again after another 4 terminal changes.

An output can be reactivated 5 times by a diagnosis command in the testing procedure. The footwell module permanently switches off the corresponding output if a total of 60 terminal changes have taken place while there is a short circuit in the circuit. Exception: xenon lamps: A xenon output can be reactivated 5 times by a diagnosis command in the testing procedure. The footwell module permanently switches off the corresponding output if a total of 24 terminal changes have taken place while there is a short circuit in the circuit. The output cannot be reactivated, even with the diagnostic command, and the fault entry can no longer be deleted. In this case, the footwell module must be replaced.

The short circuit counter can be reset using ISTA-D which is pretty straight forward or using Tool32. The procedure for resetting the short circuit counter using Tool32 is shown below.

Resetting the Short Circuit Counter via Tool32

Warning: Check your wiring harnesses and verify there are no shorts present BEFORE resetting!

Connect to car and open Tool32

Load the SGBD group file, for FRM1, use FRM_87.prg, for FRM2 or FRM3, use FRM_70.prg

Navigate to the window labeled “Tabellen-Info.” In the drop down menu, select “LAMPNRTEXTE[x][xx].” [x][xx]. This table will list the lamp fixtures and their corresponding IDs. These IDs are the arguments you need to enter to execute your job. Note the lamp ID for the circuit that is out.

Once you have your lamp ID ready, you can select the “Select Job:FRM_XX” window and on the left side, you will see the available jobs for your control unit. Scroll down and select the job “_reset_kurzschluss_sperre”.

Now enter your lamp ID or “argument” into the field. The checkbox for “Data” does NOT need to be checked off. If the job does not execute properly, you can try ticking this box.

Press F5 to run the job. After you have received an “OKAY” response, you can close Tool32 and use INPA or whatever program/method you use to clear any remaining faults.

SI B01 20 16
BMW FOOTWELL MODULE: LIMITED WARRANTY EXTENSION TO 8 YEARS/125,000 MILES

SI B 01 20 16_Footwell

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