5 Symptoms of a Bad Body Control Module
Today’s vehicles rely on a complex network of connectors, cables, and sensors that power electronic modules that control vital systems. One such module is the Body Control Module (BCM), which is the control center for a wide variety of comfort and safety features.
Though rare, your vehicle’s body control module can experience serious functionality issues, including complete failure. Here are the most common symptoms of a failing BCM and how much it might cost to replace one:
What is a Body Control Unit? The body control module is an electronic driver designed to monitor and control various body-related functions of a vehicle.
The exact functions that a vehicle’s body control module monitors vary depending on the vehicle model. However, in most cases, a vehicle’s body control module supports the wipers, lights, heating, air conditioning, and anti-theft functions.
The body control module is also responsible for communicating with the vehicle’s various other control modules. This communication allows for further optimization of the integration of the vehicle’s vital systems, resulting in a more efficient, trouble-free driving experience.
Where is the Body Control Unit?
In most vehicles, the Body Control Unit is located under the dashboard. This is usually a pretty standard location, as most modules of this type are located in close proximity to this area. However, the exact side (driver/passenger) that the Body Control Module is located on will vary depending on the vehicle model.
In some cases, accessing the Body Control Module may require partial disassembly of the dashboard and surrounding panels themselves. Fortunately, this can be done with minimal effort, as many dashboard components are assembled using only push-fit clamps.
Symptoms of Body Control Module Failure
There are many signs of a body control module failure. However, some of these symptoms are more common than others, but it is important to understand each of them in case you experience this type of error in the future.
#1 – Repeated Battery Discharge
One of the most common symptoms of a body control module failure is repeated excessive battery discharge, also known as parasitic discharge. While some parasitic discharge is acceptable, excessive discharge caused by a faulty BCM can drain the battery in a matter of hours. This discharge occurs when the BCM continues to power certain accessories at the wrong times.
#2 – Abnormal Electrical Functions
A faulty body control module can cause various electrical functions to work intermittently, such as: B. Car horn, lights, electric windows, mirrors, and windshield wipers.
Violent vibration of the instrument panel is also a clear sign of a body control module failure, as are erratic door locks and radio operation. If more than one of these symptoms are present at the same time, it is highly likely that such an issue is related to the BCM.
#3 – Security System Issues
Most of the time, your vehicle’s security system is controlled by the body control module. Therefore, it’s easy to assume that consistent, yet inexplicable issues related to your vehicle’s safety systems are the by-product of a faulty or defective body control module. This could even include issues with your vehicle’s keyless or passive entry features.
#4 – Dashboard Warning Lights
A faulty body control unit can damage your vehicle’s instrument cluster. An otherwise nondescript dashboard display may suddenly light up and look like a Christmas tree. This occurs when the BCM cannot communicate with another additional control module in the vehicle, such as the transmission control module, powertrain control module, or airbag control module.
#5 – Difficulty Starting
A malfunction or defect in the body control module (and sometimes the ignition control module) can sometimes prevent the vehicle from starting at all.
Though rare, a defective BCM can cause the starter to not engage by failing to identify the transponder chip in the key or failing to send a “start” signal from the vehicle’s ignition switch.
Lack of communication between the BCM and other corresponding control modules can also lead to starting difficulties.
Can I drive with a defective BCM?
This is due to the unpredictable nature of when computer modules are about to fail.
There is simply no way to predict which functions of a broken computer will work as intended at any given time. The problem is that you cannot determine if a faulty BCM is causing a safety-related problem.
There is no guarantee that a defective BCM will cause your vehicle’s lights to turn on as expected, even if it hasn’t caused such problems in the past. This poses a serious danger to vehicle occupants.