2021-2025 Ford Bronco Audio Control Module: Failures, Programming, and Replacement Guide

Is it the Audio Control Module (ACM) or the SYNC APIM?

Before diagnosing a problem, it's important to understand the two main parts of your Bronco's infotainment system. The APIM (Accessory Protocol Interface Module) is the brain that runs the SYNC touchscreen, navigation, Apple CarPlay, Android Auto, and Bluetooth connections. The ACM (Audio Control Module) is the component that actually receives radio signals and creates the sound that goes to your speakers. If your screen is frozen or apps won't connect, the APIM is the likely culprit. If your screen works but you have no sound, popping noises, or audio cutouts, the ACM is the part to investigate.

Symptoms of a Failing 2021-2025 Bronco ACM

A faulty Audio Control Module can cause a range of frustrating issues. Here are the most common signs reported by owners:

• No Sound From Speakers: The most frequent symptom is a complete loss of audio from all sources, even though the radio display appears to be on and functioning.
• Intermittent Audio Cutouts: Sound may randomly cut out and come back without warning. This can happen across all inputs, including radio, CarPlay, and even parking sensor alerts.
• Loud Popping or Static: A sudden, loud pop from the speakers, often at startup, followed by silence or persistent static and crackling noises.
• Radio Will Not Power On: The entire audio system may be completely dead and unresponsive.
• Unresponsive Controls: The volume knob or source selection buttons may stop working, even if the touchscreen controls appear to respond.
• Warning Chimes from Instrument Cluster: When the ACM fails, the vehicle may reroute critical warning chimes (like the seatbelt reminder) through a small speaker in the instrument cluster instead of the main audio system.

Known Issues, TSBs, and Recalls

While there are no major recalls for the ACM itself, there are several known issues and Technical Service Bulletins (TSBs) you should be aware of.

Software Issue on 2025 Models (7-Speaker System)

Some 2025 Bronco models with the standard 7-speaker audio system may experience intermittent audio loss. This is often accompanied by Diagnostic Trouble Codes (DTCs) like B128A:01, B128A:11, B128A:12, and others. According to forum discussions referencing dealer information, this is a known software bug. Important: Replacing the ACM hardware will not fix this specific issue. Ford is reportedly working on a software update to correct this condition.

Audio Cutouts on B&O Systems (A2B Bus Errors)

Owners of Broncos with the premium B&O sound system have reported audio cutouts linked to communication errors on the A2B (Automotive Audio Bus). This digital connection links the ACM to the B&O amplifier/DSP. Diagnostic scans may show codes like B150C:55, B150C:87, or B150C:8F, indicating a communication problem. This could be a software issue, a loose connection, or a fault in the wiring between the modules.

TSB for Subwoofer Rattle

Ford has issued TSBs 23-2241 and 24-2387 for a rattle that can come from the rear cargo area trim panel on Broncos equipped with a factory subwoofer. This is caused by trim fasteners, not a faulty ACM, and can be fixed by a dealer by replacing the clips.

Programming and Calibration: The Most Important Step

You cannot simply swap an Audio Control Module in a modern Ford Bronco. The new or used module must be programmed to your vehicle's specific configuration.

This process, known as Programmable Module Installation (PMI), downloads the vehicle's unique "As-Built" data into the ACM. This data tells the module about the vehicle's VIN, what sound system it has (base or B&O), the number of speakers, and other specific features. Without correct programming, the module will not work.

Who Can Program a Bronco ACM?

• Ford Dealership: A dealer has the official Ford diagnostic tools (IDS/FDRS) and guaranteed access to the correct software to perform the programming.
• Independent Repair Shops: Many independent shops that specialize in Ford vehicles invest in the same diagnostic software and can perform the programming.
• Advanced DIY with FORScan: Enthusiasts with technical expertise can use a third-party tool called FORScan with a compatible OBD-II adapter to program the module themselves. This is a powerful tool but can cause serious issues if used incorrectly. It requires saving the As-Built data from your old module (if possible) and writing it to the new one.

Buying a Used 2021-2025 Bronco Audio Control Panel

Buying a used OEM module is an excellent way to save money, as aftermarket options are generally unavailable for this complex part. However, you must be careful to get the right one.

1. Match the Engineering Part Number: The most critical step is to match the engineering ID on the sticker of your original part. The most common number is M2DT-18K811-AB3JA6. While service numbers like M2DZ-18C858-AA exist, the engineering number on the unit itself is the best guarantee of compatibility.
2. Inspect for Damage: Check the connectors for any signs of corrosion, bent pins, or water intrusion. Inspect the case for cracks or other physical damage.
3. Get the Donor VIN: Whenever possible, purchase from a seller who can provide the Vehicle Identification Number (VIN) of the Bronco the part came from. This can be a lifesaver if you need to look up the original "As-Built" data to program the module using FORScan.
4. Consider a Repair Service: As mentioned above, repairing your original unit is often the simplest path. It costs more than a typical used part but eliminates all programming headaches and compatibility risks.

Replacement Cost Comparison

The cost to replace a Bronco ACM can vary significantly based on the part source and labor for programming.

Frequently Asked Questions (FAQ)