Is your GM vehicle acting possessed? You may have a failing Body Control Module.
The Body Control Module, or BCM, is the central command center for your vehicle’s electronic accessories. It manages everything from your power windows and locks to the interior lights, security system, and remote keyless entry. When the BCM starts to fail, it can cause a cascade of confusing and frustrating electrical issues that can be difficult to diagnose.
From the Diagnostic Bay
We had a 2011 Chevy Impala come in that was giving the owner fits. The dome light would randomly turn on while driving, the driver’s side power window worked only when it wanted to, and the key fob was useless. The owner had already replaced the battery and checked all the fuses. After connecting our diagnostic tool, we saw multiple communication errors pointing towards a faulty BCM. A failing BCM can send corrupt data across the vehicle’s network, causing these seemingly unrelated problems. Replacing it with a correctly programmed unit solved every single issue.
Common Symptoms of a Failing GM BCM
- ✔ Power windows, locks, or mirrors operate intermittently or not at all.
- ✔ Interior or exterior lights flicker, stay on, or won’t turn on.
- ✔ “Service Security System” or similar warnings appear on the instrument cluster.
- ✔ The remote key fob stops working or works sporadically.
- ✔ Unexplained battery drain that kills your battery overnight.
- ✔ The engine won’t start or crank due to the anti-theft system (VATS/Passlock) being incorrectly activated.
- ✔ Horn honks unexpectedly or doesn’t work at all.
Why Choose Our Programmed GM Body Control Module?
Don’t waste time and money at the dealership. This replacement Body Control Module is the most efficient solution to restore your vehicle’s functionality. We take the hassle out of the repair by pre-programming the module to your vehicle’s specific Vehicle Identification Number (VIN) before we ship it. This ensures that the BCM communicates perfectly with your car’s other electronic systems right out of the box. Simply provide your VIN after purchase, and we’ll handle the complex software flashing for you.
Important Post-Installation Information
While our programming handles the majority of the setup, some vehicles may require additional steps after installation. These are simple procedures for a qualified technician with a professional scan tool.
- Airbag System Sync: If your airbag warning light is on after installation, a procedure called “Setup SDM Primary Key in BCM” is needed to sync the new BCM with the airbag system. This is only required if the light appears.
- Brake Pedal Position Relearn: On certain models, a brake pedal position sensor recalibration might be necessary to ensure your brake lights and traction control system function correctly.
Please note: Specific procedures can vary by vehicle. Always consult a factory service manual or a qualified technician for guidance.
Frequently Asked Questions
What is a BCM and what does it do?
The Body Control Module (BCM) is a computer in your car that controls and monitors various electronic body functions, such as power windows, locks, lights, wipers, and the security system.
How do I know if my BCM is the problem?
Common signs include multiple, unrelated electrical issues like flickering lights, malfunctioning power accessories, security system warnings, and intermittent no-start conditions. A professional diagnosis is the best way to confirm a faulty BCM.
Why do you need my VIN?
Your VIN (Vehicle Identification Number) allows us to program the BCM with the exact software and vehicle-specific options for your car. This ensures proper communication and functionality, making the installation process much smoother.
Is this part difficult to install?
The physical replacement is typically straightforward, involving unplugging the old module and plugging in the new one. However, some vehicles may require post-installation procedures like an airbag sync or brake sensor relearn, which require a professional scan tool.
What if my airbag light comes on after installation?
This indicates that the BCM needs to be synced with the airbag system’s computer (SDM). A technician will need to perform the “Setup SDM Primary Key in BCM” procedure with a compatible diagnostic tool to resolve this.
Do I need to return my old BCM?
No. There is no core charge for this part. You can keep your original module.