Lost Communication with AWD Module
Diagnostic trouble code U011D indicates that the powertrain control module (PCM) or another critical module has lost communication with the all-wheel drive (AWD) control module over the controller area network (CAN) bus. This occurs when the AWD module fails to transmit expected messages within a predetermined time. The loss of communication prevents the drivetrain management system from coordinating torque distribution to the wheels, impairing AWD system operation.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- AWD control module damaged or not receiving power
- CAN bus wiring issues (short circuit or open circuit)
- Poor connection or corrosion at AWD module connectors
- Blown fuse or relay in the AWD module power circuit
- Faulty ground connection for the AWD module
- Problem with the powertrain control module (PCM)
3. Symptoms You Will Notice
- AWD system inoperative or warning light on
- Reduced traction or stability in slippery conditions
4. Step-by-Step Diagnosis
Check for blown fuses and relays in the AWD module circuit
Inspect CAN bus wiring and connectors for damage or corrosion
Verify power and ground at the AWD module connector
Test AWD module communication using a scan tool
If necessary, check PCM for faults or update software
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended, as the AWD system may be inoperative, reducing traction and stability, especially in adverse conditions. Have the issue diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $100 to $1,200, depending on the root cause. Simple fixes like a blown fuse or relay cost under $100, while replacing the AWD module can cost $500–$1,200 including labor.