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DTC codes / U05xx · Network communication / U0545

U0545Invalid Data Received From Running Board Control Module A

U0545 is a communication fault indicating that a control module received invalid or corrupted data from the running board control module, which manages the deployable side steps on vehicles so equipped. The receiving module detected that the data frames from the running board module did not match the expected format or contained out-of-range values, so it flagged the signal as invalid rather than simply missing.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaNetwork communication

Symptoms you may notice

  • The running boards may fail to deploy or retract when a door opens or closes.
  • The running boards may move erratically, stop midway, or reverse direction unexpectedly.
  • A warning light or message may appear on the dashboard indicating a running board system fault.
  • The running board control module may be completely unresponsive to inputs.
  • Often no symptoms besides the warning light, with the running boards still operating normally.
  • Other modules on the same communication bus may log related communication codes.

Common causes, most likely first

  1. Corroded, loose, or damaged electrical connectors at the running board control module or its power and ground feeds.
  2. Chafed or broken wires in the harness running to the running board motors or sensors, often due to flexing or road debris.
  3. A failing running board control module that is sending corrupted data frames.
  4. Low battery voltage or poor charging system performance causing the module to reset or output invalid data.
  5. Water intrusion into the running board module or connector, leading to internal shorting or signal degradation.
  6. A software or calibration issue in the running board control module requiring a reflash or update.
  7. A fault in the communication network (CAN bus) wiring that corrupts data between modules.

How to diagnose and fix it

  1. Perform a full battery and charging system test to rule out low voltage as the root cause of invalid data.
  2. Inspect and clean all connectors at the running board control module, checking for corrosion, water intrusion, and tight fit.
  3. Visually inspect the wiring harness along the running board path for chafing, breaks, or loose grounds, and repair as needed.
  4. Use a scan tool to check for communication codes in other modules and to view live data from the running board module if available.
  5. Check for technical service bulletins (TSBs) or software updates for the running board control module and apply any applicable calibration.
  6. If wiring and power are confirmed good, substitute a known-good running board control module to see if the invalid data code clears.
  7. Clear codes and verify the repair by operating the running boards through several complete cycles and rechecking for the code.

When the running board module lies

  • A common misdiagnosis is to replace the running board control module immediately, but chafed wiring near the step motors often corrupts the data signal and mimics a module failure.
  • The code can set intermittently due to a weak battery or poor ground, so always load-test the battery and check ground connections before condemning any module.
  • Some vehicles require a relearn or calibration procedure after reconnecting the running board module, and skipping it can cause the code to reappear even with good hardware.
  • U0545 can be stored alongside U-codes for other modules if the communication bus itself is compromised, so a single-module fix may not resolve all codes.
  • The running board control module may still command the steps correctly while sending invalid status data, so the code does not always mean the steps are inoperative.

Can I keep driving with U0545?

You can generally continue driving if the running boards remain in a safe position, but avoid using them until diagnosed to prevent injury or damage from unexpected movement. If the steps are stuck in the deployed position, exercise caution when driving near curbs or obstacles.

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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