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DTC codes / U01xx · Lost communication with a control module / U015C

U015CLost Communication With Automated Driving System Control Module A

U015C is a generic network communication code indicating that one or more control modules have lost contact with the Automated Driving System Control Module A over the vehicle's Controller Area Network (CAN) bus. The computer detected that expected periodic messages from this module stopped arriving within a defined time window, which can disable advanced driver-assistance features.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaLost communication with a control module

Symptoms you may notice

  • Illumination of the malfunction indicator lamp (MIL) or a dedicated driver-assistance warning light
  • A message on the dash stating that automated driving features are unavailable or disabled
  • Adaptive cruise control, lane-keeping assist, or automated braking may stop functioning
  • Often no symptoms besides the warning light, with the vehicle driving normally
  • Intermittent operation of driver-assistance features that come and go with temperature or vibration
  • Other unrelated warning lights may appear if the module shares a bus segment with other systems

Common causes, most likely first

  1. Failed or intermittently failing Automated Driving System Control Module A
  2. Corroded, loose, or damaged electrical connector at the module
  3. Open or shorted CAN bus wiring between the module and the network
  4. Blown fuse or poor power/ground connection to the module
  5. Software corruption or failed module configuration after a battery replacement or update
  6. CAN bus network fault caused by another module dragging the bus down
  7. Water intrusion or physical damage to the module or its harness

How to diagnose and fix it

  1. Connect a scan tool and record all stored codes in every module, then clear codes and verify whether U015C returns immediately
  2. Check the fuse and relay supplying power to the Automated Driving System Control Module A, and inspect the ground connection
  3. Inspect the module connector for corrosion, pushed pins, or loose terminals, and perform a wiggle test while watching live data
  4. Measure CAN bus voltage and resistance at the module connector to confirm the bus is intact and not shorted
  5. If the module is unresponsive but power, ground, and bus are good, substitute a known-good module or perform a software reflash per manufacturer procedure
  6. Repair or replace damaged wiring or connectors, then clear codes and road-test to confirm communication is restored
  7. If the module itself has failed, replace and program it according to the manufacturer's service information

Before you replace the automated driving module

  • A weak or failing 12-volt battery can cause this code because modules drop offline during cranking, so load-test the battery before condemning any module.
  • The code often sets after a windshield replacement or body repair where the forward-facing camera or radar was disturbed, even though the module itself is fine.
  • U015C can be a secondary code caused by a different module shorting the CAN bus, so always check for other communication codes before replacing parts.
  • Some vehicles require a calibration drive after module replacement or battery disconnect, and skipping it leaves the code stored even with good hardware.
  • The Automated Driving System Control Module A may be integrated into another module on some platforms, so the repair might involve a combined unit rather than a stand-alone box.

Can I keep driving with U015C?

You can usually drive the vehicle, but do not rely on automated driving features such as adaptive cruise control or lane centering until the fault is repaired. If the warning light is accompanied by braking or steering warnings, have the vehicle inspected before continuing to drive.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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