U011D

Universal

Lost Communication With All Wheel Drive Control Module

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle has detected that communication with the all-wheel-drive (AWD) control module is missing. That module helps coordinate AWD operation, and other vehicle systems may rely on its messages. AWD may be limited or unavailable, though the exact effect depends on the vehicle and the fault may be intermittent.

Report an error with this code

⚠️ Before You Begin (Safety First)

If an AWD warning appears or traction feels different, drive cautiously, especially on slippery or uneven roads. Stop in a safe place and seek assistance if the vehicle behaves unpredictably, loses drive, or displays other serious warnings.

Common Symptoms

  • An AWD or drivetrain warning may appear if the vehicle detects that the control module is not communicating.
  • AWD operation may be limited or unavailable, which can reduce traction in conditions where AWD would normally help.
  • Other systems that depend on AWD module messages may display warnings or store related communication codes.
  • There may be no noticeable symptoms if the communication loss is brief or intermittent.

Common Causes

  • A loose, damaged, or corroded connector or wire may interrupt communication with the AWD control module.
  • A power supply or ground problem, including a fuse or connection fault, may prevent the module from operating or communicating.
  • A fault in the vehicle communication network or another connected module may disrupt messages.
  • Low or unstable vehicle voltage may interfere with module communication.
  • An internal AWD control module fault is possible, but the code alone does not prove the module has failed.

Diagnostic Steps

  1. Note any AWD, drivetrain, or other warning messages and whether the problem is constant or intermittent; this helps describe the condition during diagnosis.
  2. With the vehicle safely parked, check the battery for obvious looseness or corrosion at accessible terminals. Do not disconnect the battery as a diagnostic shortcut, since that may erase useful information.
  3. If the owner's manual identifies an AWD-related fuse, check it only as directed by the manual. Replace a failed fuse only with the specified type and rating; if it fails again, stop and seek diagnosis.
  4. Visually inspect accessible AWD-module wiring and connectors for obvious damage, looseness, or moisture without forcing connectors apart or probing terminals.
  5. If the warning remains or returns, arrange a scan of all modules. A code reader that only accesses engine codes may not show the information needed to diagnose this communication fault.

When to Call a Professional

Have a technician scan all vehicle modules for related communication and voltage codes, then check whether the AWD module responds. They can inspect its power, ground, connectors, wiring, and the vehicle network using model-specific service information before deciding whether any component needs repair or replacement.

Compare component listings

Confirm diagnosis and vehicle fitment before buying. A listing does not prove that a part needs replacement. We may earn a commission from qualifying purchases.

Search Amazon Search eBay

Commonly Asked Questions

Does U011D prove that the AWD control module needs replacement?

No. It indicates lost communication with the module, which can result from power, ground, wiring, connector, network, voltage, or module problems. Diagnosis is needed to identify the cause.

Can I keep driving with this code?

The vehicle may remain drivable, but AWD assistance could be limited or unavailable. Drive cautiously and avoid conditions where reduced traction could create a hazard. Stop if the vehicle behaves unpredictably or loses drive.

Why might there be no symptoms?

A brief or intermittent communication interruption may set a code without an obvious change in driving. The fault can still recur, so note whether warnings return and have persistent codes diagnosed.

What testing helps distinguish a network fault from a module fault?

A technician can scan all modules, check communication status and related codes, and test the AWD module's power, ground, wiring, connectors, and network using vehicle-specific procedures.

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.