Symptoms of a bad Body Control Module

Symptoms Of A Bad Body Control Module

The ability of modern cars to function properly depends on an advanced communication network. A variety of terminals, wires, and sensors are found in this network, and they all provide feedback to various electronic computer modules. The majority of the time, each of a car’s critical systems has a computer module that controls.

The BCM, or body control module, is one such module that is present in almost all modern cars. This module is responsible for several safety and comfort-related functions that are of great value to the driver and other occupants of a vehicle. But what happens when this component goes bad?


Symptoms Of A Bad Body Control Module?

Symptoms of a bad Body Control Module

Battery Drain Quickly

Repeated, excessive battery drainage, often known as a parasitic draw, is one of the symptoms of body control module failure that is often experienced. While some parasitic draw is acceptable, excessive draw made possible by a BCM failure can quickly drain a battery. This draw happens when a BCM keeps providing power to a certain accessory at the wrong times.

Erratic Electrical Function

The horn, lights, and wipers of a car can all operate periodically if the body control module is faulty. Unusual door lock and radio operation are additional symptoms of body control module failure, as are dials in the instrument cluster that sweep erratically. When more than one of these symptoms is present at any particular period, the probability that such problems are BCM-related rises.

Related: Symptoms of bad ECM (Engine Control Module)

Check Engine Light

The instrument cluster of a car could be impacted greatly by a malfunctioning body control module. Unremarkable dash displays might suddenly become extremely lit, almost like a Christmas tree. This happens when one or more of a vehicle’s extra control modules, such as the airbag control module, powertrain control module, or transmission control module, are unable to interact with a BCM.

Car Won’t Start

In certain instances, a damaged or faulty body control module may also make it impossible for a vehicle to start at all. Even though it happens rarely, a bad BCM can inhibit starter engagement by failing to recognize the transponder chip in the key or by simply failing to provide a “start” signal from the ignition switch. The inability of the BCM to communicate with other connected control modules can also cause problems starting the engine.


To ensure the proper functioning of a vehicle’s electronic systems, it is important to be able to identify the symptoms of a damaged Body Control Module (BCM). Paying close attention to these symptoms as soon as they appear can help prevent potential electrical and operational issues, and maintain the vehicle’s reliability and overall performance.


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