BMW FRM module
If you've ever faced the situation where your BMW car's headlights stay on or the turn signal doesn't work, the likely cause may be a faulty FRM.In these lines, we'll learn about the problems with the FRM module in your BMW. We'll talk about the FRM, its application, the functions it performs, and the problems it creates when it's faulty.
What is the FRM module?
The FRM is an electrical control unit designed to control light and window functions. The module receives signals from several sensors in the car and controls several aspects of the vehicle based on them. The FRM is the reason your DRL works during the day or your parking light comes on every time you park. The FRM is what also controls the power windows, outside mirrors, adaptive headlights and several other functions.That's why if it's not working properly, it can create several problems at once, but because they're common, they're easy to recognize. FRM is also known as Footwell mode because of its positioning in the driver's area.
Functions controlled by FRM modules
The FRM module receives signals from several sensors installed on the car, based on which it controls lights and windows and performs other system functions. Most of these sensors are common to all BMWs.
Common sensors are:
Height sensors-
Circuit breaker-
Reversing light switch-
Brake light switch-
Flashing hazard warning switch-
Driver's door switch block-
Door contacts - for front doors-
Locking the door on the driver's side
Using feedback from these sensors, the FRM controls the following mechanisms: Exterior lights- Headlamps- Stop lights- Light- Fog light- Parking light- License plate light- Direction indicators- Hazard warning lights- High centre mounted stop light- Adaptive headlamps by coordinating 2-motor controllers Interior lights- Interior dashboard lights- Front courtesy light- Rear courtesy light- Trunk light- Glovebox light- Footwell light
Functions of the FRM module:
In addition to the standard lighting function, the FRM also performs several system functions. Such functions are:
1. Establishing the gateway between LIN Bus and K+Can The FRM module in the BMW establishes communication between the LIN bus and the CAN. Using this connection, the FRM transfers relevant messages to the various destination buses.Components on the LIN Bus: - Special equipment exterior mirrors- Driver's door switch block- x2 band power controllers
2. Activation via different signals By using different signals, the FRM module can be activated. Such signals are: - K-CAN active- Hazard warning switch is ON- Vehicle alarm system has been triggered- Terminal-15 ON- Door contact status has changed
3. Storing the vehicle order
The FRM is able to store the car's command, which is what allows the vehicle to be identified. It also stores all important vehicle equipment characteristics. To store the command in the FRM, the vehicle must be travelling at 5 km/h or less with terminal-15 ON.
Other system functions: -
Exterior mirrors- Electric drive window- Central locking system- 2 belt feeder controller (E92 only)
FRM control units
To control different lighting functions, the FRM uses various control units. Below is a list of all these control units: Exterior light control units - DSC: Dynamic Stability Control- DSC: Long Phase Assist FLA- LDM: Longitudinal Dynamics Management- RLS: Rain/Light Sensor- RLSS: Solar Rain/Light Sensor
Interior light control units - ACSM or MRS: Advance Crash Safety Module/ Multiple Restraint System- FZD: Roof Function Centre- JBE: Junction Box Electronics- SZL: Steering Column Switch Cluster
Other control unit- Seat belt extension controller (E92 only)
FRM issues:
First of all it is good to know that FRM modules are sensitive devices. They are fixed tightly to the footwell on the driver's side. It's out of contact, and to get to it you'll have to undo a few screws. Because of the sensitivity , a little water ingress or voltage fluctuation can damage these devices. Often, starting the machine or replacing the battery can damage your FRM.This can cause several problems simultaneously. Below is a list of such problems caused by a malfunctioning FRM module:
- Faulty headlights-
Indicators don't work-
No interior lights-
No long phase-
Electric windows don't work-
Dashboard service light is always on-
Climate control failed-
Rear lights do not turn on/off-
No automatic folding mirrors
In the case of a defective FRM, it is always better to send it in for repair. You can also buy a new one, but it will add a lot of expense.A new FRM module costs between 400 and 500 Euro. Then you'll have to program it to your vehicle's specifications, which adds extra cost. The warranty for these devices is also short, given the sensitivity.Simply put, a new FRM module will cost at least 4x the cost of repair.
FRM module error codes
A faulty FRM cannot communicate with OBD-2 scanners, so running a diagnostic is unlikely. However, you can find fault codes in other control modules to make sure the FRM is faulty. During diagnostics you may get any of the following common fault codes:
- 497F - Message error (status, reverse gear, 0x3B0) Transmitter for diesel electronic receiver module - A3B4 - Message (lighting condition) incorrect, FRM transmitter permanent- A3C1 - Message (FRM foot space module) Incorrect COMBI receiver, FRM transmitter - Permanent- E72B - Window error- E72C - Window error
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