Code Definition

U0401 — Invalid Data Received From ECM/PCM

System: Network Communication  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About U0401

U0401 is a generic (obd-ii standard) network communication diagnostic trouble code. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

Scanning & clearing: Network (U) codes report communication faults between modules. When diagnosing U-codes, checking the vehicle's CAN bus integrity, supply/ground at each module, and reading all modules for related faults is usually the first step.

Because U0401 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

This DTC is set by a receiving module when it detects that the data received from the Engine Control Module (ECM) or Powertrain Control Module (PCM) over the CAN network is invalid, corrupt, or implausible. The fault typically triggers when the data fails range checks, is inconsistent with other sensor inputs, or doesn't match expected parameters based on operating conditions.

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