2020-2025 Audi A3, S3, RS3 & Q4 e-tron LED Headlight Module: Failures, Recalls, and Programming

Symptoms of a Failing LED Headlight Control Module

When an LED headlight control module begins to fail, it can cause a range of issues from annoying to dangerous. Because the module controls power and logic, symptoms are almost always electrical in nature.

• One Headlight is Out: The most common symptom is one headlight not working at all, while the other functions perfectly. This often points to a module failure for that specific side.
• Flickering or Dimming Headlights: You may notice one or both headlights flickering, pulsing, or appearing dimmer than usual. This can happen intermittently and may be more noticeable when the engine is under load.
• Dashboard Warning Lights: A failure will often trigger a yellow warning message on the dashboard, such as "Headlight range control defective" or a 🎬 Watch: Understanding the headlight range control fault warning general headlight fault symbol. This indicates the system has detected a problem with the automatic leveling or adaptive functions.
• Turn Signal or DRL Malfunction: Since the module controls multiple lighting functions, you might experience issues with the turn signal or daytime running light on the affected side.
• Headlights Stuck in One Position: The adaptive or auto-leveling feature may stop working, causing the headlights to be stuck pointing too high or too low.
🎬 See how to fix a headlight range control sensor

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

While widespread failures of this specific module on the A3/S3/RS3 are not heavily documented, the related Q4 e-tron models have a notable recall that owners should be aware of.

Recall 941L: Incorrect Headlight Software on Q4 e-tron

Audi issued a compliance recall (NHTSA ID: 24V361, Audi Code: 941L) for certain 2022-2024 Audi Q4 e-tron and Q4 e-tron Sportback models. The issue is that the headlight control modules were programmed with European-market software that does not comply with North American safety standards (FMVSS 108). This software can cause the parking light to behave incorrectly when the turn signal is active, potentially reducing the vehicle's visibility to others and increasing the risk of a crash. The fix involves a simple software update performed by an Audi dealer, free of charge. No hardware or parts are replaced for this recall.

Variant Differences: Standard LED vs. Matrix-Design LED

These Audi models were available with two main types of headlights, and it is critical to understand which your vehicle has before purchasing a control module.

• Standard LED Headlights: These are the base headlights. They provide excellent illumination but do not have advanced adaptive capabilities. They use different control modules.
• Matrix-Design LED Headlights: This is an optional upgrade that uses a sophisticated array of individual LEDs. These headlights can selectively dim portions of the high beam to avoid dazzling other drivers while illuminating the rest of the road. This specific control module, part numbers 4K0941592BE and 4K0941592BL, is for vehicles equipped with these Matrix-design headlights.

Buying a Used LED Headlight Control Module: What to Look For

Purchasing a used OEM module can be a cost-effective solution, but careful inspection is key. Aftermarket modules are generally not recommended for this part, as they often cannot be programmed correctly to the vehicle and may lack the quality control of an OEM part.

1. Verify the Part Number: Check the number on your original module. The most common part numbers for this application are 4K0941592BE and 4K0941592BL. Other compatible numbers may exist, such as 4K0941592BG which supersedes 4K0941592BC. Always match the part number exactly or confirm supersession with a reliable source.
2. Inspect for Physical Damage: Look for cracks in the plastic housing or damage to the electrical connector pins. The module is often located on the bottom of the headlight assembly, making it vulnerable to moisture.
3. Check for Corrosion: Examine the pins and the housing for any signs of water intrusion or corrosion. A module with any corrosion should be avoided, as it indicates internal damage.
4. Understand the Programming Requirement: Be aware that a used module cannot be simply swapped in. It will require professional programming to work in your vehicle. Factor this additional cost into your budget.

Replacement and Programming Guide

Physically replacing the module is moderately difficult, but programming it requires specialized tools and knowledge.

Accessing and Replacing the Module

The control module is typically bolted to the underside or back of the headlight assembly. Access varies by model:

• On the Audi A3 (8Y), accessing the module often requires removing the front bumper and then unbolting the entire headlight assembly to reach the module. 🎬 Watch: Step-by-step Audi headlight removal tutorial While some guides for older models suggest access through the wheel well, the 8Y generation is more complex.
• The procedure for the Q4 e-tron is similar, generally requiring bumper removal for full access to the headlight housing screws.

Once the headlight assembly is removed from the vehicle, the module is typically held on by a few Torx screws. The swap itself is straightforward: unplug the electrical connectors, unscrew the old module, and bolt the new one in its place.

The Critical Programming Step: Component Protection

Modern Audi vehicles use a security system called Component Protection (CP). This system links major electronic modules, like this one, to the car's unique Vehicle Identification Number (VIN). When you install a different module, the car detects a mismatch and puts the component into a limited-functionality mode. For a headlight module, this can mean the light stays dim, flickers, or won't turn on at all.

Removing Component Protection requires a tool called ODIS (Offboard Diagnostic Information System) which has a live online connection to Audi's servers in Germany. This procedure, sometimes called "online adaptation" or "parameterization," pairs the new module to your car. This service can only be performed by:

• An authorized Audi dealership.
• A qualified independent European auto repair shop that subscribes to the ODIS service.

Standard diagnostic tools like VCDS or OBDeleven cannot remove Component Protection.

Cost Comparison

Frequently Asked Questions (FAQ)