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DTC codes / U02xx · Lost communication with a control module / U020D

U020DLost Communication With Wireless Accessory Charging Module B

U020D is a network communication code indicating that one or more control modules on the vehicle's Controller Area Network (CAN) bus have stopped receiving messages from the Wireless Accessory Charging Module B. The module itself may have lost power, ground, or CAN bus continuity, or its internal electronics may have failed, causing the rest of the network to flag it as missing.

SystemNetwork
Code typeGeneric (all makes)
SeverityLow
Fix difficultyIntermediate
AreaLost communication with a control module

Symptoms you may notice

  • Often no symptoms besides the warning light, because the wireless charging pad may still function or the vehicle may not display any message to the driver.
  • The wireless accessory charging pad stops charging or charges intermittently, especially when the phone is placed on the pad.
  • A message on the infotainment screen or driver information center stating that wireless charging is unavailable or that a system fault exists.
  • Other unrelated modules may log communication codes if the fault is a shared power or ground issue on the same circuit.
  • In some vehicles, the charging module may cause a parasitic draw that flattens the battery overnight if it fails to go to sleep.
  • The charging pad may become warm or hot to the touch even when no phone is present, indicating the module is powered but not communicating correctly.

Common causes, most likely first

  1. A blown fuse or poor connection in the power or ground circuit feeding the Wireless Accessory Charging Module B.
  2. Corroded, loose, or damaged connector pins at the charging module itself, often from spilled drinks or cabin humidity.
  3. A failed Wireless Accessory Charging Module B due to internal electronic failure, which is common on units exposed to heat and vibration.
  4. Open or shorted CAN bus wiring between the charging module and the network gateway or another module on the same bus segment.
  5. A low-voltage condition or weak battery that causes the charging module to drop offline intermittently, setting communication codes in multiple modules.
  6. A software or configuration mismatch in the charging module after a battery replacement or module replacement without proper initialization.
  7. Water intrusion into the charging module or its harness, particularly in vehicles with cupholders or storage trays near the pad.

How to diagnose and fix it

  1. Verify the battery state of charge and perform a voltage drop test on the charging module's power and ground circuits before condemning any part.
  2. Locate the Wireless Accessory Charging Module B, inspect its connector for corrosion, loose pins, or signs of liquid damage, and clean or repair as needed.
  3. Check the fuse that supplies the charging module and confirm that both key-on power and constant power are present at the module connector.
  4. Measure CAN bus resistance and voltage at the charging module connector to confirm the bus is intact and not shorted or open on that segment.
  5. If power, ground, and bus signals are good, substitute a known-good module or perform a module swap with a compatible unit to confirm the fault follows the module.
  6. After any repair, clear the code and perform a full network scan to confirm U020D does not return and that no other modules have related communication codes.
  7. If the module is replaced, follow the manufacturer's initialization or configuration procedure so the new module is recognized on the network.

What most technicians miss on U020D

  • A weak or failing battery is a frequent hidden cause of U020D because the charging module may be one of the first modules to drop offline when system voltage sags during cranking.
  • The code can set intermittently and never return after clearing if the root cause was a one-time low-voltage event, so a full drive cycle and network scan are needed before replacing parts.
  • Liquid damage from a spilled drink is a common but overlooked cause, and the module may look dry on the outside while corrosion is present inside the connector or on the circuit board.
  • U020D does not always mean the charging module is faulty; a poor ground shared with other cabin accessories can set this code while the module itself is healthy.
  • Some vehicles require the charging module to be configured or learned after replacement, and skipping that step will leave U020D stored even with a new module installed.

Can I keep driving with U020D?

The vehicle remains safe to drive because the wireless charging function is a convenience feature and does not affect steering, braking, or powertrain operation. Avoid relying on the charging pad until the fault is repaired, and address any battery or voltage issue promptly to prevent the code from affecting other modules.

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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