U011D: Lost Communication With All Wheel Drive Control Module

What it means

A control module has lost communication with the all wheel drive control module. AWD operation may be affected, depending on the vehicle.

How it works

The all wheel drive control module coordinates torque delivery to the vehicle's driven axles. This code sets when another module stops receiving expected messages from that module, so AWD engagement or related control functions may be unavailable.

Common causes

Most likely first.

1. Loss of module power or ground
2. Open, shorted, or damaged communication wiring or connector
3. Module or gateway fault

Symptoms

• AWD warning or message
• AWD functions may be unavailable
• Communication faults in other modules

How to diagnose it

1. Scan all modules for U011D and drivetrain codes, noting which modules cannot communicate with the all wheel drive control module.
2. Review freeze-frame data and warning history for when AWD operation or the communication fault changed.
3. Inspect the AWD module's connectors and harness for water intrusion, corrosion, impact damage, or loose terminals.
4. Check the module's power and ground circuits against the manufacturer's specification.
5. Test its communication wiring for opens, shorts, or poor connections using the vehicle wiring diagram.
6. If the circuits pass, check gateway routing and the AWD module using vehicle-specific diagnostics.

Common fixes

• Repair a damaged or corroded AWD module connector or harness.
• Restore a failed power feed or ground to the all wheel drive control module.
• Repair an open or short in its communication wiring.
• Repair a confirmed gateway fault or replace and configure the AWD module if testing confirms it has failed.

Can I keep driving?

If the AWD warning is on, assume all wheel drive may be unavailable and drive cautiously on low-traction surfaces. Avoid off-road use or conditions that depend on AWD until the system is restored.