2006-2008 Lexus IS250 & IS350 AWD Control Module: Diagnosis and Replacement Guide

Symptoms of a Failing Transfer Case Control Module

When the AWD control module begins to fail, your vehicle will provide several distinct warnings. The most common sign is the illumination of a warning light on your instrument cluster. You may also notice a change in how the vehicle drives, especially in low-traction situations.

• AWD Warning Light: The most direct symptom is an "AWD" or similar warning light appearing on the dashboard. This indicates the system has detected a fault and has likely been disabled.
• Check Engine Light: A general Check Engine Light may also illuminate, storing diagnostic trouble codes (DTCs) that can be read with an OBD-II scanner.
• Loss of All-Wheel Drive: The vehicle will revert to rear-wheel drive. You may notice a loss of traction when accelerating from a stop on wet or loose surfaces.
• Diagnostic Trouble Codes (DTCs): Specific codes point directly to a module issue. The most common code is U0102, which means "Lost Communication with Transfer Case Control Module". Service manuals for the 2007 IS250 AWD also list codes C1241/94 and U0216/84 as being related to transfer case faults.

Known Issues, TSBs, and Recalls

As of mid-2026, there are no specific recalls or Technical Service Bulletins (TSBs) from Lexus or the NHTSA that directly address the transfer case control module for the 2006-2008 IS250 or IS350.

However, these vehicles were subject to several other important safety recalls, including those for Takata airbags, fuel system leaks, and valve springs. It is recommended to check your vehicle's VIN on the NHTSA website to ensure all applicable recalls have been performed.

Programming and Installation Requirements

This is the most critical consideration when replacing this module. While specific documentation is scarce, Toyota and Lexus electronic modules from this era often require initialization or programming to the vehicle.

Used parts sellers frequently note that programming may be necessary for electronic components to function correctly. The standard procedure for many Lexus modules involves using the dealer-level diagnostic tool, called Toyota Techstream, to sync the new module with the vehicle. While the immobilizer system is not tied to this specific module, failure to program it may result in a persistent AWD warning light and a non-functional system.

It is strongly recommended that you or your mechanic have a plan to program the module after installation. This may require a visit to a Lexus dealership or an independent shop that specializes in Toyota/Lexus electronics and has access to Techstream software.

Buying a Used Transfer Case Control Module: What to Look For

Since new OEM modules are often discontinued and no aftermarket alternatives exist, a used OEM part is the most practical solution. Here’s what to check when buying one:

• Verify the Part Number: The correct OEM part number is 89630-53010. You may also see a manufacturer number, 079500-9161, printed on the unit. Ensure the number on the replacement part matches your original module exactly.
• Inspect for Physical Damage: Check the casing for cracks or signs of being forced open. Pay close attention to the electrical connector pins—they should be straight, clean, and free of any green or white corrosion.
• Look for Water Damage: The module is located in the right-hand (passenger side) rear quarter panel, an area that can be susceptible to moisture from a leaking window seal or trunk gasket. Any sign of water marks, rust, or corrosion on the casing or connectors is a major red flag.
• Source from a Reputable Seller: Purchase from a seller who offers a warranty and a return policy. This gives you protection in case the part is dead on arrival.

Replacement Location and Procedure Overview

The transfer case control module is located inside the vehicle, in the trunk area behind the trim on the right-hand (passenger side) rear quarter panel. Replacement is straightforward for a DIY mechanic with basic tools.

1. Disconnect the Battery: Always disconnect the negative battery terminal before working on any electronic components.
2. Access the Module: Remove the trunk floor covering and the plastic trim panels on the right side of the trunk to expose the module.
3. Unbolt the Module: It is typically held in place by a few 10mm nuts. Remove the nuts and slide the module off its mounting studs.
4. Swap Connectors: Carefully disconnect the electrical connectors from the old module and plug them into the replacement unit.
5. Reassemble: Mount the new module, reinstall the trim panels, and reconnect the battery.
6. Test and Program: After installation, the vehicle will need to be tested. If the AWD light remains on, the module will likely require programming as described above.

Cost Comparison

The cost to fix a faulty AWD module is relatively low, especially when using a recycled OEM part.

Frequently Asked Questions (FAQ)