2022-2024 Subaru WRX Headlight Control Module: SRH Failures and Programming Guide

Compatibility: This Module is Not For All WRX Models

Attempting to install this module on a Base or Premium model will not add the adaptive feature, as the vehicle lacks the specific headlight assemblies, wiring, and sensors required for it to operate.

Symptoms of a Failing Headlight Control Module

When the headlight control module begins to fail, you will likely see clear warning messages on your dashboard. The car's computer is good at detecting problems within this system. Here are the most common signs:

• "SRH OFF" Warning Light: The most common symptom is a yellow or amber warning light on the instrument cluster that says "SRH OFF" or shows a symbol of a headlight with an arrow and the word "OFF". This indicates the Steering Responsive Headlight system has been disabled due to a fault.
• Headlights Don't "Dance" on Startup: When you start a WRX with SRH, the headlights should perform a quick calibration sequence, moving side-to-side and up-and-down. If you notice they no longer do this, it points to a problem in the system.
• Adaptive Function Stops Working: The headlights will no longer turn with the steering wheel while driving on curves. The effect is subtle, but its absence can be noticeable on dark, winding roads.
• Headlights Stuck in One Position: In some cases, a failure could cause the headlights to be aimed incorrectly, either too low, too high, or off to one side.
• One or Both Headlights Inoperative: While less common, a severe internal failure of the module could potentially cut power to the headlight assembly, causing a headlight to go out completely.
• Associated OBD-II Codes: A professional scan tool that can read body control module codes may find specific trouble codes. A known code for a similar system on the Subaru BRZ is B2919 (Auto Headlamp Leveling Sensor Signal), which can be triggered by a faulty module.

Known Issues, TSBs, and Recalls

As of this writing, there are no specific recalls or widespread, documented failures for the headlight control module on the 2022-2024 WRX. However, there are related items to be aware of:

• Subaru TSB 07-206-22R: While issued for the 2022 BRZ, this Technical Service Bulletin is highly relevant. It addresses an issue where the auto headlight beam leveler control module could inaccurately store a DTC B2919 fault code. The fix is to replace the module with an updated part and perform an initialization procedure. This confirms that module-related issues are known and that replacement requires a special procedure.
• Moisture Intrusion: On many vehicles from all manufacturers, the most common killer of headlight control modules is water. These modules are typically mounted on the bottom of the headlight assembly. If the headlight housing develops a bad seal and allows condensation or water to get inside, it can drip directly onto the module, causing corrosion and short circuits.

Programming and Installation Requirements

After installation, a diagnostic tool like the Subaru Select Monitor (SSM) used by dealerships is required to perform the "Auto Headlight Beam Leveler Initialization." This procedure teaches the new module its proper position and allows it to communicate with the vehicle's other computers. Failure to perform this step will likely result in the SRH system remaining disabled and the warning light staying on. While some high-end independent shops may have tools capable of this function, a visit to a Subaru dealer or a specialist is often required.

Buying a Used Headlight Control Module

A used OEM module is an excellent, cost-effective alternative to a brand-new part, as there are no aftermarket options available for this component. Since it's an electronic part with no moving pieces, a used module from a reputable source is just as reliable as a new one, provided you perform a careful inspection.

What to Inspect:

• Check for Corrosion: The electrical connector pins are the most critical area. Look for any white, green, or chalky residue on the pins or inside the connector housing. Any sign of corrosion means the part was exposed to moisture and should be rejected.
• Examine the Casing: Look for cracks, deep scratches, or any sign that the plastic casing has been pried open. The module should be perfectly sealed.
• Verify the Part Number: Make sure the part you are buying is stamped with 84051VC020. While other numbers may look similar, they may be for different vehicles or systems.
• Mounting Points: Ensure all plastic mounting tabs are intact and not cracked or broken. These are needed to secure the module firmly to the headlight housing.

Cost Comparison

Prices can vary by supplier and location. The following is an estimated cost breakdown to help you understand the value of a used OEM part.

Frequently Asked Questions (FAQ)